Application of Load Carrying Sandwich Elements in Wind Turbine Blades

DEFF Research Database (Denmark)

Jensen, Jacob Fisker; Schultz, Jacob Pagh; Berggreen, Carl Christian

2005-01-01

The present work investigates the possibilities and drawbacks when applying sandwich as opposed to single skin composites in the flanges of the load carrying spar in a future 180 m wind turbine rotor. FEA is applied to investigate two basic designs with single skin and sandwich flanges respectively...

78 FR 53004 - Requested Administrative Waiver of the Coastwise Trade Laws: Vessel SECOND WIND; Invitation for...

Science.gov (United States)

2013-08-27

... Administrative Waiver of the Coastwise Trade Laws: Vessel SECOND WIND; Invitation for Public Comments AGENCY... SECOND WIND is: Intended Commercial Use of Vessel: ``Breakfast, lunch, and dinner cruises featuring... to the docket number of this notice and the vessel name in order for MARAD to properly consider the...

Mechanisms and Model Diversity of Trade-Wind Shallow Cumulus Cloud Feedbacks: A Review

Science.gov (United States)

Vial, Jessica; Bony, Sandrine; Stevens, Bjorn; Vogel, Raphaela

2017-11-01

Shallow cumulus clouds in the trade-wind regions are at the heart of the long standing uncertainty in climate sensitivity estimates. In current climate models, cloud feedbacks are strongly influenced by cloud-base cloud amount in the trades. Therefore, understanding the key factors controlling cloudiness near cloud-base in shallow convective regimes has emerged as an important topic of investigation. We review physical understanding of these key controlling factors and discuss the value of the different approaches that have been developed so far, based on global and high-resolution model experimentations and process-oriented analyses across a range of models and for observations. The trade-wind cloud feedbacks appear to depend on two important aspects: (1) how cloudiness near cloud-base is controlled by the local interplay between turbulent, convective and radiative processes; (2) how these processes interact with their surrounding environment and are influenced by mesoscale organization. Our synthesis of studies that have explored these aspects suggests that the large diversity of model responses is related to fundamental differences in how the processes controlling trade cumulus operate in models, notably, whether they are parameterized or resolved. In models with parameterized convection, cloudiness near cloud-base is very sensitive to the vigor of convective mixing in response to changes in environmental conditions. This is in contrast with results from high-resolution models, which suggest that cloudiness near cloud-base is nearly invariant with warming and independent of large-scale environmental changes. Uncertainties are difficult to narrow using current observations, as the trade cumulus variability and its relation to large-scale environmental factors strongly depend on the time and/or spatial scales at which the mechanisms are evaluated. New opportunities for testing physical understanding of the factors controlling shallow cumulus cloud responses using

Mechanisms and Model Diversity of Trade-Wind Shallow Cumulus Cloud Feedbacks: A Review

Science.gov (United States)

Vial, Jessica; Bony, Sandrine; Stevens, Bjorn; Vogel, Raphaela

Shallow cumulus clouds in the trade-wind regions are at the heart of the long standing uncertainty in climate sensitivity estimates. In current climate models, cloud feedbacks are strongly influenced by cloud-base cloud amount in the trades. Therefore, understanding the key factors controlling cloudiness near cloud-base in shallow convective regimes has emerged as an important topic of investigation. We review physical understanding of these key controlling factors and discuss the value of the different approaches that have been developed so far, based on global and high-resolution model experimentations and process-oriented analyses across a range of models and for observations. The trade-wind cloud feedbacks appear to depend on two important aspects: (1) how cloudiness near cloud-base is controlled by the local interplay between turbulent, convective and radiative processes; (2) how these processes interact with their surrounding environment and are influenced by mesoscale organization. Our synthesis of studies that have explored these aspects suggests that the large diversity of model responses is related to fundamental differences in how the processes controlling trade cumulus operate in models, notably, whether they are parameterized or resolved. In models with parameterized convection, cloudiness near cloud-base is very sensitive to the vigor of convective mixing in response to changes in environmental conditions. This is in contrast with results from high-resolution models, which suggest that cloudiness near cloud-base is nearly invariant with warming and independent of large-scale environmental changes. Uncertainties are difficult to narrow using current observations, as the trade cumulus variability and its relation to large-scale environmental factors strongly depend on the time and/or spatial scales at which the mechanisms are evaluated. New opportunities for testing physical understanding of the factors controlling shallow cumulus cloud responses using

Monsoon wind and maritime trade: A case study of historical evidence from Orissa, India

Digital Repository Service at National Institute of Oceanography (India)

Tripati, S.; Raut, L.N.

Monsoon plays a predominant role in the daily life of the people of South Asia. The use of monsoon wind in the Indian Ocean for maritime trade was a boon to the sailing ships to reach overseas countries. It is believed that Hippalus discovered...

Operation of Power Grids with High Penetration of Wind Power

Science.gov (United States)

Al-Awami, Ali Taleb

The integration of wind power into the power grid poses many challenges due to its highly uncertain nature. This dissertation involves two main components related to the operation of power grids with high penetration of wind energy: wind-thermal stochastic dispatch and wind-thermal coordinated bidding in short-term electricity markets. In the first part, a stochastic dispatch (SD) algorithm is proposed that takes into account the stochastic nature of the wind power output. The uncertainty associated with wind power output given the forecast is characterized using conditional probability density functions (CPDF). Several functions are examined to characterize wind uncertainty including Beta, Weibull, Extreme Value, Generalized Extreme Value, and Mixed Gaussian distributions. The unique characteristics of the Mixed Gaussian distribution are then utilized to facilitate the speed of convergence of the SD algorithm. A case study is carried out to evaluate the effectiveness of the proposed algorithm. Then, the SD algorithm is extended to simultaneously optimize the system operating costs and emissions. A modified multi-objective particle swarm optimization algorithm is suggested to identify the Pareto-optimal solutions defined by the two conflicting objectives. A sensitivity analysis is carried out to study the effect of changing load level and imbalance cost factors on the Pareto front. In the second part of this dissertation, coordinated trading of wind and thermal energy is proposed to mitigate risks due to those uncertainties. The problem of wind-thermal coordinated trading is formulated as a mixed-integer stochastic linear program. The objective is to obtain the optimal tradeoff bidding strategy that maximizes the total expected profits while controlling trading risks. For risk control, a weighted term of the conditional value at risk (CVaR) is included in the objective function. The CVaR aims to maximize the expected profits of the least profitable scenarios, thus

Large-scale wind power integration and wholesale electricity trading benefits: Estimation via an ex post approach

International Nuclear Information System (INIS)

Gil, Hugo A.; Gomez-Quiles, Catalina; Riquelme, Jesus

2012-01-01

The integration of large-scale wind power has brought about a series of challenges to the power industry, but at the same time a number of benefits are being realized. Among those, the ability of wind power to cause a decline in the electricity market prices has been recognized. In quantifying this effect, some models used in recent years are based on simulations of the market supply-side and the price clearing process. The accuracy of the estimates depend on the quality of the input data, the veracity of the adopted scenarios and the rigorousness of the solution technique. In this work, a series of econometric techniques based on actual ex post wind power and electricity price data are implemented for the estimation of the impact of region-wide wind power integration on the local electricity market clearing prices and the trading savings that stem from this effect. The model is applied to the case of Spain, where the estimated savings are compared against actual credit and bonus expenses to ratepayers. The implications and extent of these results for current and future renewable energy policy-making are discussed. - Highlights: ► Wholesale electricity market trading benefits by wind power are quantified. ► Actual wind power forecast-based bids and electricity price data from Spain are used. ► Different econometric tools are used and compared for improved estimation accuracy. ► Estimated benefits outweigh current credit overhead paid to wind farms in Spain. ► An economically efficient benefit surplus allocation framework is proposed.

Strategic wind power trading considering rival wind power production

DEFF Research Database (Denmark)

Exizidis, Lazaros; Kazempour, Jalal; Pinson, Pierre

2016-01-01

In an electricity market with high share of wind power, it is expected that wind power producers may exercise market power. However, wind producers have to cope with wind’s uncertain nature in order to optimally offer their generation, whereas in a market with more than one wind producers, uncert...... depending on the rival’s wind generation, given that its own expected generation is not high. Finally, as anticipated, expected system cost is higher when both wind power producers are expected to have low wind power generation......In an electricity market with high share of wind power, it is expected that wind power producers may exercise market power. However, wind producers have to cope with wind’s uncertain nature in order to optimally offer their generation, whereas in a market with more than one wind producers......, uncertainty of rival wind power generation should also be considered. Under this context, this paper addresses the impact of rival wind producers on the offering strategy and profits of a pricemaker wind producer. A stochastic day-ahead market setup is considered, which optimizes the day-ahead schedules...

Climate Prediction Center (CPC)Area-averaged 850-hPa Western Pacific Trade Wind Anomalies

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This is one of the CPC?s Monthly Atmospheric and SST Indices. It is the 850-hPa trade wind anomalies averaged over the area 5oN ? 5oS, 135oE-180o (western equatorial...

Climate Prediction Center (CPC)Area-averaged 850-hPa Eastern Pacific Trade Wind Anomalies

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This is one of the CPC?s Monthly Atmospheric and SST Indices. It is the 850-hPa trade wind anomalies averaged over the area 5oN ? 5oS, 135oW-120oW (eastern...

Climate Prediction Center (CPC)Area-averaged 850-hPa Central Pacific Trade Wind Anomalies

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This is one of the CPC?s Monthly Atmospheric and SST Indices. It is the 850-hPa trade wind anomalies averaged over the area 5oN ? 5oS, 175oW-140oW (central...

Carry

DEFF Research Database (Denmark)

Koijen, Ralph S.J.; Moskowitz, Tobias J.; Heje Pedersen, Lasse

that include global equities, global bonds, currencies, commodities, US Treasuries, credit, and equity index options. This predictability underlies the strong returns to "carry trades" that go long high-carry and short low-carry securities, applied almost exclusively to currencies, but shown here...

A study of rotor and platform design trade-offs for large-scale floating vertical axis wind turbines

Science.gov (United States)

Griffith, D. Todd; Paquette, Joshua; Barone, Matthew; Goupee, Andrew J.; Fowler, Matthew J.; Bull, Diana; Owens, Brian

2016-09-01

Vertical axis wind turbines are receiving significant attention for offshore siting. In general, offshore wind offers proximity to large populations centers, a vast & more consistent wind resource, and a scale-up opportunity, to name a few beneficial characteristics. On the other hand, offshore wind suffers from high levelized cost of energy (LCOE) and in particular high balance of system (BoS) costs owing to accessibility challenges and limited project experience. To address these challenges associated with offshore wind, Sandia National Laboratories is researching large-scale (MW class) offshore floating vertical axis wind turbines (VAWTs). The motivation for this work is that floating VAWTs are a potential transformative technology solution to reduce offshore wind LCOE in deep-water locations. This paper explores performance and cost trade-offs within the design space for floating VAWTs between the configurations for the rotor and platform.

Proceedings of CanWEA's 24. annual conference and trade show : fast forward to wind

International Nuclear Information System (INIS)

2008-01-01

The Canadian Wind Energy Association's conference and trade show provides an annual forum for wind developers, wind turbine manufacturers, component suppliers and electric utility operators to discuss issues currently facing the wind industry and measures that must be taken to ensure its future growth in Canada. As part of a range of renewable energy initiatives designed to help Canada reach its target commitments for the Kyoto Protocol, the expansion of the wind industry is expected to reduce the country's greenhouse gas (GHG) emissions and provide significant economic benefits to local communities. However, the wind industry is facing a number of challenges and constraints due to a lack of clear policies from provincial and federal governments. Significant infrastructure investments and financial incentives will need to be put in place in order to provide a secure foundation for future growth. The conference was divided into 3 tracks: (1) wind energy enhancement in Canada; (2) trends in wind research and development; and (3) the business of wind. Presentations examined solutions related to wind energy integration with electricity grids and discussed methods of building social acceptance of wind projects in communities. Advances in forecasting and computerized simulations were presented, and methods of negotiating environmental assessments and planning permit requirements were discussed. The conference also included a small wind pre-conference that addressed issues related to the growth and manufacturing of small wind turbines in Canada. The conference featured 88 presentations, of which 69 have been catalogued separately for inclusion in this database. tabs., figs

A risk-averse optimization model for trading wind energy in a market environment under uncertainty

International Nuclear Information System (INIS)

Pousinho, H.M.I.; Mendes, V.M.F.; Catalao, J.P.S.

2011-01-01

In this paper, a stochastic programming approach is proposed for trading wind energy in a market environment under uncertainty. Uncertainty in the energy market prices is the main cause of high volatility of profits achieved by power producers. The volatile and intermittent nature of wind energy represents another source of uncertainty. Hence, each uncertain parameter is modeled by scenarios, where each scenario represents a plausible realization of the uncertain parameters with an associated occurrence probability. Also, an appropriate risk measurement is considered. The proposed approach is applied on a realistic case study, based on a wind farm in Portugal. Finally, conclusions are duly drawn. -- Highlights: → We model uncertainties on energy market prices and wind power production. → A hybrid intelligent approach generates price-wind power scenarios. → Risk aversion is also incorporated in the proposed stochastic programming approach. → A realistic case study, based on a wind farm in Portugal, is provided. → Our approach allows selecting the best solution according to the desired risk exposure level.

Effects of trade-wind strength and direction on the leeside circulations and rainfall of the island of Hawaii

Science.gov (United States)

Yang Yang; Yi-Leng Chen; Francis M. Fujioka

2009-01-01

The leeside circulations and weather of the island of Hawaii were studied from the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) land surface model simulations for eight strong (∼7.9 m s−1) and eight weak (∼5.2 m s−1) trade-wind days and for five days with southeasterly trades (∼7.1 m s

Analysis of the wind rose at Itaorna, Brazil

International Nuclear Information System (INIS)

Nicolli, D.

1982-05-01

The Angra-I nuclear power plant is located on the southeastern coast of Brazil, in a bowl-shaped area with hills on three sides and a bay on the fourth side. To the north the surrounding hills rise to more than 600 meters, in the other directions they are lower. At the botton of this area a meteorological mast 50 meters high was installed. Hourly measurements of temperature differences between two levels, as well as wind speed and direction at 50m height were carried out. The wind speed and direction are analysed. The daily air flow at the site shows two distinct characteristics: one nocturnal flow from NE due to the combined effects of the trade and the katabatic winds and a diurnal flow from SW-W generated by the sea breezes. Throughout the year this 'normal' condition is disturbed by low pressure systems that move over the region. For about 10% of the time these weather systems account for the disturbed flow regime in which the winds change direction in a counterclockwise sense. During the day the sea breezes are suppressed by the backing of the winds as well as the trade and katabatic winds during the night. (Author) [pt

Pool Strategy of a Price-Maker Wind Power Producer

DEFF Research Database (Denmark)

Zugno, Marco; Morales González, Juan Miguel; Pinson, Pierre

2013-01-01

We consider the problem of a wind power producer trading energy in short-term electricity markets. The producer is a price-taker in the day-ahead market, but a price-maker in the balancing market, and aims at optimizing its expected revenues from these market floors. The problem is formulated...... or median forecast of wind power distribution. Finally, sensitivity analyses are carried out to assess the impact on the offering strategy of the producer's penetration in the market, of the correlation between wind power production and residual system deviation, and of the shape of the forecast...

A Unified Trading Model Based on Robust Optimization for Day-Ahead and Real-Time Markets with Wind Power Integration

Directory of Open Access Journals (Sweden)

Yuewen Jiang

2017-04-01

Full Text Available In a conventional electricity market, trading is conducted based on power forecasts in the day-ahead market, while the power imbalance is regulated in the real-time market, which is a separate trading scheme. With large-scale wind power connected into the power grid, power forecast errors increase in the day-ahead market which lowers the economic efficiency of the separate trading scheme. This paper proposes a robust unified trading model that includes the forecasts of real-time prices and imbalance power into the day-ahead trading scheme. The model is developed based on robust optimization in view of the undefined probability distribution of clearing prices of the real-time market. For the model to be used efficiently, an improved quantum-behaved particle swarm algorithm (IQPSO is presented in the paper based on an in-depth analysis of the limitations of the static character of quantum-behaved particle swarm algorithm (QPSO. Finally, the impacts of associated parameters on the separate trading and unified trading model are analyzed to verify the superiority of the proposed model and algorithm.

Trading wind generation from short-term probabilistic forecasts of wind power

DEFF Research Database (Denmark)

Pinson, Pierre; Chevallier, Christophe; Kariniotakis, Georges

2007-01-01

Due to the fluctuating nature of the wind resource, a wind power producer participating in a liberalized electricity market is subject to penalties related to regulation costs. Accurate forecasts of wind generation are therefore paramount for reducing such penalties and thus maximizing revenue......, as well as on modeling of the sensitivity a wind power producer may have to regulation costs. The benefits resulting from the application of these strategies are clearly demonstrated on the test case of the participation of a multi-MW wind farm in the Dutch electricity market over a year....... participation. Such strategies permit to further increase revenues and thus enhance competitiveness of wind generation compared to other forms of dispatchable generation. This paper formulates a general methodology for deriving optimal bidding strategies based on probabilistic forecasts of wind generation...

A Unified Trading Model Based on Robust Optimization for Day-Ahead and Real-Time Markets with Wind Power Integration

DEFF Research Database (Denmark)

Jiang, Yuewen; Chen, Meisen; You, Shi

2017-01-01

In a conventional electricity market, trading is conducted based on power forecasts in the day-ahead market, while the power imbalance is regulated in the real-time market, which is a separate trading scheme. With large-scale wind power connected into the power grid, power forecast errors increase...... in the day-ahead market which lowers the economic efficiency of the separate trading scheme. This paper proposes a robust unified trading model that includes the forecasts of real-time prices and imbalance power into the day-ahead trading scheme. The model is developed based on robust optimization in view...... of the undefined probability distribution of clearing prices of the real-time market. For the model to be used efficiently, an improved quantum-behaved particle swarm algorithm (IQPSO) is presented in the paper based on an in-depth analysis of the limitations of the static character of quantum-behaved particle...

Numerical simulations of island-scale airflow over Maui and the Maui vortex under summer trade wind conditions

Science.gov (United States)

DaNa L. Carlis; Yi-Leng Chen; Vernon R. Morris

2010-01-01

The fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) coupled with the Noah land surface model (LSM) is employed to simulate island-scale airflow and circulations over Maui County, Hawaii, under summer trade wind conditions, during July–August 2005. The model forecasts are validated by surface observations with good agreement.

Comparative assessment of hydrogen storage and international electricity trade for a Danish energy system with wind power and hydrogen/fuel cell technologies. Final project report

Energy Technology Data Exchange (ETDEWEB)

Soerensen, Bent (Roskilde University, Energy, Environment and Climate Group, Dept. of Environmental, Social and Spatial Change (ENSPAC) (DK)); Meibom, P.; Nielsen, Lars Henrik; Karlsson, K. (Technical Univ. of Denmark, Risoe National Laboratory for Sustainable Energy, Systems Analysis Dept., Roskilde (DK)); Hauge Pedersen, A. (DONG Energy, Copenhagen (DK)); Lindboe, H.H.; Bregnebaek, L. (ea Energy Analysis, Copenhagen (DK))

2008-02-15

This report is the final outcome of a project carried out under the Danish Energy Agency's Energy Research Programme. The aims of the project can be summarized as follows: 1) Simulation of an energy system with a large share of wind power and possibly hydrogen, including economic optimization through trade at the Nordic power pool (exchange market) and/or use of hydrogen storage. The time horizon is 50 years. 2) Formulating new scenarios for situations with and without development of viable fuel cell technologies. 3) Updating software to solve the abovementioned problems. The project has identified a range of scenarios for all parts of the energy system, including most visions of possible future developments. (BA)

The significance of interconnector counter-trading in a security constrained electricity market

International Nuclear Information System (INIS)

Higgins, P.; Li, K.; Devlin, J.; Foley, A.M.

2015-01-01

Throughout the European Union there is an increasing amount of wind generation being dispatched-down due to the binding of power system operating constraints from high levels of wind generation. This paper examines the impact a system non-synchronous penetration limit has on the dispatch-down of wind and quantifies the significance of interconnector counter-trading to the priority dispatching of wind power. A fully coupled economic dispatch and security constrained unit commitment model of the Single Electricity Market of the Republic of Ireland and Northern Ireland and the British Electricity Trading and Transmission Arrangement was used in this study. The key finding was interconnector counter-trading reduces the impact the system non-synchronous penetration limit has on the dispatch-down of wind. The capability to counter-trade on the interconnectors and an increase in system non-synchronous penetration limit from 50% to 55% reduces the dispatch-down of wind by 311 GW h and decreases total electricity payments to the consumer by €1.72/MW h. In terms of the European Union electricity market integration, the results show the importance of developing individual electricity markets that allow system operators to counter-trade on interconnectors to ensure the priority dispatch of the increasing levels of wind generation. - Highlights: • Interconnector counter-trading reduces the system marginal price in the SEM. • Dispatch-down of wind power is reduced due to interconnector counter-trading. • A 5% increase in the SNSP limit can reduce wind power dispatched-down by 50%. • An increase in the SNSP limit and installed wind capacity reduces the SMP.

Impact of Flexibility Options on Grid Economic Carrying Capacity of Solar and Wind: Three Case Studies

Energy Technology Data Exchange (ETDEWEB)

Denholm, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Novacheck, Joshua [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jorgenson, Jennie [National Renewable Energy Lab. (NREL), Golden, CO (United States); O' Connell, Matthew [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-12-01

In this study, we attempt to quantify the benefits of various options of grid flexibility by measuring their impact on two measures: economic carrying capacity and system costs. Flexibility can increase economic carrying capacity and reduce overall system costs. In some cases, options that provide a limited increase in economic carrying capacity can provide significant operational savings, thus demonstrating the need to evaluate flexibility options using multiple metrics. The value of flexibility options varies regionally due to different generation mixes and types of renewables. The more rapid decline in PV value compared to wind makes PV more dependent on adding flexibility options, including transmission and energy storage.

Spatial Trade-Offs between Wind Power Production and Bird Collision Avoidance in Agricultural Landscapes

Directory of Open Access Journals (Sweden)

Marcus Eichhorn

2010-06-01

Full Text Available The expansion of renewable energy production is seen as an appropriate way to mitigate climate change. Renewable energies are not free of negative external effects on humans and the natural environment. We analyzed the conflict between wind power production and bird protection through the example of one of the most sensitive species, the red kite (Milvus milvus in West Saxony, Germany. We investigated a large number of potential land use scenarios, defined by whether or not each potential site contained a wind turbine (WT. Based on meteorological and ornithological data, we evaluated the land use scenarios for their annual energy supply and impact on the red kite. We identified the efficient land use scenarios that maximized energy supply for a given ecological impact. Within the scope of our analysis, the current allocation of WTs in the study region was considered inefficient. The set of efficient scenarios allowed us to draw conclusions on the trade-offs involved. We developed an indicator that measures the severity of the conflict between wind power production and bird protection. Increasing the minimum distance of WTs to settlements beyond the legal requirements in order to minimize the impact on humans further intensifies the conflict. Our results can support planning authorities in their development of long-term regional plans by identifying areas that are most suitable for wind power production from an integrated point of view.

Wind power bidding in electricity markets with high wind penetration

International Nuclear Information System (INIS)

Vilim, Michael; Botterud, Audun

2014-01-01

Highlights: • We analyze the pricing systems and wind power trading in electricity markets. • We propose a model that captures the relation between market prices and wind power. • A probabilistic bidding model can increase profits for wind power producers. • Profit maximizing bidding strategies carry risks for power system operators. • We conclude that modifications of current market designs may be needed. - Abstract: Objective: The optimal day-ahead bidding strategy is studied for a wind power producer operating in an electricity market with high wind penetration. Methods: A generalized electricity market is studied with minimal assumptions about the structure of the production, bidding, or consumption of electricity. Two electricity imbalance pricing schemes are investigated, the one price and the two price scheme. A stochastic market model is created to capture the price effects of wind power production and consumption. A bidding algorithm called SCOPES (Supply Curve One Price Estimation Strategy) is developed for the one price system. A bidding algorithm called MIMICS (Multivariate Interdependence Minimizing Imbalance Cost Strategy) is developed for the two price system. Results: Both bidding strategies are shown to have advantages over the assumed “default” bidding strategy, the point forecast. Conclusion: The success of these strategies even in the case of high deviation penalties in a one price system and the implicit deviation penalties of the two price system has substantial implications for power producers and system operators in electricity markets with a high level of wind penetration. Practice implications: From an electricity market design perspective, the results indicate that further penalties or regulations may be needed to reduce system imbalance

Optimizing the number and locations of turbines in a wind farm addressing energy-noise trade-off: A hybrid approach

International Nuclear Information System (INIS)

Mittal, Prateek; Mitra, Kishalay; Kulkarni, Kedar

2017-01-01

Highlights: • Concurrent resolution of turbine number and locations during micro-siting. • Effect of noise on energy-noise multi-objective optimization is demonstrated. • A hybrid algorithm is proposed utilizing probabilistic and deterministic methods. • ∼24% improved performance is achieved over the benchmark case study. • ∼29% enhanced efficiency over real-binary genetic algorithm alone can be observed. - Abstract: Micro-siting is an optimal way of placing turbines inside a wind farm while considering various design objectives and constraints. Using a well-established Jensen wake model and ISO-9613-2 noise calculation, this study performs a wind farm layout optimization based on a multi-objective trade-off between minimization of the noise propagation and maximization of the energy generation. A novel hybrid methodology is developed which is a combination of probabilistic real-binary coded multi-objective evolutionary algorithm and a newly proposed deterministic gradient based non-dominated normalized normal constraint method. Based on the Inverted Generational Distance metric, the performance of the proposed method is found to be better than the conventional normalized normal constraint method or the concerned evolutionary method alone. Moreover, in contrast to the previous studies, the generated non-dominated front is capable of providing a trade-off between various alternative energy-noise solutions, along with an additional information about the corresponding turbine numbers and their optimal location coordinates. As a result, the decision maker can choose from different competing wind turbine layouts based on existing noise and other standard regulations.

TradeWind Deliverable 2.2: Forecast error of aggregated wind power

DEFF Research Database (Denmark)

Giebel, Gregor; Sørensen, Poul Ejnar; Holttinen, Hannele

2007-01-01

Estimates of forecast error of aggregated production for time horizons of intraday and dayahead markets in future will be produced. This will be done by reference to published studies of forecasting for wind generation, and from internal knowledge of WP2 participants. Modelling of wind power fluctuations...

Integrating drivers influencing the detection of plant pests carried in the international cut flower trade.

Science.gov (United States)

Areal, F J; Touza, J; MacLeod, A; Dehnen-Schmutz, K; Perrings, C; Palmieri, M G; Spence, N J

2008-12-01

This paper analyses the cut flower market as an example of an invasion pathway along which species of non-indigenous plant pests can travel to reach new areas. The paper examines the probability of pest detection by assessing information on pest detection and detection effort associated with the import of cut flowers. We test the link between the probability of plant pest arrivals, as a precursor to potential invasion, and volume of traded flowers using count data regression models. The analysis is applied to the UK import of specific genera of cut flowers from Kenya between 1996 and 2004. There is a link between pest detection and the Genus of cut flower imported. Hence, pest detection efforts should focus on identifying and targeting those imported plants with a high risk of carrying pest species. For most of the plants studied, efforts allocated to inspection have a significant influence on the probability of pest detection. However, by better targeting inspection efforts, it is shown that plant inspection effort could be reduced without increasing the risk of pest entry. Similarly, for most of the plants analysed, an increase in volume traded will not necessarily lead to an increase in the number of pests entering the UK. For some species, such as Carthamus and Veronica, the volume of flowers traded has a significant and positive impact on the likelihood of pest detection. We conclude that analysis at the rank of plant Genus is important both to understand the effectiveness of plant pest detection efforts and consequently to manage the risk of introduction of non-indigenous species.

Wind energy

International Nuclear Information System (INIS)

Portilla S, L.A.

1995-01-01

The wind energy or eolic energy is a consequence of solar energy, the one which is absorbed by the atmosphere and is transformed into energy of movement of large bulks of air. In this process the atmosphere acts as the filter to the solar radiation and demotes the ultraviolet beams that result fatal to life in the Earth. The ionosphere is the most external cap and this is ionized by means of absorption process of ultraviolet radiation arising to the Sun. The atmosphere also acts as a trap to the infrared radiation, it that results from the continual process of energetic degradation. In this way, the interaction between Earth - Atmospheres, is behaved as a great greenhouse, maintaining the constant temperatures, including in the dark nights. Processes as the natural convection (that occur by the thermodynamic phenomenon), equatorial calmness, trade winds and against trade winds and global distribution of the air currents are described. The other hand, techniques as the transformation of the wind into energy and its parameters also are shown

A Wind Forecasting System for Energy Application

Science.gov (United States)

Courtney, Jennifer; Lynch, Peter; Sweeney, Conor

2010-05-01

probabilistic wind forecasts which will be invaluable in wind energy management. In brief, this method turns the ensemble forecasts into a calibrated predictive probability distribution. Each ensemble member is provided with a 'weight' determined by its relative predictive skill over a training period of around 30 days. Verification of data is carried out using observed wind data from operational wind farms. These are then compared to existing forecasts produced by ECMWF and Met Eireann in relation to skill scores. We are developing decision-making models to show the benefits achieved using the data produced by our wind energy forecasting system. An energy trading model will be developed, based on the rules currently used by the Single Electricity Market Operator for energy trading in Ireland. This trading model will illustrate the potential for financial savings by using the forecast data generated by this research.

QuikSCAT and SSM/I ocean surface winds for wind energy

DEFF Research Database (Denmark)

Hasager, Charlotte Bay; Astrup, Poul; Nielsen, Per

2007-01-01

-European mid-latitudes and in the Atlantic trade belt zone are compared. Distinct differences are identified and these agree well with independent data from meteorological masts in the two regions. Seven years of twice daily observations from QuikSCAT are used for the offshore wind resource assessment. Wind...

Stochastic Optimal Wind Power Bidding Strategy in Short-Term Electricity Market

DEFF Research Database (Denmark)

Hu, Weihao; Chen, Zhe; Bak-Jensen, Birgitte

2012-01-01

Due to the fluctuating nature and non-perfect forecast of the wind power, the wind power owners are penalized for the imbalance costs of the regulation, when they trade wind power in the short-term liberalized electricity market. Therefore, in this paper a formulation of an imbalance cost...... minimization problem for trading wind power in the short-term electricity market is described, to help the wind power owners optimize their bidding strategy. Stochastic optimization and a Monte Carlo method are adopted to find the optimal bidding strategy for trading wind power in the short-term electricity...... market in order to deal with the uncertainty of the regulation price, the activated regulation of the power system and the forecasted wind power generation. The Danish short-term electricity market and a wind farm in western Denmark are chosen as study cases due to the high wind power penetration here...

76 FR 58774 - Trade Mission to Southeast Asia in Conjunction With Trade Winds-Asia

Science.gov (United States)

2011-09-22

... trade mission stop in either: Malaysia (Kuala Lumpur) or Indonesia (Jakarta). Each trade mission stop... cross section of industries with growth potential in Singapore, Vietnam, Thailand, Malaysia and... equipment, safety and security equipment, automotive parts and service equipment, and logistics and...

Developments on the wind energy scene

International Nuclear Information System (INIS)

Anon.

1996-01-01

The recently published report of the British Wind Energy Association (BWEA), entitled ''Power for a Sustainable Future'', is summarised. It calls on the government to: set a target of 10% of United Kingdom electricity from wind by 2025; encourage green energy trading by not charging value added tax on electricity from renewable sources; establish a fair market price for wind power; adopt a new development policy for renewable energies based on a rolling programme of equitable fixed contracts to encourage long-term investment; broaden the basis of the final Non Fossil Fuel Option, introducing new development bands and increasing the number of projects in Scotland which has half of Britain's wind resource; continue support for research and development into wind energy technologies and manufacturing methods; implement foreign aid programmes to benefit the British wind industry as well as aid recipients; continue to develop international standards for turbine design and construction to facilitate trade for manufacturers throughout the European Union. (UK)

Wind power - energy from air

International Nuclear Information System (INIS)

Alakangas, E.

1998-01-01

The wind conditions for wind power generation are favourable on the coast, in the archipelagos and in the fell areas of Finland. About 7 MW of wind power has been constructed in Finland, with the investment support of the Ministry of Trade and Industry. In 1995 about 11 GWh were produced by wind energy. A number of wind power plants are under design on the coasts of the Gulf of Finland and the Gulf of Bothnia as well as on the Aaland Islands. The first arctic wind park was constructed in Lapland in September 1996

Agricultural Trade Barriers 10 years later Uruguay Round Trade Agreement Signature

OpenAIRE

Mahia, R.; Arce, Rafael de; Escribano, Gonzalo

2005-01-01

In this paper, an analysis of current state of agricultural trade barriers is carried out alter ten years of Uruguay Round Agricultural Trade Agreement Signature The descriptive analysis showed that small advances in trade barriers removing have been taken out. About the heterogeneity in tariff applications, tariff progresivity and peak tariffs, the same situation is pointed out.

Maximising the commercial value of wind energy through forecasting

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-01

The aim of this project, initiated by the DTI, was to advise the electricity industry on the possibility of using weather forecasting to improve the commercial position of both inland and off-shore wind farms under the New Electricity Trading Arrangements (NETA) and to develop appropriate strategies for the use of forecasting. The work has clearly shown that, by using forecasting, wind generators can make money on the Short-Term Power Exchange, increasing their revenue over and above that achieved in the cash-out market. For inland sites, the average annual increased earnings are estimated around 5.8%, rising to 7.5% off-shore. The forecast value methodology developed by the Meteorological Office during the project has proven to be a valuable tool for analysing wind farm trading under NETA. The methodology has the potential to be used by wind farm operators and suppliers wishing to actively trade wind on the Short-Term Power Exchange. It is recommended that further verification of the methodology and development for active use is required. Specifically, a lack of 'true' off-shore wind data has been identified. It appears that off-shore wind farms stand to gain most from forecasting and the report calls for off-shore wind observation data to be made available to allow better verification of the off-shore forecasting models to be undertaken. (author)

Past, Present and Future: GATT, Free Trade Areas and... the World Trade Organization?

Directory of Open Access Journals (Sweden)

Gonzalo Bernardos

1995-07-01

Full Text Available The aims of this article are, on the one hand, to carry out a reconsideration of the workings of the commercial system since the Bretton Woods agreements and, on the other hand, to make some reflections regarding the function that the World Trade Organizationmust carry out in the future in a world divided, probably just like now, in regional areas of free trade. In order to achieve these aims the following are specified: the bases on which the liberalization of trade has been founded after the Second World War, the causes whichprovoked the wave of protectionism in the Eighties, the reasons which have brought about the division of the world into trading blocks as well as the need for an organization which encourages inter-regional trade and reduces the commercial wars between these blocks.

ewec 2007 - Europe's premier wind energy event

International Nuclear Information System (INIS)

Chaviaropoulos, T.

2007-01-01

This online collection of papers - the ewec 2007 proceedings - reflects the various sessions and lectures presented at the ewec wind-energy convention held in Milan in 2007. The first day's sessions looked at the following topics: Renewable Energy Roadmap, the changing structure of the wind industry, politics and programmes, aerodynamics and innovation in turbine design, wind resources and site characterisation (2 sessions), energy scenarios, harmonisation of incentive schemes, structural design and materials, forecasting, integration studies, integrating wind into electricity markets, wind-turbine electrical systems and components, as well as loads, noise and wakes. The second day included sessions on offshore: developments and prospects, extreme wind conditions and forecasting techniques, small wind turbines, distributed generation and autonomous systems cost effectiveness, cost effectiveness of wind energy, financing wind energy concepts, wind and turbulence, wind power plants and grid integration, offshore technology, global challenges and opportunities, aero-elasticity, loads and control, operations and maintenance, carbon trading and the emission trading schemes, investment strategies of power producers, wind power plants and grid integration, wind turbine electrical systems and components, and wakes. The third day offered sessions on environmental issues, condition monitoring, operation and maintenance, structural design and materials, the Up-Wind workshop, winning hearts and minds, offshore technology, advances in measuring methods and advancing drive-train reliability. In a closing session the conference was summarised, awards for poster contributions were made and the Poul la Cour Prize was presented

Impact of Flexibility Options on Grid Economic Carrying Capacity of Solar and Wind: Three Case Studies

Energy Technology Data Exchange (ETDEWEB)

Denholm, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Novacheck, Joshua [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jorgenson, Jennie [National Renewable Energy Lab. (NREL), Golden, CO (United States); O' Connell, Matthew [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-12-01

In this study, we attempt to quantify the benefits of various options of grid flexibility by measuring their impact on two measures: economic carrying capacity and system costs. Flexibility can increase ECC and reduce overall system costs. In some cases, options that provide a limited increase in ECC can provide significant operational savings, thus demonstrating the need to evaluate flexibility options using multiple metrics. The value of flexibility options varies regionally due to different generation mixes and types of renewables. The more rapid decline in PV value compared to wind makes PV more dependent on adding flexibility options, including transmission and energy storage.

On the spatial hedging effectiveness of German wind power futures for wind power generators

DEFF Research Database (Denmark)

Christensen, Troels Sønderby; Pircalabu, Anca

2018-01-01

The wind power futures recently introduced on the German market fill the gap of a standardized product that addresses directly the volume risk in wind power trading. While the German wind power futures entail risk-reducing benefits for wind power generators generally speaking, it remains unclear...... the extent of these benefits across wind farms with different geographical locations. In this paper, we consider the wind utilization at 31 different locations in Germany, and for each site, we propose a copula model for the joint behavior of the site-specific wind index and the overall German wind index....... Our results indicate that static mixture copulas are preferred to the stand-alone copula models usually employed in the economic literature. Further, we find evidence of asymmetric dependence and upper tail dependence. To quantify the benefits of wind power futures at each wind site, we perform...

Forecasting wind power production from a wind farm using the RAMS model

DEFF Research Database (Denmark)

Tiriolo, L.; Torcasio, R. C.; Montesanti, S.

2015-01-01

of the ECMWF Integrated Forecasting System (IFS), whose horizontal resolution over Central Italy is about 25 km at the time considered in this paper. Because wind observations were not available for the site, the power curve for the whole wind farm was derived from the ECMWF wind operational analyses available......The importance of wind power forecast is commonly recognized because it represents a useful tool for grid integration and facilitates the energy trading. This work considers an example of power forecast for a wind farm in the Apennines in Central Italy. The orography around the site is complex...... and the horizontal resolution of the wind forecast has an important role. To explore this point we compared the performance of two 48 h wind power forecasts using the winds predicted by the Regional Atmospheric Modeling System (RAMS) for the year 2011. The two forecasts differ only for the horizontal resolution...

The Learning Process and Technological Change in Wind Power: Evidence from China's CDM Wind Projects

Science.gov (United States)

Tang, Tian; Popp, David

2016-01-01

The Clean Development Mechanism (CDM) is a project-based carbon trade mechanism that subsidizes the users of climate-friendly technologies and encourages technology transfer. The CDM has provided financial support for a large share of Chinese wind projects since 2002. Using pooled cross-sectional data of 486 registered CDM wind projects in China…

Market integration of wind power in electricity system balancing

DEFF Research Database (Denmark)

Sorknæs, Peter; Andersen, Anders N.; Tang, Jens

2013-01-01

In most countries markets for electricity are divided into wholesale markets on which electricity is traded before the operation hour, and real-time balancing markets to handle the deviations from the wholesale trading. So far, wind power has been sold only on the wholesale market and has been...... known to increase the need for balancing. This article analyses whether wind turbines in the future should participate in the balancing markets and thereby play a proactive role. The analysis is based on a real-life test of proactive participation of a wind farm in West Denmark. It is found...... that the wind farm is able to play a proactive role regarding downward regulation and thereby increase profits....

Wind energy statistics

International Nuclear Information System (INIS)

Holttinen, H.; Tammelin, B.; Hyvoenen, R.

1997-01-01

The recording, analyzing and publishing of statistics of wind energy production has been reorganized in cooperation of VTT Energy, Finnish Meteorological (FMI Energy) and Finnish Wind Energy Association (STY) and supported by the Ministry of Trade and Industry (KTM). VTT Energy has developed a database that contains both monthly data and information on the wind turbines, sites and operators involved. The monthly production figures together with component failure statistics are collected from the operators by VTT Energy, who produces the final wind energy statistics to be published in Tuulensilmae and reported to energy statistics in Finland and abroad (Statistics Finland, Eurostat, IEA). To be able to verify the annual and monthly wind energy potential with average wind energy climate a production index in adopted. The index gives the expected wind energy production at various areas in Finland calculated using real wind speed observations, air density and a power curve for a typical 500 kW-wind turbine. FMI Energy has produced the average figures for four weather stations using the data from 1985-1996, and produces the monthly figures. (orig.)

High Penetrated Wind Farm Impacts on the Electricity Price

DEFF Research Database (Denmark)

Haji Bashi, Mazaher; Yousefi, G. R.; Bak, Claus Leth

2016-01-01

of the high penetrated wind farm integration into electricity markets. Then, stochastic programming approach is employed to compare the volume of trades for a typical wind farm in a high and low wind penetrated market. Although increasing price spikes and volatility was reported in the literature......Energy trading policies, intermittency of wind farm output power, low marginal cost of the production, are the key factors that cause the wind farms to be effective on the electricity price. In this paper, the Danish electricity market is studied as a part of Nord Pool. Considering the completely...... fossil fuel free overview in Danish energy policies, and the currently great share of wind power (more than 100% for some hours) in supplying the load, it is an interesting benchmark for the future electricity markets. Negative prices, price spikes, and price volatility are considered as the main effects...

Wind and Yaw correlation

DEFF Research Database (Denmark)

Kock, Carsten Weber; Vesth, Allan

The report describes measurements carried out on a given turbine and period. The measurements are carried out in accordance to Ref. [1]. A comparison between wind speed and wind direction on the met mast and nacelle wind speed and yaw direction is made in accordance to Ref. [2] and the results...

Wind and Yaw correlation

DEFF Research Database (Denmark)

Kock, Carsten Weber; Vesth, Allan

The report describes measurements carried out on a given turbine and period. The measurements are carried out in accordance to Ref. [1]. A comparison between wind speed and wind direction on the met mast and nacelle wind speed and yaw direction is made in accordance to Ref. [2] and the results ar...

Act locally, trade globally. Emissions trading for climate policy

Energy Technology Data Exchange (ETDEWEB)

none

2005-07-01

Climate policy raises a number of challenges for the energy sector, the most significant being the transition from a high to a low-CO2 energy path in a few decades. Emissions trading has become the instrument of choice to help manage the cost of this transition, whether used at international or at domestic level. Act Locally, Trade Globally, offers an overview of existing trading systems, their mechanisms, and looks into the future of the instrument for limiting greenhouse gas emissions. Are current markets likely to be as efficient as the theory predicts? What is, if any, the role of governments in these markets? Can domestic emissions trading systems be broadened to activities other than large stationary energy uses? Can international emissions trading accommodate potentially diverse types of emissions targets and widely different energy realities across countries? Are there hurdles to linking emissions trading systems based on various design features? Can emissions trading carry the entire burden of climate policy, or will other policy instruments remain necessary? In answering these questions, Act Locally, Trade Globally seeks to provide a complete picture of the future role of emissions trading in climate policy and the energy sector.

Integration of large amounts of wind power. Markets for trading imbalances

Energy Technology Data Exchange (ETDEWEB)

Neimane, Viktoria; Axelsson, Urban [Vattenfall Research and Development AB, Stockholm (Sweden); Gustafsson, Johan; Gustafsson, Kristian [Vattenfall Nordic Generation Management, Stockholm (Sweden); Murray, Robin [Vattenfall Vindkraft AB, Stockholm (Sweden)

2008-07-01

The well-known concerns about wind power are related to its intermittent nature and difficulty to make exact forecasts. The expected increase in balancing and reserve requirements due to wind power has been investigated in several studies. This paper takes the next step in studying integration of large amounts of wind power in Sweden. Several wind power producers' and corresponding balance providers' perspective is taken and their imbalance costs modeled. Larger producers having wind power spread over larger geographical areas will have lower relative costs than producers having their units concentrated within limited geographical area. Possibilities of the wind power producers to reduce the imbalance costs by acting on after sales market are exposed and compared. (orig.)

Air and water trade winds, hurricanes, gulf stream, tsunamis and other striking phenomena

CERN Document Server

Moreau, René

2017-01-01

Air and water are so familiar that we all think we know them. Yet how difficult it remains to predict their behavior, with so many questions butting against the limits of our knowledge. How are cyclones, tornadoes, thunderstorms, tsunamis or floods generated — sometimes causing devastation and death? What will the weather be tomorrow, next week, next summer? This book brings some answers to these questions with a strategy of describing before explaining. Starting by considering air and water in equilibrium (i.e., at rest), it progresses to discuss dynamic phenomena first focusing on large scale structures, such as El Niño or trade winds, then on ever smaller structures, such as low-pressure zones in the atmosphere, clouds, rain, as well as tides and waves. It finishes by describing man-mad e constructions (dams, ports, power plants, etc.) that serve to domesticate our water resources and put them to work for us.  Including over one hundred illustrations and very few equations, most of the�...

Wind and Yaw correlation

DEFF Research Database (Denmark)

Federici, Paolo; Kock, Carsten Weber

The report describes measurements carried out on a given turbine and period. The measurements are carried out in accordance to Ref. [1]. A comparison between wind speed and wind direction on the met mast and nacelle wind speed and yaw direction is made in accordance to Ref. [2] and the results...... are presented on graphs and in a table....

The economic benefit of short-term forecasting for wind energy in the UK electricity market

International Nuclear Information System (INIS)

Barthelmie, R.J.; Murray, F.; Pryor, S.C.

2008-01-01

In the UK market, the total price of renewable electricity is made up of the Renewables Obligation Certificate and the price achieved for the electricity. Accurate forecasting improves the price if electricity is traded via the power exchange. In order to understand the size of wind farm for which short-term forecasting becomes economically viable, we develop a model for wind energy. Simulations were carried out for 2003 electricity prices for different forecast accuracies and strategies. The results indicate that it is possible to increase the price obtained by around pound 5/MWh which is about 14% of the electricity price in 2003 and about 6% of the total price. We show that the economic benefit of using short-term forecasting is also dependant on the accuracy and cost of purchasing the forecast. As the amount of wind energy requiring integration into the grid increases, short-term forecasting becomes more important to both wind farm owners and the transmission/distribution operators. (author)

Superconductivity for Large Scale Wind Turbines

Energy Technology Data Exchange (ETDEWEB)

R. Fair; W. Stautner; M. Douglass; R. Rajput-Ghoshal; M. Moscinski; P. Riley; D. Wagner; J. Kim; S. Hou; F. Lopez; K. Haran; J. Bray; T. Laskaris; J. Rochford; R. Duckworth

2012-10-12

A conceptual design has been completed for a 10MW superconducting direct drive wind turbine generator employing low temperature superconductors for the field winding. Key technology building blocks from the GE Wind and GE Healthcare businesses have been transferred across to the design of this concept machine. Wherever possible, conventional technology and production techniques have been used in order to support the case for commercialization of such a machine. Appendices A and B provide further details of the layout of the machine and the complete specification table for the concept design. Phase 1 of the program has allowed us to understand the trade-offs between the various sub-systems of such a generator and its integration with a wind turbine. A Failure Modes and Effects Analysis (FMEA) and a Technology Readiness Level (TRL) analysis have been completed resulting in the identification of high risk components within the design. The design has been analyzed from a commercial and economic point of view and Cost of Energy (COE) calculations have been carried out with the potential to reduce COE by up to 18% when compared with a permanent magnet direct drive 5MW baseline machine, resulting in a potential COE of 0.075 $/kWh. Finally, a top-level commercialization plan has been proposed to enable this technology to be transitioned to full volume production. The main body of this report will present the design processes employed and the main findings and conclusions.

Wake characteristics of wind turbines in utility-scale wind farms

Science.gov (United States)

Yang, Xiaolei; Foti, Daniel; Sotiropoulos, Fotis

2017-11-01

The dynamics of turbine wakes is affected by turbine operating conditions, ambient atmospheric turbulent flows, and wakes from upwind turbines. Investigations of the wake from a single turbine have been extensively carried out in the literature. Studies on the wake dynamics in utility-scale wind farms are relatively limited. In this work, we employ large-eddy simulation with an actuator surface or actuator line model for turbine blades to investigate the wake dynamics in utility-scale wind farms. Simulations of three wind farms, i.e., the Horns Rev wind farm in Denmark, Pleasant Valley wind farm in Minnesota, and the Vantage wind farm in Washington are carried out. The computed power shows a good agreement with measurements. Analysis of the wake dynamics in the three wind farms is underway and will be presented in the conference. This work was support by Xcel Energy (RD4-13). The computational resources were provided by National Renewable Energy Laboratory.

Wind power - the prospects post-1998

International Nuclear Information System (INIS)

Hartnell, G.

1996-01-01

With the opening of Carno, Europe's largest wind farm, the amount of wind energy installed in the UK now exceeds 230 MW. This puts it third in the league of European countries. Supported by Friends of the Earth, the British Wind Energy Association (BWEA) last month launched a campaign to urge the Government to build upon its support for renewable energy technologies, and to adopt a more ambitious target for wind -to generate 10% of UK electricity by 2025. FoE urged local authorities to take their commitment to sustainable development seriously by supporting sensitively developed wind projects. The BWEA examines the economics for wind power, and assesses the outlook for future trading in green energy. (author)

ewec 2007 - Europe's premier wind energy event

Energy Technology Data Exchange (ETDEWEB)

Chaviaropoulos, T. (ed.)

2007-07-01

This online collection of papers - the ewec 2007 proceedings - reflects the various sessions and lectures presented at the ewec wind-energy convention held in Milan in 2007. The first day's sessions looked at the following topics: Renewable Energy Roadmap, the changing structure of the wind industry, politics and programmes, aerodynamics and innovation in turbine design, wind resources and site characterisation (2 sessions), energy scenarios, harmonisation of incentive schemes, structural design and materials, forecasting, integration studies, integrating wind into electricity markets, wind-turbine electrical systems and components, as well as loads, noise and wakes. The second day included sessions on offshore: developments and prospects, extreme wind conditions and forecasting techniques, small wind turbines, distributed generation and autonomous systems cost effectiveness, cost effectiveness of wind energy, financing wind energy concepts, wind and turbulence, wind power plants and grid integration, offshore technology, global challenges and opportunities, aero-elasticity, loads and control, operations and maintenance, carbon trading and the emission trading schemes, investment strategies of power producers, wind power plants and grid integration, wind turbine electrical systems and components, and wakes. The third day offered sessions on environmental issues, condition monitoring, operation and maintenance, structural design and materials, the Up-Wind workshop, winning hearts and minds, offshore technology, advances in measuring methods and advancing drive-train reliability. In a closing session the conference was summarised, awards for poster contributions were made and the Poul la Cour Prize was presented.

ETUDE - European Trade Union Distance Education.

Science.gov (United States)

Creanor, Linda; Walker, Steve

2000-01-01

Describes transnational distance learning activities among European trade union educators carried out as part of the European Trade Union Distance Education (ETUDE) project, supported by the European Commission. Highlights include the context of international trade union distance education; tutor training course; tutors' experiences; and…

Equilibrium pricing in electricity markets with wind power

Science.gov (United States)

Rubin, Ofir David

Estimates from the World Wind Energy Association assert that world total wind power installed capacity climbed from 18 Gigawatt (GW) to 152 GW from 2000 to 2009. Moreover, according to their predictions, by the end of 2010 global wind power capacity will reach 190 GW. Since electricity is a unique commodity, this remarkable expansion brings forward several key economic questions regarding the integration of significant amount of wind power capacity into deregulated electricity markets. The overall dissertation objective is to develop a comprehensive theoretical framework that enables the modeling of the performance and outcome of wind-integrated electricity markets. This is relevant because the state of knowledge of modeling electricity markets is insufficient for the purpose of wind power considerations. First, there is a need to decide about a consistent representation of deregulated electricity markets. Surprisingly, the related body of literature does not agree on the very economic basics of modeling electricity markets. That is important since we need to capture the fundamentals of electricity markets before we introduce wind power to our study. For example, the structure of the electric industry is a key. If market power is present, the integration of wind power has large consequences on welfare distribution. Since wind power uncertainty changes the dynamics of information it also impacts the ability to manipulate market prices. This is because the quantity supplied by wind energy is not a decision variable. Second, the intermittent spatial nature of wind over a geographical region is important because the market value of wind power capacity is derived from its statistical properties. Once integrated into the market, the distribution of wind will impact the price of electricity produced from conventional sources of energy. Third, although wind power forecasting has improved in recent years, at the time of trading short-term electricity forwards, forecasting

Wind energy and aviation interests - interim guidelines

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-07-01

The impact on aviation of increasing the number of wind farms in the United Kingdom is discussed by the Wind Energy, Defence and Civil Aviation Interests Working Group, comprising the Department of Trade and Industry, the Civil Aviation Authority, the Ministry of Defence, and the British Wind Energy Association. The report offers guidance to wind farm developers, local authorities and statutory consultees within the aviation community: the main thrust of the guidelines is to support the UK Government's wind energy targets. Although the document does not contain in-depth technical discussions, it does provide references to such information.

Fatigue-Damage Estimation and Control for Wind Turbines

OpenAIRE

Barradas Berglind, Jose de Jesus

2015-01-01

How can fatigue-damage for control of wind turbines be represented? Fatigue-damage is indeed a crucial factor in structures such as wind turbines that are exposed to turbulent and rapidly changing wind flow conditions. This is relevant both in their design stage and during the control of their operation. Accordingly, the most recognized methods of fatigue-damage estimation are discussed in this thesis.In wind energy conversion systems there is an intrinsic trade-off between power generation m...

Optimal Placing of Wind Turbines: Modelling the Uncertainty

NARCIS (Netherlands)

Leenman, T.S.; Phillipson, F.

2015-01-01

When looking at the optimal place to locate a wind turbine, trade-offs have to be made between local placement and spreading: transmission loss favours local placements and the correlation between the stochastic productions of wind turbines favours spreading. In this paper steps are described to

Optimal Placing of Wind Turbines: Modelling the Uncertainty

NARCIS (Netherlands)

Leenman, T.S.; Phillipson, F.

2014-01-01

When looking at the optimal place to locate a wind turbine, trade-offs have to be made between local placement and spreading: transmission loss favours local placements and the correlation between the stochastic productions of wind turbines favours spreading. In this paper steps are described to

Wind Turbine Test. Wind Matic WM 17S

DEFF Research Database (Denmark)

Friis Pedersen, Troels

The report describes standard measurements performed on a Wind-Matic WM 17S, 75 kW wind turbine. The measurements carried out and reported here comprises the power output, system efficiency, energy production, transmission efficiency, rotor power, rotor efficiency, air-brakes efficiency, structural...

Wind Turbine Test Wind Matic WM 15S

DEFF Research Database (Denmark)

Friis Pedersen, Troels

The report describes standard measurements performed on a Wind-Matic WM 15S, 55 kW wind turbine. The measurements carried out and reported here comprises the power output, system efficiency, energy production, transmission efficiency, rotor power, rotor efficiency, air-brakes efficiency, dynamical...

Impact of energy trading on O and M and vice versa; Wechselwirkung zwischen Energiehandel und O and M

Energy Technology Data Exchange (ETDEWEB)

Zauner, Rudolf [VERBUND Renewable Power GmbH, Wien (Austria)

2013-11-01

Wind energy is growing up, and in more and more markets is being traded the same as any other energy source. This imposes a number of challenges on the wind turbine operators. However, a comparison of various European countries shows that this is the way forward: a market-oriented subsidiary system is set to replace the inflexible feed-in tariffs. To trade wind energy, wind must be forecast as accurately as possible a day in advance in an at least hourly resolution. This leads to a decrease in balancing energy costs and plays a key role in bringing wind energy closer to the market. (orig.)

Wind power plant

Energy Technology Data Exchange (ETDEWEB)

Caneghem, A.E. von

1975-07-24

The invention applies to a wind power plant in which the wind is used to drive windmills. The plant consists basically of a vertical tube with a lateral wind entrance opening with windmill on its lower end. On its upper end, the tube carries a nozzle-like top which increases the wind entering the tube by pressure decrease. The wind is thus made suitable for higher outputs. The invention is illustrated by constructional examples.

Secondary contamination of 30-km zone of the Chernobyl atomic electric plant and adjacent territory due to radionuclides carried by ascending wind

International Nuclear Information System (INIS)

Garger, E.K.; Gavrilov, V.P.

1992-01-01

The territory contaminated with radionuclides as a result of the accident at the Chernobyl atomic electric plant is a surface source of radioactive aerosols carried into the atmosphere by ascending winds. In this connection, a number of problems arise whose solution is important for assessment of the radiation conditions in the atmosphere near the Earth's surface: (1) calculation of the volume concentration of radionuclides and their fallout on the contaminated and neighboring territory and on this basis determine the potentially dangerous contaminated regions; (2) assessment of the secondary contamination of deactivated territories due to ascending winds and transfer of radionuclides; and (3) determination of the size of the protective (buffer) zones around or near populated areas to ensure low volume concentrations of radionuclides during strong winds. In order to calculate the transfer of radionuclides from a surface source, it is necessary to know its dust intensity, which is the vertical turbulent flux of the radionuclides in the atmosphere layer near the ground Q (Ci · m -2 sec -1 ). A quantity frequently used in practice is Q referred to the contamination density of the surface layer c (Ci/m 2 ) and called the wind ascent intensity α = Q/c. As a rule, the radionuclide wind ascent intensity for a plane source with a nonuniform surface and contamination density may depend on the physical characteristics of the surface as well as on those of the radionuclides and also on the space coordinates x, y and on time. In the present study, the wind ascent intensity was determined by gradient measurements of the mean radionuclide concentration, the wind velocity and air temperature; the conditions during the measurements were assumed to correspond to the case of a plane homogeneous, stationary source of a nondepositing admixture

Forecastability as a Design Criterion in Wind Resource Assessment: Preprint

Energy Technology Data Exchange (ETDEWEB)

Zhang, J.; Hodge, B. M.

2014-04-01

This paper proposes a methodology to include the wind power forecasting ability, or 'forecastability,' of a site as a design criterion in wind resource assessment and wind power plant design stages. The Unrestricted Wind Farm Layout Optimization (UWFLO) methodology is adopted to maximize the capacity factor of a wind power plant. The 1-hour-ahead persistence wind power forecasting method is used to characterize the forecastability of a potential wind power plant, thereby partially quantifying the integration cost. A trade-off between the maximum capacity factor and the forecastability is investigated.

Wind turbine generators having wind assisted cooling systems and cooling methods

Science.gov (United States)

Bagepalli, Bharat [Niskayuna, NY; Barnes, Gary R [Delanson, NY; Gadre, Aniruddha D [Rexford, NY; Jansen, Patrick L [Scotia, NY; Bouchard, Jr., Charles G.; Jarczynski, Emil D [Scotia, NY; Garg, Jivtesh [Cambridge, MA

2008-09-23

A wind generator includes: a nacelle; a hub carried by the nacelle and including at least a pair of wind turbine blades; and an electricity producing generator including a stator and a rotor carried by the nacelle. The rotor is connected to the hub and rotatable in response to wind acting on the blades to rotate the rotor relative to the stator to generate electricity. A cooling system is carried by the nacelle and includes at least one ambient air inlet port opening through a surface of the nacelle downstream of the hub and blades, and a duct for flowing air from the inlet port in a generally upstream direction toward the hub and in cooling relation to the stator.

Progress with the Scottish Trading Arrangements Group (STAG)

International Nuclear Information System (INIS)

Fellows, A.

1998-01-01

Since November 1996 STAG has operated as a forum to allow traders in the Scottish market to consider trading arrangements which will facilitate competition while coping with foreseeable trading requirements beyond the 1998 franchise break. The author has promoted the interest of renewables generators on behalf of the Scottish Renewables Forum throughout this process. An Interim Report summarising the high level options considered was submitted to OFFER in June 1997. This paper summarises the interim report content and draws on other aspects of the Scottish market to review the future prospects in Scotland for trading electricity form wind energy schemes. (Author)

Wind Energy Resource Atlas of Mongolia

Energy Technology Data Exchange (ETDEWEB)

Elliott, D; Schwartz, M; Scott, G.; Haymes, S.; Heimiller, D.; George, R.

2001-08-27

The United States Department of Energy (DOE) and the United States Agency for International Development (USAID) sponsored a project to help accelerate the large-scale use of wind energy technologies in Mongolia through the development of a wind energy resource atlas of Mongolia. DOE's National Renewable Energy Laboratory (NREL) administered and conducted this project in collaboration with USAID and Mongolia. The Mongolian organizations participating in this project were the Scientific, Production, and Trade Corporation for Renewable Energy (REC) and the Institute of Meteorology and Hydrology (IMH). The primary goals of the project were to develop detailed wind resource maps for all regions of Mongolia for a comprehensive wind resource atlas, and to establish a wind-monitoring program to identify prospective sites for wind energy projects and help validate some of the wind resource estimates.

On the Response of a Micro Wind Turbine to Wind-Speed Change

OpenAIRE

烏谷, 隆; 渡辺, 公彦; 大屋, 裕二

2004-01-01

To improve the efficiency of a wind turbine, it is more effective to use high-speed wind. A method collecting wind to get high-speed wind was experimentally studied. It was found that the brimmed diffuser was a good device to get high-speed wind. The brimmed diffuser accelerated approaching wind, and wind speed near its inlet became about 1.7 times. Using this brimmed diffuser, we have made a new micro wind turbine and been carrying out field experiment. In order realize the properties of the...

Investigation on wind turbine wakes: wind tunnel tests and field experiments with LIDARs

Science.gov (United States)

Iungo, Giacomo; Wu, Ting; Cöeffé, Juliette; Porté-Agel, Fernando; WIRE Team

2011-11-01

An investigation on the interaction between atmospheric boundary layer flow and wind turbines is carried out with wind tunnel and LIDAR measurements. The former were carried out using hot-wire anemometry and multi-hole pressure probes in the wake of a three-bladed miniature wind turbine. The wind turbine wake is characterized by a strong velocity defect in the proximity of the rotor, and its recovery is found to depend on the characteristics of the incoming atmospheric boundary layer (mean velocity and turbulence intensity profiles). Field experiments were performed using three wind LIDARs. Bi-dimensional scans are performed in order to analyse the wake wind field with different atmospheric boundary layer conditions. Furthermore, simultaneous measurements with two or three LIDARs allow the reconstruction of multi-component velocity fields. Both LIDAR and wind tunnel measurements highlight an increased turbulence level at the wake boundary for heights comparable to the top-tip of the blades; this flow feature can produce dangerous fatigue loads on following wind turbines.

Wind and Yaw correlation

DEFF Research Database (Denmark)

Kock, Carsten Weber; Vesth, Allan

The report describes measurements carried out on a given wind turbine. A comparison between wind speed on the metmast and Nacelle Windspeed are made and the results are presented on graphs and in a table. The data used for the comparison are identical with the data used for the Risø-I-3246(EN) po......) power curve report. The measurements are carried out in accordance to Ref. [1] and the wind and yaw correlation is analyzed in accordance to Ref. [2]....

Trade promotion of irradiated food

International Nuclear Information System (INIS)

1986-10-01

The meeting carried out by the Group was attended by invited specialists on legislation, marketing, consumer attitudes and industry interested in the application of food irradiation. The major objectives of the meeting were to identify barriers and constraints to trade in irradiated food and to recommend actions to be carried out by the Group to promote trade in such foods. The report of the meeting and selected 9 background papers used at the meeting are presented. A separate abstract was prepared for each of these papers

Wind Resource Assessment – Østerild National Test Centre for Large Wind Turbines

OpenAIRE

Hansen, Brian Ohrbeck; Courtney, Michael; Mortensen, Niels Gylling

2014-01-01

This report presents a wind resource assessment for the seven test stands at the Østerild National Test Centre for Large Wind Turbines in Denmark. Calculations have been carried out mainly using wind data from three on-site wind lidars. The generalized wind climates applied in the wind resource calculations for the seven test stands are based on correlations between a short period of on-site wind data from the wind lidars with a long-term reference. The wind resource assessment for the seven ...

Controller design for a Wind Farm, Considering both Power and Load Aspects

DEFF Research Database (Denmark)

Soleimanzadeh, Maryam; Wisniewski, Rafal

2011-01-01

turbine. The control algorithm determines the reference signals for each individual wind turbine controller in two scenarios based on low and high wind speed. In low wind speed, the reference signals for rotor speed are adjusted, taking the trade-off between power maximization and load minimization...

Energy trading and pricing in microgrids with uncertain energy supply

DEFF Research Database (Denmark)

Ma, Kai; Hu, Shubing; Yang, Jie

2017-01-01

This paper studies an energy trading and pricing problem for microgrids with uncertain energy supply. The energy provider with the renewable energy (RE) generation (wind power) determines the energy purchase from the electricity markets and the pricing strategy for consumers to maximize its profi....... In particular, the uncertainty of the energy supply from the energy provider is considered. Simulation results show that the energy provider can obtain more profit using the proposed decision-making scheme.......This paper studies an energy trading and pricing problem for microgrids with uncertain energy supply. The energy provider with the renewable energy (RE) generation (wind power) determines the energy purchase from the electricity markets and the pricing strategy for consumers to maximize its profit...

20 CFR 404.1095 - Agricultural trade or business.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Agricultural trade or business. 404.1095... Income § 404.1095 Agricultural trade or business. (a) An agricultural trade or business is one in which, if the trade or business were carried on entirely by employees, the major portion of the services...

Maritime vessels carry more than half of growing U.S.-East Africa trade

Science.gov (United States)

2009-03-01

Trade between the United States and East African countries (defined in this special report as Burundi, Kenya, Rwanda, Tanzania, and Uganda) has grown substantially in recent years, reaching $1.3 billion in value in 2007. Between 1997 and 2007, U.S. e...

Wind power plant

Energy Technology Data Exchange (ETDEWEB)

Weiss, G

1975-11-20

A wind power plant is proposed suitable for electicity generation or water pumping. This plant is to be self-adjusting to various wind velocities and to be kept in operation even during violent storms. For this purpose the mast, carrying the wind rotor and pivotable around a horizontal axis is tiltable and equipped with a wind blind. Further claims contain various configurations of the tilting base resp. the cut in of an elastic link, the attachment and design of the wind blind as well as the constructive arrangement of one or more dynamos.

European wood-fuel trade

International Nuclear Information System (INIS)

Hillring, B.; Vinterbaeck, J.

2001-01-01

This paper discusses research carried out during the l990s on European wood fuel trade at the Department of Forest Management and Products, SLU, in Sweden. Utilisation of wood-fuels and other biofuels increased very rapidly in some regions during that period. Biofuels are replacing fossil fuels which is an effective way to reduce the future influence of green house gases on the climate. The results indicate a rapid increase in wood-fuel trade in Europe from low levels and with a limited number of countries involved. The chief products traded are wood pellets, wood chips and recycled wood. The main trading countries are, for export, Germany and the Baltic states and, for import, Sweden, Denmark and to some extent the Netherlands. In the future, the increased use of biofuel in European countries is expected to intensify activity in this trade. (orig.)

Progress in wind tunnel experimental techniques for wind turbine?

Institute of Scientific and Technical Information of China (English)

Jingping XIAO; Li CHEN; Qiang WANG; Qiao WANG

2016-01-01

Based on the unsteady aerodynamics experiment (UAE) phase VI and the model experiment in controlled conditions (MEXICO) projects and the related research carried out in China Aerodynamic Research and Development Center (CARDC), the recent progress in the wind tunnel experimental techniques for the wind turbine is sum-marized. Measurement techniques commonly used for di?erent types of wind tunnel ex-periments for wind turbine are reviewed. Important research achievements are discussed, such as the wind tunnel disturbance, the equivalence of the airfoil in?ow condition, the three-dimensional (3D) e?ect, the dynamic in?ow in?uence, the ?ow ?eld structure, and the vortex induction. The corresponding research at CARDC and some ideas on the large wind turbine are also introduced.

'Wind in motion'. The rough guide to wind energy development

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-07-15

This project, which will run from January 2005 to October 2005, aims to develop a promotional DVD to inform and reassure the public and specific audiences on controversial aspects of proposed new wind farms. The DVD would also be used as a tool to gain acceptance and contributions from bodies involved in wind energy developments. 'Wind in Motion' complements a number of other public relations campaigns being undertaken bor proposed by the Department of Trade and Industry (DTI) and the British Wind Energy Association (BWEA). The DVD would cover issues such as the impact of wind farms of wild birds, the visual impact of wind farms on the landscape, the impact on tourism in scenic areas, the impact of local house prices, the impact on local residents during the construction and operational phases, and comparisons with the capacity and efficiencies of other electricity generating systems such as coal, gas and nuclear. The project's objectives are to facilitate the deployment of wind energy by addressing information barriers and providing information to help industry with transferable skills to diversify in the supply chain. Work will include cataloguing the footage taken for the DVD to allow it to be made available to the industry and producing case studies of the benefits of skills transfer.

A simplified model predicting the weight of the load carrying beam in a wind turbine blade

DEFF Research Database (Denmark)

Mikkelsen, Lars Pilgaard

2016-01-01

from 20 to 90 m. In addition, it can be seen that for a blade using glass fibre reinforced polymers, the design is controlled by the deflection and thereby the material stiffness in order to avoid the blade to hit the tower. On the other hand if using aluminium, the design will be controlled...... to predict the weight of the load carrying beam when using glassfibre reinforced polymers, carbon fibre reinforced polymers or an aluminium alloy as the construction material. Thereby, it is found that the weight of a glass fibre wind turbine blade is increased from 0.5 to 33 tons when the blade length grows...... by the fatigue resistance in orderto making the material survive the 100 to 500 million load cycles experience of the windturbine blade throughout the lifetime. The aluminium blade is also found to be considerably heavier compared with the composite blades....

Integration of wind power in the Danish generation system. EC wind power penetration study, phase 2

Energy Technology Data Exchange (ETDEWEB)

NONE

1989-06-01

The Commission of the European Communities has asked utilities in the member countries to carry out a coordinated study of the wind energy potential. The main objective is to show the consequences for the future electricity system when integrating wind power production covering 5, 10 or 15% of total demand. In addition to the best estimate scenario believed to be operational, some additional calculations have been carried out: wind power production as a negative load only (not operational for the total system); different levels of investment in wind farms. The methodology is based on the following steps: define a reference scenario for year 2000; define an alternative scenario with a certain amount of wind power production; calculate time-series for electrical load and district heating from combined heat/power production; calculate time-series for wind power production; make economic evaluation and sensitivity analysis; show environmental differences. Incorporation of wind power into the ELSAM power system, with the wind energy meeting, about 5% of demand will give rise to additional control capacity, or call for new contracts with neighbouring countries. The study includes estimated network investments. The simulations have been made with the SIM and SLUMP computer programmes. The economic analyses and the sensitivity analyses have been carried out using spreadsheets. The conclusion concerning profitability - based on the best estimate assumptions - is that the studied wind power scenarios are unprofitable. (EG)

Investigation of Wind Turbine Rotor Concepts for Offshore Wind Farms

International Nuclear Information System (INIS)

Ceyhan, Özlem; Grasso, Francesco

2014-01-01

Current plans in offshore wind energy developments call for further reduction of cost of energy. In order to contribute to this goal, several wind turbine rotor concepts have been investigated. Assuming the future offshore wind turbines will operate only in the offshore wind farms, the rotor concepts are not only evaluated for their stand-alone performances and their potential in reducing the loads, but also for their performance in an offshore wind farm. In order to do that, the 10MW reference wind turbine designed in Innwind.EU project is chosen as baseline. Several rotor parameters have been modified and their influences are investigated for offshore wind turbine design purposes. This investigation is carried out as a conceptual parametrical study. All concepts are evaluated numerically with BOT (Blade optimisation tool) software in wind turbine level and with Farmflow software in wind farm level for two wind farm layouts. At the end, all these concepts are compared with each other in terms of their advantages and disadvantages

IMPER: Characterization of the wind field over a large wind turbine rotor - final report; Improved performance

Energy Technology Data Exchange (ETDEWEB)

Schmidt Paulsen, U.; Wagner, R.

2012-01-15

A modern wind turbine rotor with a contemporary rotor size would easily with the tips penetrate the air between 116 m and 30 m and herby experience effects of different wind. With current rules on power performance measurements such as IEC 61400-121 the reference wind speed is measured at hub height, an oversimplification of the wind energy power over the rotor disk area is carried out. The project comprised a number of innovative and coordinated measurements on a full scale turbine with remote sensing technology and simulations on a 500 kW wind turbine for the effects of wind field characterization. The objective with the present report is to give a short overview of the different experiments carried out and results obtained within the final phase of this project. (Author)

The choice of strategic trade policy in China under the WTO frame

Institute of Scientific and Technical Information of China (English)

陆长春; 唐丹; 王新辉; 张德晖

2007-01-01

This text first elaborated the core thought and apply condition of the strategic trade policy first;secondly Put the strategic trade policy and WTO rule together to carry on analysis;finally,Combine the concrete circumstance of China,Put forward several suggestions on carrying out a strategic trade policy under the WTO frame。

Interconnector capacity allocation in offshore grids with variable wind generation

DEFF Research Database (Denmark)

Schröder, Sascha Thorsten

2013-01-01

the interconnector capacity should be allocated for wind generation and for international power trading. The main difficulty arises from the stochastic nature of wind generation: in a case with radial connections to the national coast, the wind park owner has the possibility of aggregating the offshore wind park....... It is concluded that treating offshore generation as a single price zone within the interconnector reduces the wind operator’s ability to pool it with other generation. Furthermore, a single offshore price zone between two markets will always receive the lower spot market price of the neighbouring zones, although...

Evaluation of Nonparametric Probabilistic Forecasts of Wind Power

DEFF Research Database (Denmark)

Pinson, Pierre; Møller, Jan Kloppenborg; Nielsen, Henrik Aalborg, orlov 31.07.2008

Predictions of wind power production for horizons up to 48-72 hour ahead comprise a highly valuable input to the methods for the daily management or trading of wind generation. Today, users of wind power predictions are not only provided with point predictions, which are estimates of the most...... likely outcome for each look-ahead time, but also with uncertainty estimates given by probabilistic forecasts. In order to avoid assumptions on the shape of predictive distributions, these probabilistic predictions are produced from nonparametric methods, and then take the form of a single or a set...

78 FR 11146 - Utility Scale Wind Towers From the People's Republic of China: Antidumping Duty Order

Science.gov (United States)

2013-02-15

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-981] Utility Scale Wind Towers...''), the Department is issuing an antidumping duty order on utility scale wind towers (``wind towers...) 482-3936, or (202) 482-4852, respectively. SUPPLEMENTARY INFORMATION: Background In accordance with...

Wind Predictions Upstream Wind Turbines from a LiDAR Database

Directory of Open Access Journals (Sweden)

Soledad Le Clainche

2018-03-01

Full Text Available This article presents a new method to predict the wind velocity upstream a horizontal axis wind turbine from a set of light detection and ranging (LiDAR measurements. The method uses higher order dynamic mode decomposition (HODMD to construct a reduced order model (ROM that can be extrapolated in space. LiDAR measurements have been carried out upstream a wind turbine at six different planes perpendicular to the wind turbine axis. This new HODMD-based ROM predicts with high accuracy the wind velocity during a timespan of 24 h in a plane of measurements that is more than 225 m far away from the wind turbine. Moreover, the technique introduced is general and obtained with an almost negligible computational cost. This fact makes it possible to extend its application to both vertical axis wind turbines and real-time operation.

Performance of spanish wind turbines

International Nuclear Information System (INIS)

Lago, C.

1995-01-01

In this document we can find a statistical evaluation for the wind energy generation from each spanish wind farm referred to 1994, going on with the work that has been carried out since 1992, by initiative of the Wind Energy Division from Renewable Energy Institute. The purpose of this work is to contribute with interesting information for the wind environment and offer a global view from monthly performances of different wind farms. (Author)

Trading green electricity

International Nuclear Information System (INIS)

Davies, M.

1997-01-01

A study has been carried out into the feasibility of developing an electricity trading mechanism which would allow consumers to purchase electricity which has been derived from renewable energy resources. This study was part funded by the European Commission (ALTENER), the Department of Trade and Industry and a number of private sector companies. The trading mechanism is known as the Green Pool. As a result of the findings of this study discussions are being held with potential generators and suppliers to establish a Green Pool plc. The aim is to encourage the development of new renewable energy projects outside the NFFO and SRO schemes. The Green Pool plc will be owned by the generators and its main objective will be to market the electricity produced by its members. (Author)

An Appropriate Wind Model for Wind Integrated Power Systems Reliability Evaluation Considering Wind Speed Correlations

Directory of Open Access Journals (Sweden)

Rajesh Karki

2013-02-01

Full Text Available Adverse environmental impacts of carbon emissions are causing increasing concerns to the general public throughout the world. Electric energy generation from conventional energy sources is considered to be a major contributor to these harmful emissions. High emphasis is therefore being given to green alternatives of energy, such as wind and solar. Wind energy is being perceived as a promising alternative. This source of energy technology and its applications have undergone significant research and development over the past decade. As a result, many modern power systems include a significant portion of power generation from wind energy sources. The impact of wind generation on the overall system performance increases substantially as wind penetration in power systems continues to increase to relatively high levels. It becomes increasingly important to accurately model the wind behavior, the interaction with other wind sources and conventional sources, and incorporate the characteristics of the energy demand in order to carry out a realistic evaluation of system reliability. Power systems with high wind penetrations are often connected to multiple wind farms at different geographic locations. Wind speed correlations between the different wind farms largely affect the total wind power generation characteristics of such systems, and therefore should be an important parameter in the wind modeling process. This paper evaluates the effect of the correlation between multiple wind farms on the adequacy indices of wind-integrated systems. The paper also proposes a simple and appropriate probabilistic analytical model that incorporates wind correlations, and can be used for adequacy evaluation of multiple wind-integrated systems.

Wind Power Prediction using Ensembles

DEFF Research Database (Denmark)

Giebel, Gregor; Badger, Jake; Landberg, Lars

2005-01-01

offshore wind farm and the whole Jutland/Funen area. The utilities used these forecasts for maintenance planning, fuel consumption estimates and over-the-weekend trading on the Leipzig power exchange. Othernotable scientific results include the better accuracy of forecasts made up from a simple...... superposition of two NWP provider (in our case, DMI and DWD), an investigation of the merits of a parameterisation of the turbulent kinetic energy within thedelivered wind speed forecasts, and the finding that a “naïve” downscaling of each of the coarse ECMWF ensemble members with higher resolution HIRLAM did...

Are the British electricity trading and transmission arrangements future-proof?

International Nuclear Information System (INIS)

Green, Richard

2010-01-01

In Great Britain, electricity is traded in an energy-only market that relies upon bilateral trading until shortly before real time. The GB System Operator also uses bilateral trading to respond to changes in demand and generation and resolve transmission constraints. Prices are not explicitly spatial, although well-placed generators can charge the system operator more for their output. This paper argues that these arrangements are not well-suited for the challenges of accommodating nearly thirty percent of intermittent wind generation, often located far from demand. The market design already implemented in the north-eastern United States is likely to be more efficient. (author)

Cost of wind energy: comparing distant wind resources to local resources in the midwestern United States.

Science.gov (United States)

Hoppock, David C; Patiño-Echeverri, Dalia

2010-11-15

The best wind sites in the United States are often located far from electricity demand centers and lack transmission access. Local sites that have lower quality wind resources but do not require as much power transmission capacity are an alternative to distant wind resources. In this paper, we explore the trade-offs between developing new wind generation at local sites and installing wind farms at remote sites. We first examine the general relationship between the high capital costs required for local wind development and the relatively lower capital costs required to install a wind farm capable of generating the same electrical output at a remote site,with the results representing the maximum amount an investor should be willing to pay for transmission access. We suggest that this analysis can be used as a first step in comparing potential wind resources to meet a state renewable portfolio standard (RPS). To illustrate, we compare the cost of local wind (∼50 km from the load) to the cost of distant wind requiring new transmission (∼550-750 km from the load) to meet the Illinois RPS. We find that local, lower capacity factor wind sites are the lowest cost option for meeting the Illinois RPS if new long distance transmission is required to access distant, higher capacity factor wind resources. If higher capacity wind sites can be connected to the existing grid at minimal cost, in many cases they will have lower costs.

Analysis of a wind farm's revenue in the British and Spanish markets

International Nuclear Information System (INIS)

Angarita-Marquez, Jorge L.; Hernandez-Aramburo, Carlos A.; Usaola-Garcia, Julio

2007-01-01

The composition of the revenue of a wind generation company (WGENCO) under two different European markets is estimated in this paper. The two markets under consideration (British and Spanish) have a very different structure; the Spanish market is a pool-based system while the British market encourages bilateral trading. These markets have also different ways to provide incentives to wind farms, and deal with the trading imbalances to which they are particularly susceptible given the variability of the resource. All these conditions are explained and accounted for in our study of a hypothetical WGENCO that can participate in the two markets. Real wind profiles, two wind-speed forecasting tools and market rules and conditions are used to estimate the WGENCO's revenue over a period of 3 months. Our results show that the net revenue would have been fairly similar under the two market structures; however, the composition of this revenue shows significant differences in terms of renewable incentives and generation revenue

Wind energy in offshore grids

DEFF Research Database (Denmark)

Schröder, Sascha Thorsten

special characteristics of offshore grids. With an operational real options approach, it is furthermore illustrated how different support schemes and connections to additional countries affect the investment case of an offshore wind farm and the income of the transmission system operator. The investment...... and investment implications under different regulatory frameworks are a hitherto underrepresented research field. They are addressed by this thesis. Offshore grids between several countries combine the absorption of wind energy with international power trading. However, the inclusion into an offshore grid......This cumulative PhD thesis deals with wind integration in offshore grids from an economic point of view. It is composed of a generic part and eight papers. As the topic has mostly been analysed with a focus on topology and technical issues until now, market-operational questions in offshore grids...

Wind energy potential assessment of Cameroon's coastal regions for the installation of an onshore wind farm.

Science.gov (United States)

Arreyndip, Nkongho Ayuketang; Joseph, Ebobenow; David, Afungchui

2016-11-01

For the future installation of a wind farm in Cameroon, the wind energy potentials of three of Cameroon's coastal cities (Kribi, Douala and Limbe) are assessed using NASA average monthly wind data for 31 years (1983-2013) and compared through Weibull statistics. The Weibull parameters are estimated by the method of maximum likelihood, the mean power densities, the maximum energy carrying wind speeds and the most probable wind speeds are also calculated and compared over these three cities. Finally, the cumulative wind speed distributions over the wet and dry seasons are also analyzed. The results show that the shape and scale parameters for Kribi, Douala and Limbe are 2.9 and 2.8, 3.9 and 1.8 and 3.08 and 2.58, respectively. The mean power densities through Weibull analysis for Kribi, Douala and Limbe are 33.7 W/m2, 8.0 W/m2 and 25.42 W/m2, respectively. Kribi's most probable wind speed and maximum energy carrying wind speed was found to be 2.42 m/s and 3.35 m/s, 2.27 m/s and 3.03 m/s for Limbe and 1.67 m/s and 2.0 m/s for Douala, respectively. Analysis of the wind speed and hence power distribution over the wet and dry seasons shows that in the wet season, August is the windiest month for Douala and Limbe while September is the windiest month for Kribi while in the dry season, March is the windiest month for Douala and Limbe while February is the windiest month for Kribi. In terms of mean power density, most probable wind speed and wind speed carrying maximum energy, Kribi shows to be the best site for the installation of a wind farm. Generally, the wind speeds at all three locations seem quite low, average wind speeds of all the three studied locations fall below 4.0m/s which is far below the cut-in wind speed of many modern wind turbines. However we recommend the use of low cut-in speed wind turbines like the Savonius for stand alone low energy needs.

Modelling the economics of combined wind/hydro/diesel power systems

International Nuclear Information System (INIS)

Sinha, A.

1993-01-01

A model that stimulates the performance and economics of a combined wind/hydro/diesel plant with pumped storage has been developed. It is applied to a hypothetical site to demonstrate how a subset of the cheapest configuration of plant sizes may be identified, illustrating in particular the trade-off between the hydro storage capacity and the wind turbine penetration. It seems that, with the wind and water regimes employed, pumped storage is unlikely to have significant benefits, but may be beneficial in areas without natural inflow, in which case the reservoir is used as a store for excess wind output. (author)

Validation of wind loading codes by experiments

NARCIS (Netherlands)

Geurts, C.P.W.

1998-01-01

Between 1994 and 1997, full scale measurements of the wind and wind induced pressures were carried out on the main building of Eindhoven University of Technology. Simultaneously, a comparative wind tunnel experiment was performed in an atmospheric boundary layer wind tunnel. In this paper, the

Distributed Model Predictive Control for Active Power Control of Wind Farm

DEFF Research Database (Denmark)

Zhao, Haoran; Wu, Qiuwei; Rasmussen, Claus Nygaard

2014-01-01

This paper presents the active power control of a wind farm using the Distributed Model Predictive Controller (D- MPC) via dual decomposition. Different from the conventional centralized wind farm control, multiple objectives such as power reference tracking performance and wind turbine load can...... be considered to achieve a trade-off between them. Additionally, D- MPC is based on communication among the subsystems. Through the interaction among the neighboring subsystems, the global optimization could be achieved, which significantly reduces the computation burden. It is suitable for the modern large......-scale wind farm control....

Integrated simulation challenges with the DeepWind floating vertical axis wind turbine concept

DEFF Research Database (Denmark)

Verelst, David; Aagaard Madsen, Helge; Borg, Michael

2015-01-01

This paper presents the experiences and challenges with concurrently carrying out numerical model development, integrated simulations and design of a novel floating vertical axis wind turbine, the DeepWind concept. The floating VAWT modelling capabilities of the aero-hydro-elastic HAWC2 simulation...

Scheduling whole-air samples above the Trade Wind Inversion from SUAS using real-time sensors

Science.gov (United States)

Freer, J. E.; Greatwood, C.; Thomas, R.; Richardson, T.; Brownlow, R.; Lowry, D.; MacKenzie, A. R.; Nisbet, E. G.

2015-12-01

Small Unmanned Air Systems (SUAS) are increasingly being used in science applications for a range of applications. Here we explore their use to schedule the sampling of air masses up to 2.5km above ground using computer controlled bespoked Octocopter platforms. Whole-air sampling is targeted above, within and below the Trade Wind Inversion (TWI). On-board sensors profiled the TWI characteristics in real time on ascent and, hence, guided the altitudes at which samples were taken on descent. The science driver for this research is investigation of the Southern Methane Anomaly and, more broadly, the hemispheric-scale transport of long-lived atmospheric tracers in the remote troposphere. Here we focus on the practical application of SUAS for this purpose. Highlighting the need for mission planning, computer control, onboard sensors and logistics in deploying such technologies for out of line-of-sight applications. We show how such a platform can be deployed successfully, resulting in some 60 sampling flights within a 10 day period. Challenges remain regarding the deployment of such platforms routinely and cost-effectively, particularly regarding training and support. We present some initial results from the methane sampling and its implication for exploring and understanding the Southern Methane Anomaly.

Optimal electricity market for wind power

International Nuclear Information System (INIS)

Holttinen, H.

2005-01-01

This paper is about electricity market operation when looking from the wind power producers' point of view. The focus in on market time horizons: how many hours there is between the closing and delivering the bids. The case is for the Nordic countries, the Nordpool electricity market and the Danish wind power production. Real data from year 2001 was used to study the benefits of a more flexible market to wind power producer. As a result of reduced regulating market costs from better hourly predictions to the market, wind power producer would gain up to 8% more if the time between market bids and delivery was shortened from the day ahead Elspot market (hourly bids by noon for 12-36 h ahead). An after sales market where surplus or deficit production could be traded 2 h before delivery could benefit the producer almost as much, gaining 7%

Wind energy potential assessment of Cameroon’s coastal regions for the installation of an onshore wind farm

Directory of Open Access Journals (Sweden)

Nkongho Ayuketang Arreyndip

2016-11-01

Full Text Available For the future installation of a wind farm in Cameroon, the wind energy potentials of three of Cameroon’s coastal cities (Kribi, Douala and Limbe are assessed using NASA average monthly wind data for 31 years (1983–2013 and compared through Weibull statistics. The Weibull parameters are estimated by the method of maximum likelihood, the mean power densities, the maximum energy carrying wind speeds and the most probable wind speeds are also calculated and compared over these three cities. Finally, the cumulative wind speed distributions over the wet and dry seasons are also analyzed. The results show that the shape and scale parameters for Kribi, Douala and Limbe are 2.9 and 2.8, 3.9 and 1.8 and 3.08 and 2.58, respectively. The mean power densities through Weibull analysis for Kribi, Douala and Limbe are 33.7 W/m2, 8.0 W/m2 and 25.42 W/m2, respectively. Kribi’s most probable wind speed and maximum energy carrying wind speed was found to be 2.42 m/s and 3.35 m/s, 2.27 m/s and 3.03 m/s for Limbe and 1.67 m/s and 2.0 m/s for Douala, respectively. Analysis of the wind speed and hence power distribution over the wet and dry seasons shows that in the wet season, August is the windiest month for Douala and Limbe while September is the windiest month for Kribi while in the dry season, March is the windiest month for Douala and Limbe while February is the windiest month for Kribi. In terms of mean power density, most probable wind speed and wind speed carrying maximum energy, Kribi shows to be the best site for the installation of a wind farm. Generally, the wind speeds at all three locations seem quite low, average wind speeds of all the three studied locations fall below 4.0m/s which is far below the cut-in wind speed of many modern wind turbines. However we recommend the use of low cut-in speed wind turbines like the Savonius for stand alone low energy needs

Wind turbine cost of electricity and capacity factor

International Nuclear Information System (INIS)

Cavallo, A.J.

1995-01-01

Wind turbines are currently designed to minimize the cost of electricity at the wind turbine (the busbar cost) in a given wind regime, ignoring constraints on the capacitor factor (the ratio of the average power output to the maximum power output). The trade-off between these two quantities can be examined in a straightforward fashion; it is found that the capacitor factor can be increased by a factor of 1.3 above its value at the cost minimum for a 10 percent increase in the cost of electricity. This has important implications for the large scale integration of wind electricity on utility grids where the cost of transmission and storage may be a significant fraction of the cost of delivered electricity. (Author)

Energy from biomass. Summaries of the Biomass Projects carried out as part of the Department of Trade and Industry`s New and Renewable Energy Programme. Vol. 4: anaerobic digestion for biogas

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-12-01

These volumes of summaries provide easy access to the many projects carried out in the Energy from Biomass programme area as part of the Department of Trade and Industry`s New and Renewable Energy Programme. The summaries in this volume cover contractor reports on the subject published up to December 1997. (author)

Skill forecasting from ensemble predictions of wind power

DEFF Research Database (Denmark)

Pinson, Pierre; Nielsen, Henrik Aalborg; Madsen, Henrik

2009-01-01

Optimal management and trading of wind generation calls for the providing of uncertainty estimates along with the commonly provided short-term wind power point predictions. Alternative approaches for the use of probabilistic forecasting are introduced. More precisely, focus is given to prediction...... risk indices aiming to give a comprehensive signal on the expected level of forecast uncertainty. Ensemble predictions of wind generation are used as input. A proposal for the definition of prediction risk indices is given. Such skill forecasts are based on the spread of ensemble forecasts (i.e. a set...... of alternative scenarios for the coming period) for a single prediction horizon or over a took-ahead period. It is shown on the test case of a Danish offshore wind farm how these prediction risk indices may be related to several levels of forecast uncertainty (and potential energy imbalances). Wind power...

Possibilities for wind energy on the Kola peninsula

Energy Technology Data Exchange (ETDEWEB)

Wolff, J; Rathmann, O; Lundsager, P [and others

1999-03-01

This paper presents an extensive feasibility study regarding the introduction of wind energy in the energy supply of the Kola peninsula in north-western Russia that was carried out during 1996-97. The study covers as well grid connected wind turbines as autonomous systems and a wind atlas was prepared. Special emphasis is put on non-technical activities and objectives like financing models, international funding and a sound politic support. The wind resources on the Kola peninsula are excellent and there are still no reasons to why wind energy installations couldn`t be carried out successfully. Recommendations for starting this development are presented. (au)

Study of the costs of offshore wind generation: a report to the Renewables Advisory Board and DTI (Dept. of Trade and Industry)

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-03-12

This study was commissioned by the Department of Trade and Industry (DTI) to provide an estimation of the future costs of offshore wind generation, and the potential for cost reductions in the future. Currently, given the strong market demand for wind turbines and cables, project costs are rising for an industry that is already borderline in terms of economical viability. Hence, the industry and the Government needs to be convinced that there is potential to make this industry more economically attractive and to ensure that it is able to contribute to meet future UK targets of energy from renewable sources. The focus of this report is on the Offshore Design Engineering Ltd. (ODE) Offshore Wind Farm Cost Model, which was specifically developed to allow specific estimates of future wind generation costs to be produced and to allow the user to carry out 'what if' scenarios for changes in the primary trends. Following extensive research six parameters were identified has having the most significant effect on overall project costs. Those are supply and demand, steel costs, copper costs, the effect of learning, research and development and supply and demand of turbines. These trends have been developed based on, where applicable, historical data, previous study work and an extensive Industry Research carried out by ODE. Three trend lines were identified for each trend, a normalised trend line which ODE perceived would be the most likely, and an upper and lower bound. The cost model is based on a level 2 schedule with calculated and fixed costs and durations to individual activities. These costs and durations have been based on information garnered from representatives right across the industry from developers to financiers to cable manufacturers to installation contractors. In parallel with the cost model, a structural study was run with the aim of identifying foundation weights with varying water depths and soil types. It was determined that the monopile, the

Recommendation for an administrative procedure for certification and licensing of wind turbines

Energy Technology Data Exchange (ETDEWEB)

Harvoee, P.; Hjuler Jensen, P. (eds.)

1986-10-15

The lack of existing rules concerning the setting up of wind turbines makes it possible to establish common standards and certification rules for wind turbines in the whole EEC market. Free trade within EEC is necessary if a European wind turbine industry is to enjoy a fair share of the large global market which is anticipated. The report suggests the setting up of national test stations for certifying wind tubines in the EEC-countries and by cooperation between these test centres to create common certification rules. A draft for this procedure is given.

Prediction of Wind Energy Resources (PoWER) Users Guide

Science.gov (United States)

2016-01-01

ARL-TR-7573● JAN 2016 US Army Research Laboratory Prediction of Wind Energy Resources (PoWER) User’s Guide by David P Sauter...manufacturer’s or trade names does not constitute an official endorsement or approval of the use thereof. Destroy this report when it is no longer needed. Do...not return it to the originator. ARL-TR-7573 ● JAN 2016 US Army Research Laboratory Prediction of Wind Energy Resources (PoWER

26 CFR 1.1402(c)-1 - Trade or business.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 12 2010-04-01 2010-04-01 false Trade or business. 1.1402(c)-1 Section 1.1402(c... (CONTINUED) INCOME TAXES Tax on Self-Employment Income § 1.1402(c)-1 Trade or business. In order for an individual to have net earnings from self-employment, he must carry on a trade or business, either as an...

An Optimization Framework for Load and Power Distribution in Wind Farms

DEFF Research Database (Denmark)

Soleimanzadeh, Maryam; Wisniewski, Rafal; Kanev, Stoyan

2012-01-01

The aim of this paper is to develop a controller for wind farms to optimize the load and power distribution. In this regard, the farm controller calculates the power reference signals for individual wind turbine controllers such that the sum of the power references tracks the power demanded...... by a system operator. Moreover, the reference signals are determined to reduce the load acting on wind turbines at low frequencies. Therefore, a trade-off is made for load and power control, which is formulated as an optimization problem. Afterwards, the optimization problem for the wind farm modeled...

Proceedings of the 20. annual CanWEA conference and trade show

International Nuclear Information System (INIS)

2000-01-01

Wind energy is the most competitive large-scale electricity alternative to hydro-electricity and natural gas. Approximately 10,000 MW of wind energy energy may be required in order to meet demand in Canada by 2010. This annual conference provided a forum for decision-makers, industry leaders, power marketers, and regulatory administrators to discuss methods of meeting Canada's future energy supplies. Financial and industrial challenges to the growth of the wind power industry were discussed. Market drivers for wind development in Canada were reviewed, as well as the global status of the wind power industry. Technological advances in wind power were assessed, and issues related to grid integration and reliability were discussed. The conference was divided into 3 sessions: (1) global status and future prospects; (2) the Canadian challenge and opportunity; and (3) the Canadian Wind Energy Association annual general meeting. The conference included a trade show with exhibitions of new technologies related to wind power. The conference featured 31 presentations, of which 3 have been catalogued separately for inclusion in this database. refs., tabs., figs

Wind Turbine Contingency Control Through Generator De-Rating

Science.gov (United States)

Frost, Susan; Goebel, Kai; Balas, Mark

2013-01-01

Maximizing turbine up-time and reducing maintenance costs are key technology drivers for wind turbine operators. Components within wind turbines are subject to considerable stresses due to unpredictable environmental conditions resulting from rapidly changing local dynamics. In that context, systems health management has the aim to assess the state-of-health of components within a wind turbine, to estimate remaining life, and to aid in autonomous decision-making to minimize damage to the turbine. Advanced contingency control is one way to enable autonomous decision-making by providing the mechanism to enable safe and efficient turbine operation. The work reported herein explores the integration of condition monitoring of wind turbines with contingency control to balance the trade-offs between maintaining system health and energy capture. The contingency control involves de-rating the generator operating point to achieve reduced loads on the wind turbine. Results are demonstrated using a high fidelity simulator of a utility-scale wind turbine.

Wind turbines in your environment? Wind turbines and economic aspects

International Nuclear Information System (INIS)

2002-02-01

The wind energy industry has demonstrated its maturity and technical reliability. Because it will play an increasing role on the power generation market, the question of the cost and profitability of the wind energy has become of prime importance. Two main traps must be avoided: the first should be to deny the present and future economical interest of wind energy because of its supplementary cost with respect to conventional power generation techniques. The second trap should be to underestimate the economical progresses that wind energy must carry on to ensure its large scale development. Therefore, some advantageous pricing and regulatory conditions are necessary to allow the development of this emerging energy source. This document presents: the cost of a wind power project (initial investment, financial incentives); the profitability of a project (cost of a kWh of wind power origin, retail price, warranty of power supply capacity, indirect environmental costs, value of decentralized production); economical interest of wind power (energy efficiency, employment, financial advantages for the local economy); and who are the investors. (J.S.)

Wind offering in energy and reserve markets

Science.gov (United States)

Soares, T.; Pinson, P.; Morais, H.

2016-09-01

The increasing penetration of wind generation in power systems to fulfil the ambitious European targets will make wind power producers to play an even more important role in the future power system. Wind power producers are being incentivized to participate in reserve markets to increase their revenue, since currently wind turbine/farm technologies allow them to provide ancillary services. Thus, wind power producers are to develop offering strategies for participation in both energy and reserve markets, accounting for market rules, while ensuring optimal revenue. We consider a proportional offering strategy to optimally decide upon participation in both markets by maximizing expected revenue from day-ahead decisions while accounting for estimated regulation costs for failing to provide the services. An evaluation of considering the same proportional splitting of energy and reserve in both day- ahead and balancing market is performed. A set of numerical examples illustrate the behavior of such strategy. An important conclusion is that the optimal split of the available wind power between energy and reserve strongly depends upon prices and penalties on both market trading floors.

Trade Services System Adaptation for Sustainable Development

Science.gov (United States)

Khrichenkov, A.; Shaufler, V.; Bannikova, L.

2017-11-01

Under market conditions, the trade services system in post-Soviet Russia, being one of the most important city infrastructures, loses its systematic and hierarchic consistency hence provoking the degradation of communicating transport systems and urban planning framework. This article describes the results of the research carried out to identify objects and object parameters that influence functioning of a locally significant trade services system. Based on the revealed consumer behaviour patterns, we propose methods to determine the optimal parameters of objects inside a locally significant trade services system.

A Wind Farm Controller for Load and Power Optimization in a Farm

DEFF Research Database (Denmark)

Soleimanzadeh, Maryam; Brand, Arno; Wisniewski, Rafal

2011-01-01

This paper describes the design procedure of an optimal wind farm controller. The controller optimizes the structural load and power production simultaneously, on the basis of an analytical wind farm model. The farm model delivers maps of wind, loads and energy in the wind farm. Moreover, the model...... computes the wind speed at the turbines, turbine bending moments and aerodynamic power and torque. The optimal control problem is formulated based on the model for two different wind directions. The controller determines the reference signals for each individual wind turbine controller in two scenarios...... based on low and high wind speed. In low wind speed, the reference signals for rotor speed are adjusted, taking the trade-off between power maximization and load minimization into account. In high wind speed, the power and pitch angle reference signals are determined while structural loads are minimized....

Current limiting characteristics of transformer type SFCL with coupled secondary windings according to its winding direction

Energy Technology Data Exchange (ETDEWEB)

Lim, Sung Hun [Dept. of Electrical Engineering, Soongsil University, Seoul (Korea, Republic of); Han, Tae Hee [Dept. of Aero Materials Engineering, Jungwon University, Goesan (Korea, Republic of)

2017-06-15

In this paper, the current limiting characteristics of the transformer type superconducting fault current limiter (SFCL) with the two coupled secondary windings due to its winding direction were analyzed. To analyze the dependence of transient fault current limiting characteristics on the winding direction of the additional secondary winding, the fault current limiting tests of the SFCL with an additional secondary winding, wound as subtractive polarity winding and additive polarity winding, were carried out. The time interval of quench occurrence between two superconducting elements comprising the transformer type SFCL with the additional secondary winding was confirmed to be affected by the winding direction of the additional secondary winding. In case of the subtractive polarity winding of the additional secondary winding, the time interval of the quench occurrence in two superconducting elements was shorter than the case of the additive polarity winding.

Current limiting characteristics of transformer type SFCL with coupled secondary windings according to its winding direction

International Nuclear Information System (INIS)

Lim, Sung Hun; Han, Tae Hee

2017-01-01

In this paper, the current limiting characteristics of the transformer type superconducting fault current limiter (SFCL) with the two coupled secondary windings due to its winding direction were analyzed. To analyze the dependence of transient fault current limiting characteristics on the winding direction of the additional secondary winding, the fault current limiting tests of the SFCL with an additional secondary winding, wound as subtractive polarity winding and additive polarity winding, were carried out. The time interval of quench occurrence between two superconducting elements comprising the transformer type SFCL with the additional secondary winding was confirmed to be affected by the winding direction of the additional secondary winding. In case of the subtractive polarity winding of the additional secondary winding, the time interval of the quench occurrence in two superconducting elements was shorter than the case of the additive polarity winding

System and market integration of wind power in Denmark

DEFF Research Database (Denmark)

Lund, Henrik; Hvelplund, Frede; Alberg Østergaard, Poul

2013-01-01

Denmark has more than 10 years’ of experience with a wind share of approximately 20 per cent. During these 10 years, electricity markets have been subject to developments with a key focus on integrating wind power as well as trading electricity with neighbouring countries. This article introduces...... a methodology to analyse and understand the current market integration of wind power and concludes that the majority of Danish wind power in the period 2004e2008 was used to meet the domestic demand. Based on a physical analysis, at least 63 per cent of Danish wind power was used domestically in 2008....... To analyse the remaining 37 per cent, we must apply a market model to identify cause-effect relationships. The Danish case does not illustrate any upper limit for wind power integration, as also illustrated by Danish political targets to integrate 50 per cent by 2020. In recent years, Danish wind power has...

Estimation of the Possible Power of a Wind Farm

DEFF Research Database (Denmark)

Mirzaei, Mahmood; Göçmen Bozkurt, Tuhfe; Giebel, Gregor

2014-01-01

the possible power calculated based on the estimated effective wind speed of a down regulated wind farm (the industry standard) is compared against the calculated possible power based on the algorithm presented in the paper. The latter takes into account the eect of the wakes of down regulated turbines......It seems possible to increase competitiveness of wind power plants by offering grid services (also called ancillary services) and enter the wind power plants into the ancillary market. One of the ancillary services is called reserve power, the differential capacity between the generated power...... and the available power in the farm. The total amount of energy that a wind farm can potentially generate is called possible power. It is very important for a wind farm owner to have a relatively accurate estimate of the possible power of the wind farm in order to be able to trade the reserve power. In this paper...

Characterization of a New Open Jet Wind Tunnel to Optimize and Test Vertical Axis Wind Turbines Using Flow Visualization and Measurement

DEFF Research Database (Denmark)

Tourn, S.; Gilabert, R.; Sánchez, V.

Characterize a new open jet wind tunnel and define the uniform test section where performance studies of small VAWTs will be carried out.......Characterize a new open jet wind tunnel and define the uniform test section where performance studies of small VAWTs will be carried out....

Wind direction dependent vertical wind shear and surface roughness parameter in two different coastal environments

International Nuclear Information System (INIS)

Bagavathsingh, A.; Srinivas, C.V.; Baskaran, R.; Venkatraman, B.; Sardar Maran, P.

2016-01-01

Atmospheric boundary layer parameters and surface layer parameterizations are important prerequisites for air pollution dispersion analysis. The turbulent flow characteristics vary at coastal and inland sites where the nuclear facilities are situated. Many pollution sources and their dispersion occur within the roughness sub layer in the lower atmosphere. In this study analysis of wind direction dependence vertical wind shear, surface roughness lengths and surface layer wind condition has been carried out at a coastal and the urban coastal site for the different wind flow regime. The differential response of the near coastal and inland urban site SBL parameters (wind shear, roughness length, etc) was examined as a function of wind direction

Trade unions and energy policy

International Nuclear Information System (INIS)

Evans, M.

1984-01-01

The subject is discussed under the headings: introduction (the review of energy policy by the Trades Union Congress); energy objectives and the energy crisis; energy planning (a planning framework for supply and demand; energy demand management; public planning inquiries; a plan for Britain; beyond Britain); a low energy growth strategy (UK primary energy demand); choice of supplies (coal; oil and gas; nuclear energy); new sources of energy (e.g.solar, geothermal, biofuels, wave, wind, tidal); conservation; health and safety - employers in the energy industries; conclusions. (U.K.)

Small Wind Turbine Technology Assessment

International Nuclear Information System (INIS)

Avia Aranda, F.; Cruz Cruz, I.

1999-01-01

The result of the study carried out under the scope of the ATYCA project Test Plant of Wind Systems for Isolated Applications, about the state of art of the small wind turbine technology (wind turbines with swept area smaller than 40 m 2 ) is presented. The study analyzes the collected information on 60 models of wind turbines from 23 manufacturers in the worldwide market. Data from Chinese manufacturers, that have a large participation in the total number of small wind turbines in operation, are not included, due to the unavailability of the technical information. (Author) 15 refs

Contextualizing Embodied Resources in Global Food Trade

Science.gov (United States)

MacDonald, G. K.; Brauman, K. A.; Sun, S.; West, P. C.; Carlson, K. M.; Cassidy, E. S.; Gerber, J. S.; Ray, D. K.

2014-12-01

Trade in agricultural commodities has created increasingly complex linkages between resource use and food supplies across national borders. Understanding the degree to which food production and consumption relies on trade is vital to understanding how to sustainably meet growing food demands across scales. We use detailed bilateral trade statistics and data on agricultural management to examine the land use and water consumption embodied in agricultural trade, which we relate to basic nutritional indicators to show how trade contributes to food availability worldwide. Agricultural trade carries enough calories to provide >1.7 billion people a basic diet each year. We identify key commodities and producer-consumer relationships that disproportionately contribute to embodied resource use and flows of food nutrition at the global scale. For example, just 15 disproportionately large soybean trades comprised ~10% the total harvested area embodied in export production. We conclude by framing these results in terms of the fraction of each country's food production and consumption that is linked to international trade. These findings help to characterize how countries allocate resources to domestic versus foreign food demand.

On the quality and value of probabilistic forecasts of wind generation

DEFF Research Database (Denmark)

Pinson, Pierre; Juban, Jeremie; Kariniotakis, Georges

2006-01-01

the uncertainty information, can be seen as optimal for the management or trading of wind generation. This paper explores the differences and relations between the quality (i.e. statistical performance) and the operational value of these forecasts. An application is presented on the use of probabilistic...... predictions for bidding in a European electricity market. The benefits of a probabilistic view of wind power forecasting are clearly demonstrated....

Characterization of a new open jet wind tunnel to optimize and test vertical axis wind turbines

DEFF Research Database (Denmark)

Tourn, Silvana; Pallarès, Jordi; Cuesta, Ildefonso

2017-01-01

Based on the increasing interest in urban environmental technologies, the study of small scale vertical axis wind turbines shows motivating challenges. In this paper, we present the characteristics and potentials of a new open jet wind tunnel. It has a nozzle exit area of 1.5 × 1.5 m2, and it can......%. The detailed characterization of the flow carried out indicates that the wind tunnel can be used to test small scale models of wind turbines....

Addressing Social and Institutional Barriers for Wind Energy Installations

Energy Technology Data Exchange (ETDEWEB)

Ramirez, L; Gonzalez, R; Varela, M [Ciemat. Madrid (Spain); Ramirez, I; Vicente, F [Consejeria de Medio Ambiente, Agricultura y Agua. Comunidad Autonoma de Murcia (Spain)

2000-07-01

This project has been jointly financed by the European Commission and developed within the Programme Thermie-B. The main tasks to carried out are: Revision of institutional and legal framework. The revision of institutional and legal framework of different participating countries, i. e. their comparison with the rest of the countries with a relevant role in the field of wind energy. Opinion poll carried out on the wind energy. By means of this means, one wants to test public opinion with respect to wind energy. So for such purpose, there are interviews carried out in the municipalities with wind parks, as well as in those where these are in the process of being installed or the project is in its due course. Simulation of wind parks installation. The Wind Park Wandered software tool is a Design and Visualisation tool developed by CINAR, which allows the preview of potential wind parks, evaluating their visual and audio impact. Production and distribution of information on wind energy. For such purpose, we can include the present publication with which one could summarise the main aspects associated with wind energy from its origin, the study of energy source (wind), and the machines that make use of it or the most relevant social and environmental contexts. Organizing informative seminars on the design possibilities of wind parks. At these seminar, one could assess the present wind energy situation in the European context and in each one of the participating countries. And possibilities of presenting WPW software as a design tool for wind parks. (Author) 12 refs.

Addressing Social and Institutional Barriers for Wind Energy Installations

International Nuclear Information System (INIS)

Ramirez, L.; Gonzalez, R.; Varela, M.; Saez, R.; Ramirez, I.; Vicente, F.

2000-01-01

This project has been jointly financed by the European Commission and developed within the Programme Thermie- B. The main tasks to carried out are: Revision of institutional and legal framework. The revision of institutional and legal framework of different participating countries, i.e. their comparison with the rest of the countries with a relevant role in the field of wind energy. Opinion poli carried out on the wind energy. By means of this means, one wants to test public opinion with respect to wind energy. So for such purpose, there are interviews carried out in the municipalities with wind parks, as well as in those where these are in the process of being installed or the project is in its due course. Simulation of wind parks installation. The Wind Park Wandered software tool is a Design and Visualisation tool developed by CINAR, which allows the preview of potential wind parks, evaluating their visual and audio impact. Production and distribution of information on wind energy. For such purpose, we can include the present publication with which one could summarise the main aspects associated with wind energy from its origin, the study of energy source (wind), and the machines that make use of it or the most relevant social and environmental contexts. Organising informative seminars on the design possibilities of wind parks. At these seminars, one could assess the present wind energy situation in the European context and in each one of the participating countries. And possibilities of presenting WPW software as a design tool for wind parks. (Author) 12 refs

Modeling and Finite Element Analysis of Load-Carrying Performance of a Wind Turbine Considering the Influence of Assembly Factors

Directory of Open Access Journals (Sweden)

Jianmei Wang

2017-03-01

Full Text Available In this work, a wind turbine shrink disk is used as the research object to investigate load-carrying performance of a multi-layer interference fit, and the theoretical model and finite element model are constructed. According to those models, a MW-level turbine shrink disk is designed, and a test device is developed to apply torque to this turbine shrink disk by hydraulic jack. Then, the circumferential slip between the contact surfaces is monitored and the slip of all contact surfaces is zero. This conclusion verifies the reasonability of the proposed models. The effect of the key influencing factors, such as machining deviation, assembly clearance and propel stroke, were analyzed. The contact pressure and load torque of the mating surfaces were obtained by building typical models with different parameters using finite element analysis (FEA. The results show that the minimum assembly clearance and the machining deviation within the machining range have little influence on load-carrying performance of multi-layer interference fit, while having a greater influence on the maximum assembly clearance and the propel stroke. The results also show that the load-carrying performance of a multiple-layer interference fit can be ensured only if the key factors are set within a reasonable design range. To avoid the abnormal operation of equipment caused by insufficient load torque, the propel stroke during practical assembly should be at least 0.95 times the designed propel stroke, which is significant in guiding the design and assembly of the multi-layer interference fit.

Performance of spanish wind turbines. Year 1995

International Nuclear Information System (INIS)

Lago, C.

1997-01-01

In this document we can find a statistical evaluation for the wind energy generation from each spanish wind farm referred to 1995 going on with the work that has been carried out since 1992, by initiative of the Wind Energy Division from Renewable Energy Institute. The purpose of this work is to contribute with interesting information for the wind environment and offer a global view from monthly performances of different wind farms. (Author)

Performance of spanish wind turbines. Year 1996

International Nuclear Information System (INIS)

Lago, C.

1998-01-01

In this document we can find a statistical evaluation for the wind energy generation from each spanish wind farm referred to 1996 going on with the work that has been carried out since 1992, by initiative of the Wind Energy Division from Renewable Energy Institute. The purpose of this work is to contribute with interesting information for the wind environment and offer a global view from monthly performances of different wind farms. (Author) 4 refs

Recurrence interval analysis of trading volumes.

Science.gov (United States)

Ren, Fei; Zhou, Wei-Xing

2010-06-01

We study the statistical properties of the recurrence intervals τ between successive trading volumes exceeding a certain threshold q. The recurrence interval analysis is carried out for the 20 liquid Chinese stocks covering a period from January 2000 to May 2009, and two Chinese indices from January 2003 to April 2009. Similar to the recurrence interval distribution of the price returns, the tail of the recurrence interval distribution of the trading volumes follows a power-law scaling, and the results are verified by the goodness-of-fit tests using the Kolmogorov-Smirnov (KS) statistic, the weighted KS statistic and the Cramér-von Mises criterion. The measurements of the conditional probability distribution and the detrended fluctuation function show that both short-term and long-term memory effects exist in the recurrence intervals between trading volumes. We further study the relationship between trading volumes and price returns based on the recurrence interval analysis method. It is found that large trading volumes are more likely to occur following large price returns, and the comovement between trading volumes and price returns is more pronounced for large trading volumes.

Priority Control Strategy of VSC-MTDC System for Integrating Wind Power

Directory of Open Access Journals (Sweden)

Wen-ning Yan

2015-01-01

Full Text Available For the obvious advantages in integrating wind power, multiterminal HVDC transmission system (VSC-MTDC is widely used. The priority control strategy is proposed in this paper considering the penetration rate of wind power for the AC grid. The strategy aims to solve the problems of power allocation and DC voltage control of the DC system. The main advantage of this strategy is that the demands for wind power of different areas can be satisfied and a power reference for the wind power trade can also be provided when wind farms transmit active power to several AC grids through the DC network. The objective is that power is well distributed according to the output power of wind farm with the demand of AC system and satisfactory control performance of DC voltage is obtained.

Estimation of the uncertainty in wind power forecasting

International Nuclear Information System (INIS)

Pinson, P.

2006-03-01

WIND POWER experiences a tremendous development of its installed capacities in Europe. Though, the intermittence of wind generation causes difficulties in the management of power systems. Also, in the context of the deregulation of electricity markets, wind energy is penalized by its intermittent nature. It is recognized today that the forecasting of wind power for horizons up to 2/3-day ahead eases the integration of wind generation. Wind power forecasts are traditionally provided in the form of point predictions, which correspond to the most-likely power production for a given horizon. That sole information is not sufficient for developing optimal management or trading strategies. Therefore, we investigate on possible ways for estimating the uncertainty of wind power forecasts. The characteristics of the prediction uncertainty are described by a thorough study of the performance of some of the state-of-the-art approaches, and by underlining the influence of some variables e.g. level of predicted power on distributions of prediction errors. Then, a generic method for the estimation of prediction intervals is introduced. This statistical method is non-parametric and utilizes fuzzy logic concepts for integrating expertise on the prediction uncertainty characteristics. By estimating several prediction intervals at once, one obtains predictive distributions of wind power output. The proposed method is evaluated in terms of its reliability, sharpness and resolution. In parallel, we explore the potential use of ensemble predictions for skill forecasting. Wind power ensemble forecasts are obtained either by converting meteorological ensembles (from ECMWF and NCEP) to power or by applying a poor man's temporal approach. A proposal for the definition of prediction risk indices is given, reflecting the disagreement between ensemble members over a set of successive look-ahead times. Such prediction risk indices may comprise a more comprehensive signal on the expected level

Combining the Power of Wind and Water in Quebec

Energy Technology Data Exchange (ETDEWEB)

Richard, D.

2007-07-01

Wind varies and is impossible to store, major factors that have curbed and continue to curb the development of wind power. Hydroelectric generating stations with reservoirs, on the other hand, are quite capable of adjusting their output and can thus buffer fluctuations in consumption or in the output of other generating facilities on the grid. Combining wind power and hydropower thus involves using hydroelectric generating stations to offset the intermittent nature of wind power. The consumer, however, does not automatically reap the benefits of this complementarity. To achieve this, Quebec has implemented a 1,000-MW balancing agreement between the hydropower producer and the electricity distributor, which has signed wind power purchase agreements. The balancing agreement establishes two charges: one based on firming capacity provided by the producer and another linked to errors in the forecast of wind power generation that the distributor makes each day. This structure compensates the producer for the reduced margin of flexibility it has to engage in energy trading. (auth)

Wind up with continuous intra-day electricity markets? The integration of large-share wind power generation in Denmark

International Nuclear Information System (INIS)

Karanfil, Fatih; Li, Yuanjing

2015-01-01

This paper suggests an innovative idea to examine the functionality of an electricity intra-day market by testing causality among its fundamental components. As fluctuations of poorly predicted wind power generation are challenging the stability of the current electricity system, an intra-day market design can play an important role in managing wind forecast errors. Using Danish and Nordic data, it investigates the main drivers of the price difference between the intra-day and day-ahead markets, and causality between wind forecast errors and their counterparts. Our results show that the wind and conventional generation forecast errors significantly cause the intra-day price to differ from the day-ahead price, and that the relative intra-day price decreases with the unexpected amount of wind generation. Cross-border electricity exchanges are found to be important to handle wind forecast errors. Additionally, some zonal differences with respect to both causality and impulse responses are detected. This paper provides the first evidence on the persuasive functioning of the intra-day market in the case of Denmark, whereby intermittent production deviations are effectively reduced, and wind forecast errors are jointly handled through the responses from demand, conventional generation, and intra-day international electricity trade. (authors)

Environmental impact of wind energy

DEFF Research Database (Denmark)

Mann, Jakob; Teilmann, Jonas

2013-01-01

One purpose of wind turbines is to provide pollution-free electric power at a reasonable price in an environmentally sound way. In this focus issue the latest research on the environmental impact of wind farms is presented. Offshore wind farms affect the marine fauna in both positive and negative...... ways. For example, some farms are safe havens for porpoises while other farms show fewer harbor porpoises even after ten years. Atmospheric computer experiments are carried out to investigate the possible impact and resource of future massive installations of wind turbines. The following questions...... are treated. What is the global capacity for energy production by the wind? Will the added turbulence and reduced wind speeds generated by massive wind farms cool or heat the surface? Can wind farms affect precipitation? It is also shown through life-cycle analysis how wind energy can reduce the atmospheric...

Permit trading and credit trading

DEFF Research Database (Denmark)

Boom, Jan-Tjeerd; R. Dijstra, Bouwe

This paper compares emissions trading based on a cap on total emissions (permit trading) and on relative standards per unit of output (credit trading). Two types of market structure are considered: perfect competition and Cournot oligopoly. We find that output, abatement costs and the number...... of firms are higher under credit trading. Allowing trade between permit-trading and credit-trading sectors may increase in welfare. With perfect competition, permit trading always leads to higher welfare than credit trading. With imperfect competition, credit trading may outperform permit trading....... Environmental policy can lead to exit, but also to entry of firms. Entry and exit have a profound impact on the performance of the schemes, especially under imperfect competition. We find that it may be impossible to implement certain levels of total industry emissions. Under credit trading several levels...

POTENTIAL TRADE EFFECTS OF TARIFF LIBERALIZATION UNDER THE TRANSATLANTIC TRADE AND INVESTMENT PARTNERSHIP (TTIP FOR THE EU AGRI-FOOD SECTOR

Directory of Open Access Journals (Sweden)

Agnieszka Poczta-Wajda

2017-06-01

Full Text Available  The aim of this article is to determine the potential trade effects of Transatlantic Trade and Investment Partnership (TTIP for the EU agri-food sector. The ex post analysis covered the characteristics of agri-food trade between the EU and the US in the years 2004–2014 on the basis of statistical data from the database of the World Bank WITS. The ex ante evaluation was carried out using SMART – a partial equilibrium model. The results of the study indicate that although bilateral agri-food trade relations of the EU–US have relatively little importance, but it is significant at the individual industries level. TTIP agreement, which includes the reduction of tariff barriers to agri-food trade between the EU and the US, will contribute to boosting bilateral agri-food trade to a greater extent for the US. The creation of a free trade produces mostly creation effect, whereby it will be asymmetric – concentrated in a few product groups.

Wind turbine with lightning protection system

DEFF Research Database (Denmark)

2016-01-01

The present invention relates to a wind turbine comprising a lightning protection system comprising a waveguide interconnecting a communication device and a signal-carrying structure. In other aspects, the present invention relates to the use of a waveguide in a lightning protection system...... of a wind turbine, a power splitter and its use in a lightning protection system of a wind turbine....

Energy from biomass. Summaries of the Biomass Projects carried out as part of the Department of Trade and Industry's New and Renewable Energy Programme. Vol. 3: converting wood fuel to energy

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-12-01

These volumes of summaries provide easy access to the many projects carried out in the Energy from Biomass programme area as part of the Department of Trade and Industry's New and Renewable Energy Programme. The summaries in this volume cover contractor reports on the subject published up to December 1997. (author)

Supply Chain and Blade Manufacturing Considerations in the Global Wind Industry (Presentation)

Energy Technology Data Exchange (ETDEWEB)

James, Ted [National Renewable Energy Lab. (NREL), Golden, CO (United States); Goodrich, Alan [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2013-12-12

This briefing provides an overview of supply chain developments in the global wind industry and a detailed assessment of blade manufacturing considerations for U.S. end-markets. The report discusses the international trade flows of wind power equipment, blade manufacturing and logistical costs, and qualitative issues that often influence factory location decisions. To help guide policy and research and development strategy decisions, this report offers a comprehensive perspective of both quantitative and qualitative factors that affect selected supply chain developments in the growing wind power industry.

On wind power in the Nordic countries

International Nuclear Information System (INIS)

Nilsson, Lars J.

1993-01-01

The purpose of this article is to discuss the prospects for a large scale introduction of wind power in the Nordic countries especially with respect to the consequences for small independent power producers of the ongoing and planned deregulation of the electricity sector. The recoverable wind resources are great and integration costs are small due to the good load following capability of the existing Swedish and Norwegian hydroelectric capacity. The structure of the present electricity system and the current principles for electricity trade are reviewed. To what extent wind power will be the technology of choice for capacity replacement and expansion depends on how intermittent power will be valued on the future electricity market. In a deregulated market, wind power may be priced below its value unless appropriate pricing mechanisms are developed. Market reforms should therefore include consideration of the large contribution that wind energy must make in a future electricity system which, in addition to being economically efficient, is compatible with broader societal goals. 47 refs, 2 figs

Wind tower service lift

Science.gov (United States)

Oliphant, David; Quilter, Jared; Andersen, Todd; Conroy, Thomas

2011-09-13

An apparatus used for maintaining a wind tower structure wherein the wind tower structure may have a plurality of legs and may be configured to support a wind turbine above the ground in a better position to interface with winds. The lift structure may be configured for carrying objects and have a guide system and drive system for mechanically communicating with a primary cable, rail or other first elongate member attached to the wind tower structure. The drive system and guide system may transmit forces that move the lift relative to the cable and thereby relative to the wind tower structure. A control interface may be included for controlling the amount and direction of the power into the guide system and drive system thereby causing the guide system and drive system to move the lift relative to said first elongate member such that said lift moves relative to said wind tower structure.

Optimization of airborne wind energy generators

NARCIS (Netherlands)

Fagiano, L.; Milanese, M.; Piga, D.

2012-01-01

This paper presents novel results related to an innovative airborne wind energy technology, named Kitenergy, for the conversion of high-altitude wind energy into electricity. The research activities carried out in the last five years, including theoretical analyses, numerical simulations, and

Articles from Volume 2, Issue 1, 2006, Journal of International Agricultural Trade and Development

OpenAIRE

Anonymous

2006-01-01

Content: Abler, David. "Introduction: Modeling Global Food and Agricultural Markets." (pp. v); (1) Sheldon, Ian. "Monopolistic Competition and Trade: Does the Theory Carry any Empirical Weight?" (pp. 1-32); (2) Abbott, Phillip. "Comment on: Monopolistic Competition and Trade: Does the Theory Carry any Empirical Weight?" (pp. 33-38); (3) Sarker, Rakhal and Yves Surry. "Product Differentiation and Trade in Agri-Food Products: Taking Stock and Looking Forward." (pp. 39-78); (4) Alston, Julian M....

NOx trade. Case studies

International Nuclear Information System (INIS)

Jantzen, J.

2002-01-01

Some of the questions with respect to the trade of nitrogen oxides that businesses in the Netherlands have to deal with are dealt with: should a business buy or sell rights for NOx emission; which measures must be taken to reduce NOx emission; how much must be invested; and how to deal with uncertainties with regard to prices. Simulations were carried out with the MOSES model to find the answers to those questions. Results of some case studies are presented, focusing on the chemical sector in the Netherlands. Finally, the financial (dis)advantages of NOx trade and the related uncertainties for a single enterprise are discussed [nl

Sizing wind/photovoltaic hybrids for households in inner Mongolia

Energy Technology Data Exchange (ETDEWEB)

Barley, C.D.; Lew, D.J.; Flowers, L.T. [National Renewable Energy Lab., Golden, CO (United States)

1997-12-31

Approximately 140,000 wind turbines currently provide electricity to about one-third of the non-grid-connected households in Inner Mongolia. However, these households often suffer from a lack of power during the low-wind summer months. This report describes an analysis of hybrid wind/photovoltaic (PV) systems for such households. The sizing of the major components is based on a subjective trade-off between the cost of the system and the percent unmet load, as determined by the Hybrid2 software in conjunction with a simplified time-series model. Actual resource data (wind speed and solar radiation) from the region are processed so as to best represent the scenarios of interest. Small wind turbines of both Chinese and U.S. manufacture are considered in the designs. The results indicate that combinations of wind and PV are more cost-effective than either one alone, and that the relative amount of PV in the design increases as the acceptable unmet load decreases and as the average wind speed decreases.

16 CFR 1.8 - Nature, authority and use of trade regulation rules.

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Nature, authority and use of trade regulation rules. 1.8 Section 1.8 Commercial Practices FEDERAL TRADE COMMISSION ORGANIZATION, PROCEDURES AND... Nature, authority and use of trade regulation rules. (a) For the purpose of carrying out the provisions...

Study on the influence of attitude angle on lidar wind measurement results

Science.gov (United States)

Han, Xiaochen; Dou, Peilin; Xue, Yangyang

2017-11-01

When carrying on wind profile measurement of offshore wind farm by shipborne Doppler lidar technique, the ship platform often produces motion response under the action of ocean environment load. In order to measure the performance of shipborne lidar, this paper takes two lidar wind measurement results as the research object, simulating the attitude of the ship in the ocean through the three degree of freedom platform, carrying on the synchronous observation test of the wind profile, giving an example of comparing the wind measurement data of two lidars, and carrying out the linear regression statistical analysis for all the experimental correlation data. The results show that the attitude angle will affect the precision of the lidar, The influence of attitude angle on the accuracy of lidar is uncertain. It is of great significance to the application of shipborne Doppler lidar wind measurement technology in the application of wind resources assessment in offshore wind power projects.

Computational Modelling of Materials for Wind Turbine Blades: Selected DTU Wind Energy Activities.

Science.gov (United States)

Mikkelsen, Lars Pilgaard; Mishnaevsky, Leon

2017-11-08

Computational and analytical studies of degradation of wind turbine blade materials at the macro-, micro-, and nanoscale carried out by the modelling team of the Section Composites and Materials Mechanics, Department of Wind Energy, DTU, are reviewed. Examples of the analysis of the microstructural effects on the strength and fatigue life of composites are shown. Computational studies of degradation mechanisms of wind blade composites under tensile and compressive loading are presented. The effect of hybrid and nanoengineered structures on the performance of the composite was studied in computational experiments as well.

Wind Forces on Container Ships

DEFF Research Database (Denmark)

Andersen, Ingrid Marie Vincent

2012-01-01

An investigation of the wind forces acting on a 9,000+ TEU container ship has been carried out through a series of wind tunnel tests. It was investigated how the wind forces depend on the container configuration on the deck using a 1:450 scale model and a series of appropriate container...... are presented as nondimensional coefficients. It is concluded, that the measured forces and moment depend on the container configuration on deck, and the results may provide a general idea of how the magnitude of the wind forces is affected by a given container stacking configuration on a similar container ship....

Integrating Structural Health Management with Contingency Control for Wind Turbines

Directory of Open Access Journals (Sweden)

Kai Goebel

2013-01-01

Full Text Available Maximizing turbine up-time and reducing maintenance costs are key technology drivers for wind turbine operators. Components within wind turbines are subject to considerable stresses due to unpredictable environmental conditions resulting from rapidly changing local dynamics. In that context, systems health management has the aim to assess the state-of-health of components within a wind turbine, to estimate remaining life, and to aid in autonomous decision-making to minimize damage to the turbine. Advanced contingency control is one way to enable autonomous decision-making by providing the mechanism to enable safe and efficient turbine operation. The work reported herein explores the integration of condition monitoring of wind turbine blades with contingency control to balance the trade-offs between maintaining system health and energy capture. Results are demonstrated using a high fidelity simulator of a utility-scale wind turbine.

Cost optimization of wind turbines for large-scale offshore wind farms

International Nuclear Information System (INIS)

Fuglsang, P.; Thomsen, K.

1998-02-01

This report contains a preliminary investigation of site specific design of off-shore wind turbines for a large off-shore wind farm project at Roedsand that is currently being proposed by ELKRAFT/SEAS. The results were found using a design tool for wind turbines that involve numerical optimization and aeroelastic calculations of response. The wind climate was modeled in detail and a cost function was used to estimate costs from manufacture and installation. Cost of energy is higher for off-shore installations. A comparison of an off-shore wind farm site with a typical stand alone on-shore site showed an increase of the annual production of 28% due to the difference in wind climate. Extreme loads and blade fatigue loads were nearly identical, however,fatigue loads on other main components increased significantly. Optimizations were carried out to find the optimum overall off-shore wind turbine design. A wind turbine for the off-shore wind farm should be different compared with a stand-alone on-shore wind turbine. The overall design changed were increased swept area and rated power combined with reduced rotor speed and tower height. Cost was reduced by 12% for the final 5D/14D off-shore wind turbine from 0.306 DKr/kWh to 0.270 DKr/kWh. These figures include capital costs from manufacture and installation but not on-going costs from maintenance. These results make off-shore wind farms more competitive and comparable to the reference on-shore stand-alone wind turbine. A corresponding reduction of cost of energy could not be found for the stand alone on-shore wind turbine. Furthermore the fatigue loads on wind turbines in on-shore wind farms will increase and cost of energy will increase in favor of off-shore wind farms. (au) EFP-95; EU-JOULE-3; 21 tabs., 7 ills., 8 refs

Results of verification and investigation of wind velocity field forecast. Verification of wind velocity field forecast model

International Nuclear Information System (INIS)

Ogawa, Takeshi; Kayano, Mitsunaga; Kikuchi, Hideo; Abe, Takeo; Saga, Kyoji

1995-01-01

In Environmental Radioactivity Research Institute, the verification and investigation of the wind velocity field forecast model 'EXPRESS-1' have been carried out since 1991. In fiscal year 1994, as the general analysis, the validity of weather observation data, the local features of wind field, and the validity of the positions of monitoring stations were investigated. The EXPRESS which adopted 500 m mesh so far was improved to 250 m mesh, and the heightening of forecast accuracy was examined, and the comparison with another wind velocity field forecast model 'SPEEDI' was carried out. As the results, there are the places where the correlation with other points of measurement is high and low, and it was found that for the forecast of wind velocity field, by excluding the data of the points with low correlation or installing simplified observation stations to take their data in, the forecast accuracy is improved. The outline of the investigation, the general analysis of weather observation data and the improvements of wind velocity field forecast model and forecast accuracy are reported. (K.I.)

75 FR 2159 - In the Matter of Certain Variable Speed Wind Turbines and Components Thereof; Termination of...

Science.gov (United States)

2010-01-14

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-641] In the Matter of Certain Variable Speed Wind Turbines and Components Thereof; Termination of Investigation With Final Determination of No..., and the sale within the United States after importation of certain variable speed wind turbines and...

NTF – wind speed comparison

DEFF Research Database (Denmark)

Vesth, Allan; Gómez Arranz, Paula

The report describes measurements carried out on a given turbine. A comparison between wind speed on the met mast and Nacelle Wind speed are made and the results are presented on graphs and in a table. The data used for the comparison are the data that are same as used for the power curve report...

The Phasing of the Process of Diagnosing the Personnel Potential at Trade Enterprise

Directory of Open Access Journals (Sweden)

Peniuk Valeriia O.

2017-03-01

Full Text Available The article is aimed at carrying out phasing of the process of diagnosing the personnel potential at trade enterprise, taking into consideration the possible restrictions of a structural nature. The article determines the main causes for unequal attitude by the directors of differently sized trade enterprises of Ukraine towards diagnosing the personnel potential and personnel evaluation. The author’s vision of the phasing of the process of diagnosing the personnel potential has been submitted. An economic-mathematical model of the optimal implementation of the stages of diagnostics of the personnel potential at trade enterprise has been built. A list of principles has been compiled, along with clarifying their contents, on the basis of which diagnosing the personnel potential at trade enterprise should be carried out. The author’s definition of the concept of «desired status of the personnel potential» for trade enterprise has been formulated. Examples of endogenous and exogenous factors that impact the desired status of the personnel potential of trading enterprise and cause its changing have been provided. Prospects for further research in this direction can be research on the diagnostics of other constituents of the strategic potential of trade enterprise, as well as improvement or development of a new methodological instrumentarium to carry out diagnostics of the personnel potential at enterprises.

Windonomics. Empirical essays on the economics of wind power in the Nordic electricity market

Energy Technology Data Exchange (ETDEWEB)

Mauritzen, Johannes

2012-07-01

From the introduction: The following chapters in this dissertation take up three topics surrounding the interaction of wind power investment in Denmark and the functioning of the deregulated Nordic electricity market. The first two chapters take up the issue of how wind power a affects prices in the deregulated market. I find that electricity price variation in the spot market is lower in days with more wind power. In the following chapter I extend this analysis to see how wind power in Denmark affects prices in neighbouring hydro power dominated Norway. I find that wind power affects the magnitude of trade between the countries asymmetrically - dependent on the net direction of trade. I also find that wind power has a slight but statistically significant negative effect on prices in Norway, likely due to a slackening of hydro power producers supply constraints. The last chapter starts with the observation that most turbines are scrapped in order to make room for a newer turbine. An opportunity cost that comes from the interaction of scarce land resources, technological change and government policy is then a dominant reason for the scrapping of wind turbines. This leads to the implication that turbines located on windier, better situated land have a higher risk of being scrapped. Policy is also shown to have a strong and in some respects unexpected effect on scrappings. Over the last two decades two major trends have taken place in power markets around the world. The first has been a movement towards market based power systems. Vertically integrated power companies have been split into component generation, transmission and retailing companies. Generation and retailing have been opened to competition. Increasingly, regulated prices and bilateral trade are being replaced by regulated markets that establish prices through auction mechanisms. The second trend has been investment in renewable and intermittent energy sources - notably wind power. What started as

The Geometric Phase of Stock Trading.

Science.gov (United States)

Altafini, Claudio

2016-01-01

Geometric phases describe how in a continuous-time dynamical system the displacement of a variable (called phase variable) can be related to other variables (shape variables) undergoing a cyclic motion, according to an area rule. The aim of this paper is to show that geometric phases can exist also for discrete-time systems, and even when the cycles in shape space have zero area. A context in which this principle can be applied is stock trading. A zero-area cycle in shape space represents the type of trading operations normally carried out by high-frequency traders (entering and exiting a position on a fast time-scale), while the phase variable represents the cash balance of a trader. Under the assumption that trading impacts stock prices, even zero-area cyclic trading operations can induce geometric phases, i.e., profits or losses, without affecting the stock quote.

Performance trade-offs and ageing in the 'world's greatest athletes'.

Science.gov (United States)

Careau, Vincent; Wilson, Robbie S

2017-08-16

The mechanistic foundations of performance trade-offs are clear: because body size and shape constrains movement, and muscles vary in strength and fibre type, certain physical traits should act in opposition with others (e.g. sprint versus endurance). Yet performance trade-offs are rarely detected, and traits are often positively correlated. A potential resolution to this conundrum is that within -individual performance trade-offs can be masked by among -individual variation in 'quality'. Although there is a current debate on how to unambiguously define and account for quality, no previous studies have partitioned trait correlations at the within- and among-individual levels. Here, we evaluate performance trade-offs among and within 1369 elite athletes that performed in a total of 6418 combined-events competitions (decathlon and heptathlon). Controlling for age, experience and wind conditions, we detected strong trade-offs between groups of functionally similar events (throwing versus jumping versus running) occurring at the among-individual level. We further modelled individual (co)variation in age-related plasticity of performance and found previously unseen trade-offs in throwing versus running performance that manifest through ageing. Our results verify that human performance is limited by fundamental genetic, environmental and ageing constraints that preclude the simultaneous improvement of performance in multiple dimensions. Identifying these constraints is fundamental to understanding performance trade-offs and predicting the ageing of motor function. © 2017 The Author(s).

Wind Profiling Radar

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Clutter present in radar return signals as used for wind profiling is substantially removed by carrying out a Daubechies wavelet transformation on a time series of...

Noise from wind turbines

International Nuclear Information System (INIS)

Andersen, B.; Jakobsen, J.

1992-11-01

Based on a previous project concerning the calculation of the amount of noise emanating from wind turbine arrays, this one examines the subject further by investigating whether there could be significant differences in the amount of noise made by individual wind turbines in an array, and whether the noise is transmitted in varying directions - so that when it is carried in the same direction as the wind blows it would appear to be louder. The aim was also to determine whether the previously used method of calculation lacked precision. It was found that differences in noise niveaux related to individual wind turbines were insignificant and that noise was not so loud when it was not borne in the direction of the wind. It was necessary to change the method of calculation as reckoning should include the influence of the terrain, wind velocity and distance. The measuring and calculation methods are exemplified and the resulting measurements are presented in detail. (AB)

Programs of financing of foreign trade ebrr and their implementation in Ukraine

OpenAIRE

Kovtonyuk, O.

2009-01-01

In the article justified the importance of IMF and Worldbank Group in the financing of international trade, and carried out the analysis of international trade projects financing, which have been implemented in Ukraine.

An Experiment on Wind Energy

Science.gov (United States)

Lombardo, Vincenzo; Fiordilino, Emilio; Gallitto, Aurelio Agliolo; Aglieco, Pasquale

2012-01-01

We discuss an experiment on wind energy performed with home-made apparatus. The experiment reproduces a laboratory windmill, which can pump water from a lower level to a higher one. By measuring the gain of the gravitational potential energy of the pumped water, one can determine the power extracted from the wind. The activity was carried out with…

Review report 2004. The Danish offshore wind farm demonstration project: Horns Rev and Nysted offshore wind farms. Environmental impact assessment and monitoring

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-10-15

The present review report presents the two wind farms Horns Rev and Nysted with regard to environmental characteristics and the results of the environmental studies carried out in connection with the Environmental Impact Assessment (EIA) and the baseline and monitoring programmes at the two sites. The descriptions of the programmes are based on extracts from the individual annual reports. Detailed information on method, programmes and conclusions can be found in these reports (see Appendix 1). This review report is divided into two parts. The first part contains a description of the potential environmental impacts of offshore wind farms and the potentially affected part of the environment. The second part includes a description of Horns Rev and Nysted Offshore Wind Farm and the environmental studies carried out here until the end of 2003. Appendix I is a list of the literature published on the studies carried out at Horns Rev and Nysted Offshore Wind Farm. Appendix II is a list of some of the literature relevant to the demonstration projects but not directly related to the projects. The offshore wind farm situated in the Roedsand area is officially denoted Nysted Offshore Wind Farm, and in the present report the denotation 'Nysted' will be used as well when referring to Nysted Offshore Wind Farm. The denotation Roedsand will be used when referring to the actual area Roedsand. (au)

Review report 2003. The Danish offshore wind farm demonstration project: Horns Rev and Nysted offshore wind farms. Environmental impact assessment and monitoring

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-09-15

The present review report presents the two wind farms Homs Rev and Nysted, with regard to environmental characteristics and the results of the environmental studies carried out in connection with the Environmental Impact Assessment (EIA) and the baseline and monitoring programmes at the two sites. The descriptions of the programmes are based on extracts from the individual annual reports. Detailed information on methods, programmes and conclusions can be found in these reports. This review report is divided into two parts. The first part contains a description of the potential environmentally impacts of offshore wind farms and the potentially affected part of the environment. The second part includes a description of Horns Rev and Nysted Offshore Wind Farm and the environmental studies carried out here until the end of 2003. Appendix I is a list of the literature published on the studies carried out at Hors Rev and Nysted Offshore Wind Farm. Appendix II is a list of some of the literature relevant to the demonstration projects but not directly related to the projects. The offshore wind farm situated at the bdsand area is officially denoted Nysted Offshore Wind Farm, and in the present report the denotation 'Nysted' will be used as well when referring to Nysted Offshore Wind Farm. The denotation Roedsand will be used when referring to the actual area Roedsand. (au)

Review report 2004. The Danish offshore wind farm demonstration project: Horns Rev and Nysted offshore wind farms. Environmental impact assessment and monitoring

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-10-15

The present review report presents the two wind farms Horns Rev and Nysted with regard to environmental characteristics and the results of the environmental studies carried out in connection with the Environmental Impact Assessment (EIA) and the baseline and monitoring programmes at the two sites. The descriptions of the programmes are based on extracts from the individual annual reports. Detailed information on method, programmes and conclusions can be found in these reports (see Appendix 1). This review report is divided into two parts. The first part contains a description of the potential environmental impacts of offshore wind farms and the potentially affected part of the environment. The second part includes a description of Horns Rev and Nysted Offshore Wind Farm and the environmental studies carried out here until the end of 2003. Appendix I is a list of the literature published on the studies carried out at Horns Rev and Nysted Offshore Wind Farm. Appendix II is a list of some of the literature relevant to the demonstration projects but not directly related to the projects. The offshore wind farm situated in the Roedsand area is officially denoted Nysted Offshore Wind Farm, and in the present report the denotation 'Nysted' will be used as well when referring to Nysted Offshore Wind Farm. The denotation Roedsand will be used when referring to the actual area Roedsand. (au)

The impact of Chinese carbon emission trading scheme (ETS) on low carbon energy (LCE) investment

International Nuclear Information System (INIS)

Mo, Jian-Lei; Agnolucci, Paolo; Jiang, Mao-Rong; Fan, Ying

2016-01-01

China is planning to introduce emission trading scheme (ETS) to decrease CO_2 emission. As low carbon energy (LCE) will play a pivotal role in reducing CO_2 emissions, our paper is to assess the extent and the conditions under which a carbon ETS can deliver LCE investment in China. We chose wind technology as a case study and a real-option based model was built to explore the impact of a number of variables and design features on investment decisions, e.g. carbon and electricity price, carbon market risk, carbon price floor and ceiling and on-grid ratio. We compute critical values of these variables and features and explore trade-offs among them. According to our work, a carbon ETS has a significant effect on wind power plant investment although it cannot support investment in wind power on its own. Carbon price stabilization mechanisms such as carbon price floor can significantly improve the effect of carbon ETS but the critical floor to support investment is still much higher than the carbon price in China pilot ETSs. Our results show that other policy measures will be needed to promote low-carbon energy development in China. - Highlights: • The impact of Chinese emission trading scheme on low carbon energy investment is assessed. • A real-option based investment decision model under uncertainty is built and employed. • Key variables and features of ETS influencing wind power investment are explored. • Chinese carbon ETS cannot support low carbon energy investment on its own. • Other policy measures complementing ETS are still needed and should be coordinated.

Optimum sizing of wind-battery systems incorporating resource uncertainty

International Nuclear Information System (INIS)

Roy, Anindita; Kedare, Shireesh B.; Bandyopadhyay, Santanu

2010-01-01

The inherent uncertainty of the wind is a major impediment for successful implementation of wind based power generation technology. A methodology has been proposed in this paper to incorporate wind speed uncertainty in sizing wind-battery system for isolated applications. The uncertainty associated with the wind speed is incorporated using chance constraint programming approach. For a pre-specified reliability requirement, a deterministic equivalent energy balance equation may be derived from the chance constraint that allows time series simulation of the entire system. This results in a generation of the entire set of feasible design options, satisfying different system level constraints, on a battery capacity vs. generator rating diagram, also known as the design space. The proposed methodology highlights the trade-offs between the wind turbine rating, rotor diameter and the battery size for a given reliability of power supply. The optimum configuration is chosen on the basis of the minimum cost of energy (US$/kWh). It is shown with the help of illustrative examples that the proposed methodology is generic and flexible to incorporate alternate sub-component models. (author)

Centennial changes in North Pacific anoxia linked to tropical trade winds

Science.gov (United States)

Deutsch, Curtis; Berelson, William; Thunell, Robert; Weber, Thomas; Tems, Caitlin; McManus, James; Crusius, John; Ito, Taka; Baumgartner, Timothy; Ferreira, Vicente; Mey, Jacob; van Geen, Alexander

2014-01-01

Climate warming is expected to reduce oxygen (O2) supply to the ocean and expand its oxygen minimum zones (OMZs). We reconstructed variations in the extent of North Pacific anoxia since 1850 using a geochemical proxy for denitrification (δ15N) from multiple sediment cores. Increasing δ15N since ~1990 records an expansion of anoxia, consistent with observed O2 trends. However, this was preceded by a longer declining δ15N trend that implies that the anoxic zone was shrinking for most of the 20th century. Both periods can be explained by changes in winds over the tropical Pacific that drive upwelling, biological productivity, and O2 demand within the OMZ. If equatorial Pacific winds resume their predicted weakening trend, the ocean’s largest anoxic zone will contract despite a global O2 decline.

Offshore and onshore wind turbine wake meandering studied in an ABL wind tunnel

DEFF Research Database (Denmark)

Barlas, Emre; Buckingham, Sophia; Glabeke, Gertjan

2015-01-01

Scaled wind turbine models have been installed in the VKI L1-B atmospheric boundary layer wind tunnel at offshore and onshore conditions. Time-resolved measurements were carried out with three component hot wire anemometry and stereo-PIV in the middle vertical plane of the wake up to eleven turbine...... diameter downstream. The results show an earlier wake recovery for the onshore case. The effect of inflow conditions and the wind turbine’s working conditions on wake meandering was investigated. Wake meandering was detected by hot wire anemometry through a low frequency peak in the turbulent power...

Pre-feasibility study of 80mw onshore wind farm

International Nuclear Information System (INIS)

Almas, M.S.

2014-01-01

This paper discusses a pre-feasibility study of 80MW onshore wind farm in the KPK (Khyber Pakhtunkhwa) province previously known as NWFP (North West Frontier) Province of Pakistan. The realistic data of wind speed is collected from Laboratory of Meteorology and Climatology (University of the Punjab) to study the feasibility of wind farm. Detailed analysis of wind turbines from four different manufacturers is carried out together with justifications of selecting a particular wind turbine. Issues related to site selection, wind farm civil foundation, recommendations for a particular choice of tower along with environmental effects are presented. Wind data analysis is carried out by using WINDROSE PRO software to determine the resultant direction of wind at the selected site for wind farm layout. The wind distribution at hub height of the wind turbine is calculated and is used to compute annual power production by the wind farm using power curves of the wind turbine. Electrical network integration issues of wind farm to the external grid are studied and the optimum point of connection is proposed. Finally, economic analysis of the whole wind farm project depending upon the LCC (Life Cycle Cost Analysis) is presented and the feasibility of the project from the investor's point of view is identified. The study concludes that the cost per kilowatt hour of electricity generated by this wind power plant will be 10.4 PKR/kWh and the payback period for the whole project is about 11.2 years. (author)

Design and operation of power systems with large amounts of wind power. Final summary report, IEA WIND Task 25, Phase two 2009 - 2011

Energy Technology Data Exchange (ETDEWEB)

Holttinen, H.; Kiviluoma, J. [VTT Technical Research Centre of Finland, Espoo (Finland); Robitaille, A. [Hydro Quebec, Montreal QC (Canada)] [and others

2013-01-15

This report provides a summary of the results from recent wind integration studies. The studies address concerns about the impact of wind power's variability and uncertainty on power system reliability and costs as well as grid reinforcement needs. Quantifiable results are presented as summary graphs: results as a MW-increase in reserve requirements, or euro/MWh increase in balancing costs, or results for capacity value of wind power. Other results are briefly summarised, together with existing experience on the issues. There is already significant experience in integrating wind power in power systems. The mitigation of wind power impacts include more flexible operational methods, incentivising flexibility in other generating plants, increasing interconnection to neighbouring regions, and application of demand-side flexibility. Electricity storage is still not as cost effective in larger power systems as other means of flexibility, but is already seeing initial applications in places with limited transmission. Electricity markets, with cross-border trade of intra-day and balancing resources and emerging ancillary services markets, are seen as promising for future large penetration levels for wind power. (orig.)

Incentives and barriers for wind power expansion and system integration in Denmark

DEFF Research Database (Denmark)

Hvelplund, Frede; Ostergaard, Poul Alberg; Meyer, Niels I

2017-01-01

In Denmark expansion of on-shore, near-shore and off-shore wind power is planned to increase the wind power share to 50% of electricity consumption by 2020. In this situation a continuation of past policies will not suffice, and a dual-track incentive system that both establishes incentives...... for investing in wind power and integration infrastructure with integration between the electricity, heating and transportation sectors, is required. The current Danish taxation system discourages electricity use and works against this integration. Likewise, the current day-ahead electricity spot market...... is not appropriate for a high-wind future as wind reduces price levels, but integration across sectors can partly assist in increasing demand and prices. The European Emission Trading System does not suffice in providing a level playing field for wind power and thus needs a revision. Another barrier for on...

Distribution and provenance of wind-blown SE Pacific surface sediments

NARCIS (Netherlands)

Saukel, C.; Lamy, F.; Stuut, J.B.W.; Tiedemann, R.; Vogt, C.

2011-01-01

The reconstruction of low-latitude ocean-atmosphere interactions is one of the major issues of (paleo-) environmental studies. The trade winds, extending over 20 degrees to 30 degrees of latitude in both hemispheres, between the subtropical highs and the intertropical convergence zone, are major

Proceedings of CanWEA's 2006 small wind conference

International Nuclear Information System (INIS)

2006-01-01

Small wind energy systems are typically comprised of a single wind turbine for on-site power generation of between 300 watts to 100 kW. They are suited for use in remote locations, as well as on farms or for on-grid residential applications. Small wind customers are concerned about environmental issues as well as the reliability of the electric power grid. Recent increases in electricity prices have contributed to a renewed interest in small wind systems. Primary distributed wind market growth areas include residential grid-connected sites; schools, public facilities and farmer co-operatives; and farms, business and industry. Growth in small wind applications has not been matched by an increase in government incentives, and the lack of clear technical standards for wind systems may negatively impact public perceptions of the industry. This conference provided an overview of the small wind industry in Canada. The conference provided a forum for wind industry members, government agencies, and academics to explore challenges and barriers to the growth of the small wind industry. The conference, which was held as part of the larger annual CanWEA 2006 conference and trade show, was divided into 3 sessions: (1) policies to support small wind; (2) doing business with small wind; and (3) small wind technical insights. Recommendations for the certification of small wind turbines were provided, as well as a model zoning by-law. Technical issues included the development of high penetration wind/diesel systems for isolated communities in the Arctic; technical challenges with small turbines; and siting guidelines for consumers. Several small wind turbine owners reviewed some of the challenges of both buying and using wind systems. Technical and market barriers for distributed wind applications were also discussed. The conference featured 13 presentations, of which 12 were catalogued separately for inclusion in this database. refs., tabs., figs

Wind Conditions for Wind Farm Hanstholm

DEFF Research Database (Denmark)

Pena Diaz, Alfredo; Hahmann, Andrea N.; Mann, Jakob

The net annual energy production (AEP) of the Hanstholm Wind Farm is 158 GWh per year for the Siemens SWT-3.6-120 turbine and 140 GWh for the Vestas V112-3.0 turbine. These values have an uncertainty (standard deviation) of 6%. This result is mainly based on the data for Risø DTU’s test station...... at Høvsøre where wind speeds are measured at approximately the same height as the turbines at Hanstholm and where the terrain is similar. On top of that meso-scale modeling has been used to extrapolate the climatology from Høvsøre to Hanstholm increasing the AEP by almost 6% compared to just using...... the Høvsøre climatology directly. This method of extrapolation is rather new, but several older investigations indicate that the wind resource at Hanstholm is slightly higher than at Høvsøre. The work is carried out for Grontmij-Carl Bro according to a contract dated January 18th 2011....

77 FR 71780 - U.S. Trade Mission to Asia in Conjunction With Trade Winds-Asia, The Philippines, Hong Kong...

Science.gov (United States)

2012-12-04

..., environmental technologies and services, financial services, franchising, healthcare & medical, hotel/restaurant... selection criteria as outlined below. A minimum of 65 companies and/or trade associations will be selected.... content. Selection Criteria for Participation Selection will be based on the following criteria...

Repowering of wind farms - A case study

Energy Technology Data Exchange (ETDEWEB)

Nivedh, B.S. [Quality Engineering and Software Technologies, Bangalore (India); Devi, R.P.K. [College of Engineering. Power Systems Engineering, Guindy (India); Sreevalsan, E. [Gamesa Wind Turbines India Private Limited, Chennai (India)

2012-07-01

The main objective of the study is to devise a method for assessing the repowering potential and to improve the energy output from the wind farms and also to understand the impact on the power quality due to repowering. With repowering, the first-generation wind turbines can be replaced with modern multi-megawatt wind turbines. To carry-out the study an old wind farm located at Kayathar, Tamilnadu is selected. The wind farm was commissioned in 1990's with a capacity of 7.35MW, which consists of 36 Wind Turbines each with the capacity of 200kW and 225kW. The present annual energy generation of the wind farm is 7350MWhr with the plant load factor of 11.41%. The intent of this study is to predict the annual energy output of the wind farm after the repowering using WAsP (Wind Atlas Analysis Application Program). Further this study analyses the power quality issues of the various Wind Turbines. In addition, the main feeder, in which the wind farm which is taken for the study also modeled and the impact on power quality due to repowering also studied. Simulations were carried out using MATLAB. The results are analyzed to understand the significance of repowering to overcome the energy crisis of the nation since the best locations for wind in India are occupied by old wind turbines. The following are the observations and conclusions from the above study. Plant load factor (PLF) increased to 24 %, Energy yield increased to more than 4 times and the capacity of the wind farm became double. And in the view of power quality, comparing to the existing Feeder, Repowered Feeder having less reactive power consumption, voltage variations and flickers except the harmonic distortion. (Author)

Economic Dispatch of the Low-Carbon Green Certificate with Wind Farms Based on Fuzzy Chance Constraints

Directory of Open Access Journals (Sweden)

Xiuyun Wang

2018-04-01

Full Text Available As the low-carbon economy continues to expand, wind power, as one form of clean energy, promotes the low-carbon power development process. In this paper, a multi-objective environmental economic dispatch (EED model is proposed considering multiple uncertainties of the system. Carbon trading costs and green certificate trading costs are introduced into the economic costs. Meanwhile, the objective function of pollutant emissions is taken into account in the model, which can further promote the reduction of pollutant emissions in the system scheduling. The output of wind turbines is uncertain and volatile, so it brings new challenges to the power system EED once the large-scale wind power accesses the power grid. For the multiple uncertainties of the system, fuzzy chance-constrained programming is introduced, and the output of the wind turbines and the load are regarded as fuzzy variables. We use the clear equivalence forms to clarify the fuzzy chance constraints. The improved multi-objective standard particle swarm optimization (SPSO algorithm is used to solve the optimization problem effectively. The feasibility and effectiveness of the proposed model and algorithm are verified by an example of a 10-unit system with two wind farms.

Performance of a 1-micron, 1-joule Coherent Launch Site Atmospheric Wind Sounder

Science.gov (United States)

Hawley, James G.; Targ, Russell; Bruner, Richard; Henderson, Sammy W.; Hale, Charles P.; Vetorino, Steven; Lee, R. W.; Harper, Scott; Khan, Tayyab

1992-01-01

The paper describes the design and performance of the Coherent Launch Site Atmospheric Wind Sounder (CLAWS), which is a test and demonstration program designed for monitoring winds with a solid-state lidar in real time for the launch site vehicle guidance and control application. Analyses were conducted to trade off CO2 (9.11- and 10.6-microns), Ho:YAG (2.09 microns), and Nd:YAG (1.06-micron) laser-based lidars. The measurements set a new altitude record (26 km) for coherent wind measurements in the stratosphere.

Does wind power amount to a luxury in France?

International Nuclear Information System (INIS)

Brassard, G.

2010-01-01

The avoided costs to the French electrical system thanks to wind power generation should be calculated by estimating avoided domestic generation costs rather than by using the cost of contracts traded on international exchanges, as is currently done by regulatory authorities. Up to now, wind power has basically displaced thermal power. The French Energy Regulatory Commission has feared that, in the future nuclear energy and thermal power could be equally substituted by wind power. Excess power capacity might induce authorities to postpone development of additional nuclear and renewable facilities. However, barring a collapse of electricity requirements in Europe, it is expected that electricity surpluses will be exported to neighboring networks. In the eventuality of increasing world energy prices, wind power would generate significant savings or the French electrical system, as the cost of wind power will be stable over the 15 year mandatory contracts. After taking account of external costs, wind-power on the French mainland is competitive with all other sources of electricity. With this conditions wind power is likely to play a significant and long term role in the French power generation mix. (author)

Round-the-year security analysis with large-scale wind power integration

NARCIS (Netherlands)

Ciupuliga, A.R.; Gibescu, M.; Pelgrum, E.; Jacobs, P.G.H.; Jansen, K.P.G.; Kling, W.L.

2012-01-01

The ongoing liberalization process together with the growing penetration of renewable energy sources (RES), e.g., wind power, require an internationally oriented transmission planning approach that considers the increased uncertainties in terms of trade, location of generation, and output of

Prescribed wind shear modelling with the actuator line technique

DEFF Research Database (Denmark)

Mikkelsen, Robert Flemming; Sørensen, Jens Nørkær; Troldborg, Niels

2007-01-01

A method for prescribing arbitrary steady atmospheric wind shear profiles combined with CFD is presented. The method is furthermore combined with the actuator line technique governing the aerodynamic loads on a wind turbine. Computation are carried out on a wind turbine exposed to a representative...

Wind loads on solar energy roofs

NARCIS (Netherlands)

Geurts, C.P.W.; Bentum, C.A. van

2007-01-01

This paper presents an overview of the wind loads on roofs, equipped with solar energy products, so called Active Roofs. Values given in this paper have been based on wind tunnel and full scale measurements, carried out at TNO, and on an interpretation of existing rules and guidelines. The results

The Wind Energy programme - SFOE Research Programme 2000 - 2003; Programm Wind. Konzept BFE-Forschungsprogramm 'Wind' 2000 - 2003

Energy Technology Data Exchange (ETDEWEB)

Horbaty, R.

2001-07-01

This document, issued by the Swiss Federal Office of Energy (SFOE) describes the concept behind the Swiss wind energy programme. The first part of the report discusses the origins and development of the wind energy programme in Switzerland, discussing the importance of wind energy and policy matters associated with its promotion. The experience gained during the previous research programmes is reviewed. The degree to which targets were reached, promotional activities, the central government's own wind energy activities and the results of a programme evaluation are discussed. Lists of projects that have been realised and activities that have been carried out are presented and positive and negative influences on development are noted. A second part is dedicated to the goals of the wind energy programme in terms of target figures for the year 2010 and the strategies chosen to reach these goals, including pilot and demonstration projects (P and D) and promotional activities. Details of the P and D programme including lists of wind-power projects to be supported, the priorities that have been set and information and further education that is to be provided, are given. New activities in the wind power area such as the development of new type of wind turbine especially suited to alpine conditions are discussed. The role of the Swiss Association for Wind Energy 'Suisse Eole' as a network-partner in the wind energy programme is discussed. An appendix provides details of wind energy projects in Switzerland, market partners and customers. The results of a survey made of wind energy activities at Swiss institutes of higher education are presented.

Wind's share in global energy markets

International Nuclear Information System (INIS)

Madsen, B.T.

1997-01-01

The question of how great of a contribution wind power can really make to the world's energy needs is discussed. Emphasis up until recently has been mainly on improving wind turbine technology and siting practices as it is these that will provide an answer. The International Energy Agency predicts that world energy demand will increase by 30-50% by 2010. More countries than ever are either using wind power now or are preparing for its use. Wind power continues to improve its price competitiveness. There is enough wind to cover our energy needs many times over, according to some reports twice the world's electricity supply could be met by utilizing just 5-10% of areas identified as having average wind speeds of 5 m/s or greater - ignoring population centers, forests and specially protected areas. But a major limiting factor to utilizing the available wind resource is the established grid systems, which can only base 20% of supply on wind power. It is concluded that wind can contribute significantly to the world's energy needs in the next century and beyond. If wind, which has taken giant leaps in improving its competitiveness over the past 20 hears, can be a major energy contributor by early next century, other renewables such as solar and biomass might also evolve to become major contributors too. If so, renewables, including hydro, could conceivably cover 50% of our energy needs by the middle of the next century. Much will depend on decision-makers at the centers of power. For Europe and certain other areas of the world, policies governing cross-border trade of electricity as well as the framework for environmental protection related to energy production will determine the final outcome

Observations of neutral winds, wind shears, and wave structure during a sporadic-E/QP event

Directory of Open Access Journals (Sweden)

M. F. Larsen

2005-10-01

Full Text Available The second Sporadic E Experiment over Kyushu (SEEK-2 was carried out on 3 August 2002, during an active sporadic-E event that also showed quasi-periodic (QP echoes. Two rockets were launched into the event from Kagoshima Space Center in southern Japan 15 min apart. Both carried a suite of instruments, but the second rocket also released a trimethyl aluminum (TMA trail to measure the neutral winds and turbulence structure. In a number of earlier measurements in similar conditions, large winds and shears that were either unstable or close to instability were observed in the altitude range where the ionization layer occurred. The SEEK-2 wind measurements showed similar vertical structure, but unlike earlier experiments, there was a significant difference between the up-leg and down-leg wind profiles. In addition, wave or billow-like fluctuations were evident in the up-leg portion of the trail, while the lower portion of the down-leg trail was found to have extremely strong turbulence that led to a rapid break-up of the trail. The large east-west gradient in the winds and the strong turbulence have not been observed before. The wind profiles and shears, as well as the qualitative characteristics of the strong turbulence are presented, along with a discussion of the implications of the dynamical features. Keywords. Ionosphere (Mid-latitude ionosphere; Ionospheric irregularities; Electric field and currents

Wind energy in Italy: state of the art and prospects

International Nuclear Information System (INIS)

Togni, S.

2009-01-01

Among renewable energy sources wind energy has the greatest potential as well as good prospects even in occupational terms. Yet a solution is still to be found to problems related to plant authorization procedures, inadequacy of the national electric grid, regularisation of trading authorisation procedures. [it

Monitoring the Efficiency of Budget Management of Trade Enterprises in Ukraine

Directory of Open Access Journals (Sweden)

Frolova Larysa V

2016-08-01

Full Text Available The article justifies the actuality of carrying out the monitoring of budget management efficiency at trade enterprises in Ukraine. It has been found that the efficiency of each trade enterprise management system, in particular the efficiency of budget management system, is determined by several factors, among which there considered the enterprise business profile, the competitive situation in the market and the standard of living of the population. The efficiency of budget management and, as a result, the efficiency of trade enterprises’ activity is reflected in the results of the effectiveness of the main indicators of the financial budgets of enterprises. Therefore, using the method of fuzzy sets, there carried out an integral evaluation of the efficiency of budget management based on the efficiency of financial budgets: the budget revenues and expenditures, cash flow budget and budgeted balance sheet. The study is carried out for Ukraine as a whole, and its most developed regions.

Two LQRI based Blade Pitch Controls for Wind Turbines

Directory of Open Access Journals (Sweden)

Yoonsu Nam

2012-06-01

Full Text Available As the wind turbine size has been increasing and their mechanical components are built lighter, the reduction of the structural loads becomes a very important task of wind turbine control in addition to maximum wind power capture. In this paper, we present a separate set of collective and individual pitch control algorithms. Both pitch control algorithms use the LQR control technique with integral action (LQRI, and utilize Kalman filters to estimate system states and wind speed. Compared to previous works in this area, our pitch control algorithms can control rotor speed and blade bending moments at the same time to improve the trade-off between rotor speed regulation and load reduction, while both collective and individual pitch controls can be designed separately. Simulation results show that the proposed collective and individual pitch controllers achieve very good rotor speed regulation and significant reduction of blade bending moments.

Adaptive pitch control for load mitigation of wind turbines

Science.gov (United States)

Yuan, Yuan; Tang, J.

2015-04-01

In this research, model reference adaptive control is examined for the pitch control of wind turbines that may suffer from reduced life owing to extreme loads and fatigue when operated under a high wind speed. Specifically, we aim at making a trade-off between the maximum energy captured and the load induced. The adaptive controller is designed to track the optimal generator speed and at the same time to mitigate component loads under turbulent wind field and other uncertainties. The proposed algorithm is tested on the NREL offshore 5-MW baseline wind turbine, and its performance is compared with that those of the gain scheduled proportional integral (GSPI) control and the disturbance accommodating control (DAC). The results show that the blade root flapwise load can be reduced at a slight expense of optimal power output. The generator speed regulation under adaptive controller is better than DAC.

Advanced Offshore Wind Energy - Atlantic Consortium

Energy Technology Data Exchange (ETDEWEB)

Kempton, Willett

2015-11-04

This project developed relationships among the lead institution, U of Delaware, wind industry participants from 11 companies, and two other universities in the region. The participating regional universities were University of Maryland and Old Dominion University. Research was carried out in six major areas: Analysis and documentation of extreme oceanic wind events & their impact on design parameters, calibration of corrosivity estimates measured on a coastal turbine, measurment and modeling of tower structures, measurement and modeling of the tribology of major drive components, and gearbox conditioning monitoring using acoustic sensors. The project also had several educational goals, including establishing a course in wind energy and training graduate students. Going beyond these goals, three new courses were developed, a graduate certificate program in wind power was developed and approved, and an exchange program in wind energy was established with Danish Technical University. Related to the installation of a Gamesa G90 turbine on campus and a Gamesa-UD research program established in part due to this award, several additional research projects have been carried out based on mutual industry-university interests, and funded by turbine revenues. This award and the Gamesa partnership have jointly led to seven graduate students receiving full safety and climb training, to become “research climbers” as part of their wind power training, and contributing to on-turbine research. As a result of the educational program, already six graduate students have taken jobs in the US wind industry.

Evaluation of the DeepWind concept

DEFF Research Database (Denmark)

Schmidt Paulsen, Uwe; Borg, Michael; Gonzales Seabra, Luis Alberto

The report describes the DeepWind 5 MW conceptual design as a baseline for results obtained in the scientific and technical work packages of the DeepWind project. A comparison of DeepWi nd with existing VAWTs and paper projects are carried out and the evaluation of the concept in terms of cost...

Optimisation Sizing of Hybrid Wind-Diesel Systems using Linear Programming Technique

OpenAIRE

Gan, Leong Kit; Shek, Jonathan; Mueller, Markus

2014-01-01

Despite the great potential of hybrid wind-diesel system in supplying energy to remote or island communities, sizing the system components have been a challenging problem for many project managers due to the reliance on various factors. This work considers utilising a fixed speed wind turbine (induction generator) in the hybrid system. It requires energy for start-up operation and this work takes into account for sizing the battery storage. In addition, the trade-off between the number of bat...

Pre-Feasibility Study of 80MW Onshore Wind Farm

Directory of Open Access Journals (Sweden)

Muhammad Shoaib Almas

2014-10-01

Full Text Available This paper discusses a pre-feasibility study of 80MW onshore wind farm in the KPK (Khyber Pakhtunkhwa province previously known as NWFP (North West Frontier Province of Pakistan. The realistic data of wind speed is collected from Laboratory of Meteorology & Climatology (University of the Punjab to study the feasibility of wind farm. Detailed analysis of wind turbines from four different manufacturers is carried out together with justifications of selecting a particular wind turbine. Issues related to site selection, wind farm civil foundation, recommendations for a particular choice of tower along with environmental effects are presented. Wind data analysis is carried out by using WINDROSE PRO software to determine the resultant direction of wind at the selected site for wind farm layout. The wind distribution at hub height of the wind turbine is calculated and is used to compute annual power production by the wind farm using power curves of the wind turbine. Electrical network integration issues of wind farm to the external grid are studied and the optimum point of connection is proposed. Finally, economic analysis of the whole wind farm project depending upon the LCC (Life Cycle Cost Analysis is presented and the feasibility of the project from the investor?s point of view is identified. The study concludes that the cost per kilowatt hour of electricity generated by this wind power plant will be 10.4 PKR/kWh and the payback period for the whole project is about 11.2 years

The solar wind in time: a change in the behaviour of older winds?

Science.gov (United States)

O'Fionnagáin, D.; Vidotto, A. A.

2018-05-01

In this paper, we model the wind of solar analogues at different ages to investigate the evolution of the solar wind. Recently, it has been suggested that winds of solar type stars might undergo a change in properties at old ages, whereby stars older than the Sun would be less efficient in carrying away angular momentum than what was traditionally believed. Adding to this, recent observations suggest that old solar-type stars show a break in coronal properties, with a steeper decay in X-ray luminosities and temperatures at older ages. We use these X-ray observations to constrain the thermal acceleration of winds of solar analogues. Our sample is based on the stars from the `Sun in Time' project with ages between 120 and 7000 Myr. The break in X-ray properties leads to a break in wind mass-loss rates (\\dot{M}) at roughly 2 Gyr, with \\dot{M} (t 2 Gyr) ∝ t-3.9. This steep decay in \\dot{M} at older ages could be the reason why older stars are less efficient at carrying away angular momentum, which would explain the anomalously rapid rotation observed in older stars. We also show that none of the stars in our sample would have winds dense enough to produce thermal emission above 1-2 GHz, explaining why their radio emissions have not yet been detected. Combining our models with dynamo evolution models for the magnetic field of the Earth, we find that, at early ages (≈100 Myr), our Earth had a magnetosphere that was three or more times smaller than its current size.

A comprehensive atlas of wind farms in France

International Nuclear Information System (INIS)

Ducuing, S.; Guillier, A.; Guichard, M.A.

2015-01-01

This article reports all the wind farms that have been carried out or are in project in France at the date of may 2015. All these installations represent an installed capacity of 13.817 MW including 3.524 MW that are in project (they are expected to enter into service during the next 3 years) and 434 MW that have been carried out during the first 5 months of 2015. A total of 1148 wind farms are reported. For each wind farm the following information is given: the name of the operator, the power output, the number of turbines, the name of the turbine manufacturer and the commissioning date. (A.C.)

The Feasibility of Utilizing Wind Energy in Commercial Buildings With Special Reference to the Kingdom of Bahrain

Science.gov (United States)

Abdulrahim Saeed, Saeed

2017-11-01

This article shall investigate the feasibility of utilizing wind energy for commercial buildings with special reference to the Kingdom of Bahrain. Bahrain World Trade Center which was built in 2008, is located in the city of Manama. The fifty-story complex contains identical twin towers that rise over 240 meters in height. The towers are connected by three bridges which hold three turbines each 29 meters long. The three turbines were originally design to provide electric energy required for lighting. The Bahrain World Trade Center was selected as a case study to investigate the feasibility of utilizing wind energy technologies in skyscrapers with special reference to the Kingdom of Bahrain. It is hoped that the findings and conclusion of the study shall be of some value for future utilization of wind energy in the GCC countries and the world at large.

Stellar wind theory

International Nuclear Information System (INIS)

Summers, D.

1980-01-01

The theory of stellar winds as given by the equations of classical fluid dynamics is considered. The equations of momentum and energy describing a steady, spherically symmetric, heat-conducting, viscous stellar wind are cast in a dimensionless form which involves a thermal conduction parameter E and a viscosity parameter γ. An asymptotic analysis is carried out, for fixed γ, in the cases E→O and E→infinity (corresponding to small and large thermal conductivity, respectively), and it is found that it is possible to construct critical solutions for the wind velocity and temperature over the entire flow. The E→O solution represents a wind which emanates from the star at low, subsonic speeds, accelerates through a sonic point, and then approaches a constant asymptotic speed, with its temperature varying as r/sup -4/3/ at large distances r from the star; the E→infinity solution represents a wind which, after reaching an approximately constant speed, with temperature varying as r/sup -2/7/, decelerates through a diffuse shock and approaches a finite pressure at infinity. A categorization is made of all critical stellar wind solutions for given values of γ and E, and actual numerical examples are given. Numerical solutions are obtained by integrating upstream 'from infinity' from initial values of the flow parameters given by appropriate asymptotic expansions. The role of viscosity in stellar wind theory is discussed, viscous and inviscid stellar wind solutions are compared, and it is suggested that with certain limitations, the theory presented may be useful in analyzing winds from solar-type stars

Power Performance Verification of a Wind Farm Using the Friedman's Test.

Science.gov (United States)

Hernandez, Wilmar; López-Presa, José Luis; Maldonado-Correa, Jorge L

2016-06-03

In this paper, a method of verification of the power performance of a wind farm is presented. This method is based on the Friedman's test, which is a nonparametric statistical inference technique, and it uses the information that is collected by the SCADA system from the sensors embedded in the wind turbines in order to carry out the power performance verification of a wind farm. Here, the guaranteed power curve of the wind turbines is used as one more wind turbine of the wind farm under assessment, and a multiple comparison method is used to investigate differences between pairs of wind turbines with respect to their power performance. The proposed method says whether the power performance of the specific wind farm under assessment differs significantly from what would be expected, and it also allows wind farm owners to know whether their wind farm has either a perfect power performance or an acceptable power performance. Finally, the power performance verification of an actual wind farm is carried out. The results of the application of the proposed method showed that the power performance of the specific wind farm under assessment was acceptable.

Health-aware Model Predictive Control of Wind Turbines using Fatigue Prognosis

DEFF Research Database (Denmark)

Sardi, Hector Eloy Sanchez; Escobet, Teressa; Puig, Vicenc

2015-01-01

management module with the control provides a mechanism for the wind turbine to operate safely and optimize the trade-off between components life and energy production. The research presented in this paper explores the integration of model predictive control (MPC) with fatigue-based prognosis approach...

Evolution of international trade and investment networks

Science.gov (United States)

Zhang, Shuhong; Wang, Lin; Liu, Zhixin; Wang, Xiaofan

2016-11-01

In this paper, an evolving two-layer international economy network (IEN) consisting of international trade network (ITN) and international investment network (IIN) as layers, is constructed to investigate the world economy from 2001 to 2010. First, the structure analysis shows that the average partner numbers for both trade and investment are increasing year by year, and the average volume has a significant decrease in 2008 for investment and 2009 for trade. The IIN has longer average path length and dramatically lower edge density compared with the ITN, yet its clustering coefficient is larger in all years. Then, the regional relativity indicates that the longer the distance between two countries, the smaller trade and investment volumes they carry in are general, and the impact of the geographical distance gradually reduces as time goes on. Furthermore, the countries and regions are ranked by Pagerank in ITN, IIN and IEN to illustrate the roles they played. And finally, community structures are detected to visualize the global economic landscape, with countries and regions in the same community ranked according to the total volume of trade or investment.

Isolated systems with wind power. An implementation guideline

DEFF Research Database (Denmark)

Clausen, Niels-Erik; Bindner, Henrik W.; Frandsen, Sten Tronæs

2001-01-01

The overall objective of this research project is to study the development of methods and guidelines rather than "universal solutions" for the use of wind energy in isolated communities. So far most studies of isolated systems with wind power have beencase-oriented and it has proven difficult...... feasibility of isolated power supply systems with wind energy. General guidelines and checklists on which facts and data are needed to carry out a projectfeasibility analysis are presented as well as guidelines how to carry out the project feasibility study and the environmental analysis. The report outlines...... the results of the project as a set of proposed guidelines to be applied when developing a projectcontaining an application of wind in an isolated power system. It is the author's hope that this will facilitate the development of projects and enhance electrification of small rural communities in developing...

Neighborhood Effects in Wind Farm Performance: A Regression Approach

Directory of Open Access Journals (Sweden)

Matthias Ritter

2017-03-01

Full Text Available The optimization of turbine density in wind farms entails a trade-off between the usage of scarce, expensive land and power losses through turbine wake effects. A quantification and prediction of the wake effect, however, is challenging because of the complex aerodynamic nature of the interdependencies of turbines. In this paper, we propose a parsimonious data driven regression wake model that can be used to predict production losses of existing and potential wind farms. Motivated by simple engineering wake models, the predicting variables are wind speed, the turbine alignment angle, and distance. By utilizing data from two wind farms in Germany, we show that our models can compete with the standard Jensen model in predicting wake effect losses. A scenario analysis reveals that a distance between turbines can be reduced by up to three times the rotor size, without entailing substantial production losses. In contrast, an unfavorable configuration of turbines with respect to the main wind direction can result in production losses that are much higher than in an optimal case.

From probabilistic forecasts to statistical scenarios of short-term wind power production

DEFF Research Database (Denmark)

Pinson, Pierre; Papaefthymiou, George; Klockl, Bernd

2009-01-01

on the development of the forecast uncertainty through forecast series. However, this additional information may be paramount for a large class of time-dependent and multistage decision-making problems, e.g. optimal operation of combined wind-storage systems or multiple-market trading with different gate closures......Short-term (up to 2-3 days ahead) probabilistic forecasts of wind power provide forecast users with highly valuable information on the uncertainty of expected wind generation. Whatever the type of these probabilistic forecasts, they are produced on a per horizon basis, and hence do not inform....... This issue is addressed here by describing a method that permits the generation of statistical scenarios of short-term wind generation that accounts for both the interdependence structure of prediction errors and the predictive distributions of wind power production. The method is based on the conversion...

Mesoscale modeling of smoke transport over Central Africa: influences of trade winds, subtropical high, ITCZ and vertical statistics

Science.gov (United States)

Yang, Z.; Wang, J.; Hyer, E. J.; Ichoku, C. M.

2012-12-01

A fully-coupled meteorology-chemistry-aerosol model, Weather Research and Forecasting model with Chemistry (WRF-Chem), is used to simulate the transport of smoke aerosol over the Central Africa during February 2008. Smoke emission used in this study is specified from the Fire Locating and Modeling of Burning Emissions (FLAMBE) database derived from Moderate Resolution Imaging Spectroradiometer (MODIS) fire products. Model performance is evaluated using MODIS true color images, measured Aerosol Optical Depth (AOD) from space-borne MODIS (550 nm) and ground-based AERONET (500 nm), and Cloud-Aerosol Lidar data with Orthogonal Polarization (CALIOP) level 1 and 2 products. The simulated smoke transport is in good agreement with the validation data. Analyzing from three smoke events, smoke is constrained in a narrow belt between the Equator and 10°N near the surface, with the interplay of trade winds, subtropical high, and ITCZ. At the 700 hpa level, smoke expands farther meridionally. Topography blocks the smoke transport to the southeast of study area, because of high mountains located near the Great Rift Valley region. The simulation with injection height of 650 m is consistent with CALIOP measurements. The particular phenomenon, aerosol above cloud, is studied statistically from CALIOP observations. The total percentage of aerosol above cloud is about 5%.

The effect of wind turbines on the bird population at Blyth Harbour

International Nuclear Information System (INIS)

Still, D.; Little, B.; Lawrence, S.

1996-01-01

Bird monitoring was carried out at Blyth Harbour Wind Farm which consists of a line of nine 300kW wind turbines distributed at 200m intervals along a 1.2km breakwater. The harbour breakwater is designated as part of a Site of Special Scientific Interest as it supports an internationally important winter population of Purple Sandpipers. The Blyth estuary is to be designated as part of a Special Protection Area under the EC Habitats Directive and as part of a proposed RAMSAR site due to its peak periods up to c.5000 bird movements/day occur adjacent to the windfarm. Mortality surveys (at one week intervals) were carried out on adjacent beaches to the wind farm in order to assess the background numbers of bird corpses and locate wind farm casualties. Supplementary mortality searches were carried out near power lines less than 2.5 km upstream from the wind farm. Tests of the efficiency of the mortality surveys have been carried out in order to assess the likely impact on the local bird populations. In spite of the large bird population supported by the harbour and its close proximity to the wind farm there have been relatively few collision victims (31) since the windfarm was commissioned. This is equivalent to less than 1.34 bird strike/wind turbine per annum. (author)

Wind-governed flight altitudes of nocturnal spring migrants over the ...

African Journals Online (AJOL)

Flight costs make up a large proportion of energy expenditure during migration and are strongly dependent on atmospheric conditions aloft. Birds crossing the Sahara can take advantage of the fairly reliable trade-wind regime. In our study, we investigated whether birds adapt flight altitude to minimise energy or water loss.

Impact of wind turbine noise in the Netherlands.

Science.gov (United States)

Verheijen, Edwin; Jabben, Jan; Schreurs, Eric; Smith, Kevin B

2011-01-01

The Dutch government aims at an increase of wind energy up to 6 000 MW in 2020 by placing new wind turbines on land or offshore. At the same time, the existing noise legislation for wind turbines is being reconsidered. For the purpose of establishing a new noise reception limit value expressed in L den , the impact of wind turbine noise under the given policy targets needs to be explored. For this purpose, the consequences of different reception limit values for the new Dutch noise legislation have been studied, both in terms of effects on the population and regarding sustainable energy policy targets. On the basis of a nation-wide noise map containing all wind turbines in The Netherlands, it is calculated that 3% of the inhabitants of The Netherlands are currently exposed to noise from wind turbines above 28 dB(A) at the faηade. Newly established dose-response relationships indicate that about 1500 of these inhabitants are likely to be severely annoyed inside their dwellings. The available space for new wind turbines strongly depends on the noise limit value that will be chosen. This study suggests an outdoor A-weighted reception limit of L den = 45 dB as a trade-off between the need for protection against noise annoyance and the feasibility of national targets for renewable energy.

Optimal wind power deployment in Europe. A portfolio approach

International Nuclear Information System (INIS)

Roques, Fabien; Hiroux, Celine; Saguan, Marcelo

2010-01-01

Geographic diversification of wind farms can smooth out the fluctuations in wind power generation and reduce the associated system balancing and reliability costs. The paper uses historical wind production data from five European countries (Austria, Denmark, France, Germany, and Spain) and applies the Mean-Variance Portfolio theory to identify cross-country portfolios that minimise the total variance of wind production for a given level of production. Theoretical unconstrained portfolios show that countries (Spain and Denmark) with the best wind resource or whose size contributes to smoothing out the country output variability dominate optimal portfolios. The methodology is then elaborated to derive optimal constrained portfolios taking into account national wind resource potential and transmission constraints and compare them with the projected portfolios for 2020. Such constraints limit the theoretical potential efficiency gains from geographical diversification, but there is still considerable room to improve performance from actual or projected portfolios. These results highlight the need for more cross-border interconnection capacity, for greater coordination of European renewable support policies, and for renewable support mechanisms and electricity market designs providing locational incentives. Under these conditions, a mechanism for renewables credits trading could help aligning wind power portfolios with the theoretically efficient geographic dispersion. (author)

Can the future EU ETS support wind energy investments?

International Nuclear Information System (INIS)

Blanco, Maria Isabel; Rodrigues, Gloria

2008-01-01

This article discusses how the future Emissions Trading Scheme legislation should be designed to allow the European Union to comply with the 20% CO 2 emissions reduction target, while at the same time promoting wind energy investments. We examine whether CO 2 prices could eventually replace the existing support schemes for wind and if they adequately capture its benefits. The analysis also looks at the effectiveness of the clean development and joint implementation mechanisms to trigger wind projects and technology transfer in developing countries. We find out that climate policy is unlikely to provide sufficient incentives to promote wind power, and that other policies should be used to internalise the societal benefits that accrue from deploying this technology: CO 2 prices can only reflect the beneficial impact of wind on climate change but not its contribution to the security of supply or employment creation. A minimum price of around Euro 40/tCO 2 should be attained to maintain present support levels for wind and this excludes income risks and intermediation costs. Finally, CDM improves the return rate of wind energy projects in third countries, but it is the local institutional framework and the long-term stability of the CO 2 markets that matters the most

Can the future EU ETS support wind energy investments?

Energy Technology Data Exchange (ETDEWEB)

Blanco, Maria Isabel [Department of Economic Analysis, Faculty of Economics,University of Alcala, Plaza de la Victoria 3, 28002 Alcala de Henares, Madrid (Spain); Rodrigues, Gloria [European Wind Energy Association, EWEA, Rue D' Arlon 63-65, 1040 Brussels (Belgium)

2008-04-15

This article discusses how the future Emissions Trading Scheme legislation should be designed to allow the European Union to comply with the 20% CO{sub 2} emissions reduction target, while at the same time promoting wind energy investments. We examine whether CO{sub 2} prices could eventually replace the existing support schemes for wind and if they adequately capture its benefits. The analysis also looks at the effectiveness of the clean development and joint implementation mechanisms to trigger wind projects and technology transfer in developing countries. We find out that climate policy is unlikely to provide sufficient incentives to promote wind power, and that other policies should be used to internalise the societal benefits that accrue from deploying this technology: CO{sub 2} prices can only reflect the beneficial impact of wind on climate change but not its contribution to the security of supply or employment creation. A minimum price of around EUR40/tCO{sub 2} should be attained to maintain present support levels for wind and this excludes income risks and intermediation costs. Finally, CDM improves the return rate of wind energy projects in third countries, but it is the local institutional framework and the long-term stability of the CO{sub 2} markets that matters the most. (author)

Analytical methods for wind persistence: Their application in assessing the best site for a wind farm in the State of Veracruz, Mexico

Energy Technology Data Exchange (ETDEWEB)

Cancino-Solorzano, Yoreley; Gutierrez-Trashorras, Antonio J.; Xiberta-Bernat, Jorge [Departamento de Energia, Escuela Tecnica Superior de Ingenieros de Minas, Universidad de Oviedo., c/ Independencia, 13, 2a Planta, 33004 Oviedo (Spain)

2010-12-15

The properties of wind persistence are an essential parameter in carrying out a complete analysis of possible sites for a wind farm. This parameter can be defined as a measure of the mean duration of wind speed within a given interval of values for a concrete site. In this study the persistence properties are evaluated from the methods based on the autocorrelation function, conditional probability and the curves of speed duration, used satisfactorily by other authors. The statistical analysis of the series of useful persistence is also carried out to validate the results obtained. These methods have been applied to hourly data of wind speed corresponding to five Weather Stations (WS) in the State of Veracruz, Mexico in the period 1995-2006. The results obtained indicate that the coastal areas have the best properties of wind speed persistence and are, therefore, the most indicated for the generation of electricity from this renewable energy source. (author)

European wind turbine testing procedure developments. Task 1: Measurement method to verify wind turbine performance characteristics

DEFF Research Database (Denmark)

Hunter, R.; Friis Pedersen, Troels; Dunbabin, P.

2001-01-01

There is currently significant standardisation work ongoing in the context of wind farm energy yield warranty assessment and wind turbine power performance testing. A standards maintenance team is revising the current IEC (EN) 61400-12 Ed 1 standard forwind turbine power performance testing....... The standard is being divided into four documents. Two of them are drafted for evaluation and verification of complete wind farms and of individual wind turbines within wind farms. This document, and the project itdescribes, has been designed to help provide a solid technical foundation for this revised...... standard. The work was wide ranging and addressed 'grey' areas of knowledge, regarding existing methodologies or to carry out basic research in support offundamentally new procedures. The work has given rise to recommendations in all areas of the work, including site calibration procedures, nacelle...

Wind energy research activities of the Dutch Electricity Generating Board

International Nuclear Information System (INIS)

Halberg, N.

1990-01-01

The varying degrees of penetration of wind energy conversion systems (WECs) into the Dutch electricity generating system has been examined. A simulation has been carried out using wind data recorded at 6 sites spread across the area of interest in the Netherlands. The recorded wind data has been used in conjunction with a production costing model normally used by Sep (the Dutch Electricity Generating Board) for planning purposes. This model was modified to give a correct assessment of the quantity and value of fuel savings made by WECs. System studies were carried out for the year 2000 for zero wind penetration and for three distinctive penetration degrees of WECs, namely 5%, 10% and 15%. After incorporation of the WECS capacity, adjustments were made to the basic plant mix to allow the capacity credit WECs. Separate production cost simulations were executed for each distinct WECS capacity factor. Economic assessments were carried out using standard procedures. Except for the unpredictable development of fuel prices, the capital costs of the WECs proved to be the determinant for the economic viability of wind power. Significant improvements in costs and performance, as may be achieved through additional technological advances, are needed to made wind power competitive in widespread utility applications. (Author)

Impact of wind power uncertainty forecasting on the market integration of wind energy in Spain

International Nuclear Information System (INIS)

González-Aparicio, I.; Zucker, A.

2015-01-01

Highlights: • Reduction wind power forecasting uncertainty for day ahead and intraday markets. • Statistical relationship between total load and wind power generation. • Accurately forecast expected revenues from wind producer’s perspective. - Abstract: The growing share of electricity production from variable renewable energy sources increases the stochastic nature of the power system. This has repercussions on the markets for electricity. Deviations from forecasted production schedules require balancing of a generator’s position within a day. Short term products that are traded on power and/or reserve markets have been developed for this purpose, providing opportunities to actors who can offer flexibility in the short term. The value of flexibility is typically modelled using stochastic scenario extensions of dispatch models which requires, as a first step, understanding the nature of forecast uncertainties. This study provides a new approach for determining the forecast errors of wind power generation in the time period between the closure of the day ahead and the opening of the first intraday session using Spain as an example. The methodology has been developed using time series analysis for the years 2010–2013 to find the explanatory variables of the wind error variability by applying clustering techniques to reduce the range of uncertainty, and regressive techniques to forecast the probability density functions of the intra-day price. This methodology has been tested considering different system actions showing its suitability for developing intra-day bidding strategies and also for the generation of electricity generated from Renewable Energy Sources scenarios. This methodology could help a wind power producer to optimally bid into the intraday market based on more accurate scenarios, increasing their revenues and the system value of wind.

European wind turbine testing procedure developments. Task 1: Measurement method to verify wind turbine performance characteristics

Energy Technology Data Exchange (ETDEWEB)

Hunter, R.; Friis Pedersen, T.; Dunbabin, P.; Antoniou, I.; Frandsen, S.; Klug, H.; Albers, A.; Lee, W.K.

2001-01-01

There is currently significant standardisation work ongoing in the context of wind farm energy yield warranty assessment and wind turbine power performance testing. A standards maintenance team is revising the current IEC (EN) 61400-12 Ed 1 standard for wind turbine power performance testing. The standard is being divided into four documents. Two of them are drafted for evaluation and verification of complete wind farms and of individual wind turbines within wind farms. This document, and the project it describes, has been designed to help provide a solid technical foundation for this revised standard. The work was wide ranging and addressed 'grey' areas of knowledge, regarding existing methodologies or to carry out basic research in support of fundamentally new procedures. The work has given rise to recommendations in all areas of the work, including site calibration procedures, nacelle anemometry, multi-variate regression analysis and density normalisation. (au)

Offshore Wind Farm Clusters - Towards new integrated Design Tool

DEFF Research Database (Denmark)

Hasager, Charlotte Bay; Réthoré, Pierre-Elouan; Peña, Alfredo

In EERA DTOC testing of existing wind farm wake models against four validation data test sets from large offshore wind farms is carried out. This includes Horns Rev-1 in the North Sea, Lillgrund in the Baltic Sea, Roedsand-2 in the Baltic Sea and from 10 large offshore wind farms in Northern Euro...

Energy from biomass. Summaries of the Biomass Projects carried out as part of the Department of Trade and Industry's New and Renewable Energy Programme. Vol. 5: straw, poultry litter and energy crops as energy sources

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-01-01

These volumes of summaries provide easy access to the many projects carried out in the Energy from Biomass programme area as part of the Department of Trade and Industry's New and Renewable Energy Programme. The summaries in this volume cover contractor reports on the subject published up to December 1997. (author)

Prospects of international trade in irradiated foods

International Nuclear Information System (INIS)

Loaharanu, P.

1990-01-01

Irradiation is gaining recognition as a physical process for reducing food losses, enhancing hygienic quality of food and facilitating food trade. At present, 36 countries have approved the use of irradiation for processing collectively over 40 food items either on an unconditional or restricted basis. Commercial use of irradiated foods and food ingredients is being carried out in 22 countries. Technology transfer on food irradiation is being intensified to local industry in different regions. Worldwide, a total of 40 commercial/demonstration irradiators available for treating foods have been or are being constructed. Acceptance and control of international trade in irradiated foods were discussed at the International Conference on the Acceptance, Control of and Trade in Irradiated Food, jointly convened by FAO, IAEA, WHO and ITC-UNCTAD/GATT in Geneva, Switzerland, 12-16 December 1988. An ''International Document on Food Irradiation'' was adopted by consensus at this Conference which will facilitate wider acceptance and control of international trade in irradiated foods. (author)

To trade or not to trade: Link prediction in the virtual water network

Science.gov (United States)

Tuninetti, Marta; Tamea, Stefania; Laio, Francesco; Ridolfi, Luca

2017-12-01

In the international trade network, links express the (temporary) presence of a commercial exchange of goods between any two countries. Given the dynamical behaviour of the trade network, where links are created and dismissed every year, predicting the link activation/deactivation is an open research question. Through the international trade network of agricultural goods, water resources are 'virtually' transferred from the country of production to the country of consumption. We propose a novel methodology for link prediction applied to the network of virtual water trade. Starting from the assumption of having links between any two countries, we estimate the associated virtual water flows by means of a gravity-law model using country and link characteristics as drivers. We consider the links with estimated flows higher than 1000 m3/year as active links, while the others as non-active links. Flows traded along estimated active links are then re-estimated using a similar but differently-calibrated gravity-law model. We were able to correctly model 84% of the existing links and 93% of the non-existing links in year 2011. It is worth to note that the predicted active links carry 99% of the global virtual water flow; hence, missed links are mainly those where a minimum volume of virtual water is exchanged. Results indicate that, over the period from 1986 to 2011, population, geographical distances between countries, and agricultural efficiency (through fertilizers use) are the major factors driving the link activation and deactivation. As opposed to other (network-based) models for link prediction, the proposed method is able to reconstruct the network architecture without any prior knowledge of the network topology, using only the nodes and links attributes; it thus represents a general method that can be applied to other networks such as food or value trade networks.

Dual stator winding variable speed asynchronous generator: optimal design and experiments

International Nuclear Information System (INIS)

Tutelea, L N; Deaconu, S I; Popa, G N

2015-01-01

In the present paper is carried out a theoretical and experimental study of dual stator winding squirrel cage asynchronous generator (DSWA) behavior in the presence of saturation regime (non-sinusoidal) due to the variable speed operation. The main aims are the determination of the relations of calculating the equivalent parameters of the machine windings to optimal design using a Matlab code. Issue is limited to three phase range of double stator winding cage-induction generator of small sized powers, the most currently used in the small adjustable speed wind or hydro power plants. The tests were carried out using three-phase asynchronous generator having rated power of 6 [kVA]. (paper)

Wind power in Arctic regions

International Nuclear Information System (INIS)

Lundsager, P.; Ahm, P.; Madsen, B.; Krogsgaard, P.

1993-07-01

Arctic or semi-arctic regions are often endowed with wind resources adequate for a viable production of electricity from the wind. Only limited efforts have so far been spent to introduce and to demonstrate the obvious synergy of combining wind power technology with the problems and needs of electricity generation in Arctic regions. Several factors have created a gap preventing the wind power technology carrying its full role in this context, including a certain lack of familiarity with the technology on the part of the end-users, the local utilities and communities, and a lack of commonly agreed techniques to adapt the same technology for Arctic applications on the part of the manufacturers. This report is part of a project that intends to contribute to bridging this gap. The preliminary results of a survey conducted by the project are included in this report, which is a working document for an international seminar held on June 3-4, 1993, at Risoe National Laboratory, Denmark. Following the seminar a final report will be published. It is intended that the final report will serve as a basis for a sustained, international effort to develop the wind power potential of the Arctic and semi-arctic regions. The project is carried out by a project group formed by Risoe, PA Energy and BTM Consult. The project is sponsored by the Danish Energy Agency of the Danish Ministry of Energy through grant no. ENS-51171/93-0008. (au)

Turbulent Flow Inside and Above a Wind Farm: A Wind-Tunnel Study

Directory of Open Access Journals (Sweden)

Leonardo P. Chamorro

2011-11-01

Full Text Available Wind-tunnel experiments were carried out to better understand boundary layer effects on the flow pattern inside and above a model wind farm under thermally neutral conditions. Cross-wire anemometry was used to characterize the turbulent flow structure at different locations around a 10 by 3 array of model wind turbines aligned with the mean flow and arranged in two different layouts (inter-turbine separation of 5 and 7 rotor diameters in the direction of the mean flow by 4 rotor diameters in its span. Results suggest that the turbulent flow can be characterized in two broad regions. The first, located below the turbine top tip height, has a direct effect on the performance of the turbines. In that region, the turbulent flow statistics appear to reach equilibrium as close as the third to fourth row of wind turbines for both layouts. In the second region, located right above the first one, the flow adjusts slowly. There, two layers can be identified: an internal boundary layer where the flow is affected by both the incoming wind and the wind turbines, and an equilibrium layer, where the flow is fully adjusted to the wind farm. An adjusted logarithmic velocity distribution is observed in the equilibrium layer starting from the sixth row of wind turbines. The effective surface roughness length induced by the wind farm is found to be higher than that predicted by some existing models. Momentum recovery and turbulence intensity are shown to be affected by the wind farm layout. Power spectra show that the signature of the tip vortices, in both streamwise and vertical velocity components, is highly affected by both the relative location in the wind farm and the wind farm layout.

Korea’s Trade Strategies for Mega Free Trade Agreements in Regional and Global Economic Integration

Directory of Open Access Journals (Sweden)

Sang-Chul Park

2016-12-01

Full Text Available Korea has developed rapidly since the 1960s. It is one of the four Asian tiger economies and a good model for developing countries. Korea shows the world how a developing country can develop its economy rapidly and become industrialized. Its development strategy has mainly been an export-oriented trade policy. As a result, its trade volume grew from $1 billion in 1966 to $1 trillion in 2011, which is a 1,000-fold increase within five decades. Since 2011, Korea has become one of seven countries with a trade volume over $1 trillion. However, the Korean economy has experienced turbulence as well as positive growth. It underwent severe economic crises such as the Asian financial crisis in 1997 and the global financial crisis in 2008. Its economy has been extremely vulnerable to the external economic environment, although it has improved and strengthened, particularly since the global financial crisis. During those two crises, the government carried out an appropriate trade policy with a strategic approach to upgrade its industrial structure and competitiveness in global markets. This article comprehensively discusses Korean trade policy and strategy over the last five decades, and how its national economy has developed rapidly. It also explores how the government sets its strategic targets in Asia and the Asia Pacific region. It considers two mega free trade agreements (FTAs — the Regional Comprehensive Economic Partnership and the Trans-Pacific Partnership — as new opportunities for further development. Therefore, it is wise to analyze these regional mega FTAs in order to maximize the national interest.

Fault diagnostics in power transformer model winding for different alpha values

Directory of Open Access Journals (Sweden)

G.H. Kusumadevi

2015-09-01

Full Text Available Transient overvoltages appearing at line terminal of power transformer HV windings can cause failure of winding insulation. The failure can be from winding to ground or between turns or sections of winding. In most of the cases, failure from winding to ground can be detected by changes in the wave shape of surge voltage appearing at line terminal. However, detection of insulation failure between turns may be difficult due to intricacies involved in identifications of faults. In this paper, simulation investigations carried out on a power transformer model winding for identifying faults between turns of winding has been reported. The power transformer HV winding has been represented by 8 sections, 16 sections and 24 sections. Neutral current waveform has been analyzed for same model winding represented by different number of sections. The values of α (‘α’ value is the square root of total ground capacitance to total series capacitance of winding considered for windings are 5, 10 and 20. Standard lightning impulse voltage (1.2/50 μs wave shape have been considered for analysis. Computer simulations have been carried out using software PSPICE version 10.0. Neutral current and frequency response analysis methods have been used for identification of faults within sections of transformer model winding.

Design Study of Fully Superconducting Wind Turbine Generators

DEFF Research Database (Denmark)

Song, Xiaowei (Andy); Mijatovic, Nenad; Jensen, Bogi Bech

2015-01-01

In this paper, two fully superconducting generators employing MgB2 armature winding, with YBCO and MgB2 field winding respectively, are presented and analyzed. The ac loss in armature winding is estimated, and a simple comparative study is carried out. The results show that both electromagnetic...... designs for fully superconducting generators are promising with respect to the power density. However, the cost of removing ac loss in armature winding is as high as $900 000. It is also noted that with the current price of YBCO tape, the generator employing MgB 2 field winding would have lower cost....

Wind loads on post-panamax container ship

DEFF Research Database (Denmark)

Andersen, Ingrid Marie Vincent

2013-01-01

An investigation of the influence of the container configuration on the deck of a 9000+ TEU container ship on wind forces has been carried out through a series of wind tunnel tests with a 1:450 scale model. An analysis of earlier studies was used to select a series of appropriate loading conditions...

Wind energy potential in Chile: Assessment of a small scale wind farm for residential clients

International Nuclear Information System (INIS)

Becerra, Miguel; Morán, José; Jerez, Alejandro; Cepeda, Francisco; Valenzuela, Miguel

2017-01-01

Highlights: • An assessment of a small scale wind farm was carried out. • Two Chilean locations were selected, which are geographically dissimilar. • The software tool selected for the project’s evaluation was HOMER. • All the project’s financial evaluations were negative. • Government policy tools and their applications were discussed. - Abstract: This work presents a techno-financial evaluation of two Chilean locations with promising wind potential: Laguna Verde placed in the central region of the country, and Porvenir in the southern region. A small scale wind farm was studied, considering a nominal electrical production capacity of 90 kW. This facility is comprised of three wind turbine models, all available in the national market. Currently, the tariff method used in Chile is the net billing scheme, where the energy bought and sold to the grid has different prices. The study is based on 300 hypothetical residential households. The software tool used to perform the assessment was the Hybrid Optimization of Multiple Energy Resources (HOMER). For all the scenarios the results showed a Net Present Cost (NPC), instead of a financial profit from the proposed projects. A sensitivity analysis was also carried out. From the group of variables studied, the NPC exhibited itself as more sensitive to the price of buying energy from the grid and to the annual average wind speed. Finally, a few government policies and their applications are discussed.

Power Performance Verification of a Wind Farm Using the Friedman’s Test

Science.gov (United States)

Hernandez, Wilmar; López-Presa, José Luis; Maldonado-Correa, Jorge L.

2016-01-01

In this paper, a method of verification of the power performance of a wind farm is presented. This method is based on the Friedman’s test, which is a nonparametric statistical inference technique, and it uses the information that is collected by the SCADA system from the sensors embedded in the wind turbines in order to carry out the power performance verification of a wind farm. Here, the guaranteed power curve of the wind turbines is used as one more wind turbine of the wind farm under assessment, and a multiple comparison method is used to investigate differences between pairs of wind turbines with respect to their power performance. The proposed method says whether the power performance of the specific wind farm under assessment differs significantly from what would be expected, and it also allows wind farm owners to know whether their wind farm has either a perfect power performance or an acceptable power performance. Finally, the power performance verification of an actual wind farm is carried out. The results of the application of the proposed method showed that the power performance of the specific wind farm under assessment was acceptable. PMID:27271628

Power Performance Verification of a Wind Farm Using the Friedman’s Test

Directory of Open Access Journals (Sweden)

Wilmar Hernandez

2016-06-01

Full Text Available In this paper, a method of verification of the power performance of a wind farm is presented. This method is based on the Friedman’s test, which is a nonparametric statistical inference technique, and it uses the information that is collected by the SCADA system from the sensors embedded in the wind turbines in order to carry out the power performance verification of a wind farm. Here, the guaranteed power curve of the wind turbines is used as one more wind turbine of the wind farm under assessment, and a multiple comparison method is used to investigate differences between pairs of wind turbines with respect to their power performance. The proposed method says whether the power performance of the specific wind farm under assessment differs significantly from what would be expected, and it also allows wind farm owners to know whether their wind farm has either a perfect power performance or an acceptable power performance. Finally, the power performance verification of an actual wind farm is carried out. The results of the application of the proposed method showed that the power performance of the specific wind farm under assessment was acceptable.

Power system reliability impacts of wind generation and operational reserve requirements

Directory of Open Access Journals (Sweden)

Esteban Gil

2015-06-01

Full Text Available Due to its variability, wind generation integration presents a significant challenge to power system operators in order to maintain adequate reliability levels while ensuring least cost operation. This paper explores the trade-off between the benefits associated to a higher wind penetration and the additional operational reserve requirements that they impose. Such exploration is valued in terms of its effect on power system reliability, measured as an amount of unserved energy. The paper also focuses on how changing the Value of Lost Load (VoLL can be used to attain different reliability targets, and how wind power penetration and the diversity of the wind energy resource will impact quality of supply (in terms of instances of unserved energy. The evaluation of different penetrations of wind power generation, different wind speed profiles, wind resource diversity, and different operational reserve requirements, is conducted on the Chilean Northern Interconnected System (SING using statistical modeling of wind speed time series and computer simulation through a 24-hour ahead unit commitment algorithm and a Monte Carlo simulation scheme. Results for the SING suggest that while wind generation can significantly reduce generation costs, it can also imply higher security costs to reach acceptable reliability levels.

Wind energy for a sustainable development

DEFF Research Database (Denmark)

Karagali, Ioanna; Hasager, Charlotte Bay; Sempreviva, Anna Maria

2014-01-01

of both the wind energy related research activities and the wind energy industry, as installed capacity has been increasing in most of the developed and developing countries. The DTU Wind Energy department carries the heritage of the Risø National Laboratory for Sustainable Energy by leading the research......Wind energy is on the forefront of sustainable technologies related to the production of electricity from green sources that combine the efficiency of meeting the demand for growth and the ethical responsibility for environmental protection. The last decades have seen an unprecedented growth...... developments in all sectors related to planning, installing and operating modern wind farms at land and offshore. With as many as 8 sections the department combines specialists at different thematic categories, ranging from meteorology, aeroelastic design and composite materials to electrical grids and test...

The current wind energy programme in Italy

International Nuclear Information System (INIS)

Ambrosini, G.; Foli, U.; Sesto, E.; Vigotti, R.

1991-01-01

In Italy, the main activities in the field of wind energy are carried out by two state-owned organizations, ENEA (Italian National Agency for New Technologies, Energy and the Environment) and ENEL (Italian National Electricity Board), and two major wind turbine generator manufacturers, Alenia/WEST and Riva Calzoni, within the framework of a national programme which is supervized by the Ministry of Industry and Commerce. The work currently under way concerns both wind power plant siting and the development and testing of Italian-made wind turbine generators ranging from 5 to 1500 kW in power. In addition, programmes aimed at constructing wind-farms made up of medium-sized machines (200-400 kW) have recently been launched

Anonymous electronic trading versus floor trading

OpenAIRE

Franke, Günter; Hess, Dieter

1995-01-01

This paper compares the attractiveness of floor trading and anonymous electronic trading systems. It is argued that in times of low information intensity the insight into the order book of the electronic trading system provides more valuable information than floor trading, but in times of high information intensity the reverse is true. Thus, the electronic system's market share in trading activity should decline in times of high information intensity. This hypothesis is tested by data on BUND...

The Empirical Analysis of Cigarette Tax Avoidance and Illicit Trade in Vietnam, 1998-2010

OpenAIRE

Nguyen, Minh Thac; Denniston, Ryan; Nguyen, Hien Thi Thu; Hoang, Tuan Anh; Ross, Hana; So, Anthony D.

2014-01-01

Illicit trade carries the potential to magnify existing tobacco-related health care costs through increased availability of untaxed and inexpensive cigarettes. What is known with respect to the magnitude of illicit trade for Vietnam is produced primarily by the industry, and methodologies are typically opaque. Independent assessment of the illicit cigarette trade in Vietnam is vital to tobacco control policy. This paper measures the magnitude of illicit cigarette trade for Vietnam between 199...

African dust carries microbes across the ocean: are they affecting human and ecosystem health?

Science.gov (United States)

Kellogg, Christina A.; Griffin, Dale W.

2003-01-01

Atmospheric transport of dust from northwest Africa to the western Atlantic Ocean region may be responsible for a number of environmental hazards, including the demise of Caribbean corals; red tides; amphibian diseases; increased occurrence of asthma in humans; and oxygen depletion (eutrophication) in estuaries. Studies of satellite images suggest that hundreds of millions of tons of dust are trans-ported annually at relatively low altitudes across the Atlantic Ocean to the Caribbean Sea and southeastern United States. The dust emanates from the expanding Sahara/Sahel desert region in Africa and carries a wide variety of bacteria and fungi. The U.S. Geological Survey, in collaboration with the NASA/Goddard Spaceflight Center, is conducting a study to identify microbes--bacteria, fungi, viruses--transported across the Atlantic in African soil dust. Each year, millions of tons of desert dust blow off the west African coast and ride the trade winds across the ocean, affecting the entire Caribbean basin, as well as the southeastern United States. Of the dust reaching the U.S., Florida receives about 50 percent, while the rest may range as far north as Maine or as far west as Colorado. The dust storms can be tracked by satellite and take about one week to cross the Atlantic.

Are trade-offs among species' ecological interactions scale dependent? A test using pitcher-plant inquiline species.

Science.gov (United States)

Kneitel, Jamie M

2012-01-01

Trade-offs among species' ecological interactions is a pervasive explanation for species coexistence. The traits associated with trade-offs are typically measured to mechanistically explain species coexistence at a single spatial scale. However, species potentially interact at multiple scales and this may be reflected in the traits among coexisting species. I quantified species' ecological traits associated with the trade-offs expected at both local (competitive ability and predator tolerance) and regional (competitive ability and colonization rate) community scales. The most common species (four protozoa and a rotifer) from the middle trophic level of a pitcher plant (Sarracenia purpurea) inquiline community were used to link species traits to previously observed patterns of species diversity and abundance. Traits associated with trade-offs (competitive ability, predator tolerance, and colonization rate) and other ecological traits (size, growth rate, and carrying capacity) were measured for each of the focal species. Traits were correlated with one another with a negative relationship indicative of a trade-off. Protozoan and rotifer species exhibited a negative relationship between competitive ability and predator tolerance, indicative of coexistence at the local community scale. There was no relationship between competitive ability and colonization rate. Size, growth rate, and carrying capacity were correlated with each other and the trade-off traits: Size was related to both competitive ability and predator tolerance, but growth rate and carrying capacity were correlated with predator tolerance. When partial correlations were conducted controlling for size, growth rate and carrying capacity, the trade-offs largely disappeared. These results imply that body size is the trait that provides the basis for ecological interactions and trade-offs. Altogether, this study showed that the examination of species' traits in the context of coexistence at different scales

Reduction of wind power induced reserve requirements by advanced shortest-term forecasts and prediction intervals

Energy Technology Data Exchange (ETDEWEB)

Dobschinski, Jan; Wessel, Arne; Lange, Bernhard; Bremen, Lueder von [Fraunhofer Institut fuer Windenergie und Energiesystemtechnik (IWES), Kassel (Germany)

2009-07-01

In electricity systems with large penetration of wind power, the limited predictability of the wind power generation leads to an increase in reserve and balancing requirements. At first the present study concentrates on the capability of dynamic day-ahead prediction intervals to reduce the wind power induced reserve and balancing requirements. Alternatively the reduction of large forecast errors of the German wind power generation by using advanced shortest-term predictions has been evaluated in a second approach. With focus on the allocation of minute reserve power the aim is to estimate the maximal remaining uncertainty after trading activities on the intraday market. Finally both approaches were used in a case study concerning the reserve requirements induced by the total German wind power expansion in 2007. (orig.)

Reliability/Cost Evaluation on Power System connected with Wind Power for the Reserve Estimation

DEFF Research Database (Denmark)

Lee, Go-Eun; Cha, Seung-Tae; Shin, Je-Seok

2012-01-01

Wind power is ideally a renewable energy with no fuel cost, but has a risk to reduce reliability of the whole system because of uncertainty of the output. If the reserve of the system is increased, the reliability of the system may be improved. However, the cost would be increased. Therefore...... the reserve needs to be estimated considering the trade-off between reliability and economic aspects. This paper suggests a methodology to estimate the appropriate reserve, when wind power is connected to the power system. As a case study, when wind power is connected to power system of Korea, the effects...

EU-Korea FTA and Its Impact on V4 Economies. A Comparative Analysis of Trade Sophistication and Intra-Industry Trade

Directory of Open Access Journals (Sweden)

Michalski Bartosz

2018-03-01

Full Text Available This paper investigates selected short- and mid-term effects in trade in goods between the Visegrad countries (V4: the Czech Republic, Hungary, Poland and the Slovak Republic and the Republic of Korea under the framework of the Free Trade Agreement between the European Union and the Republic of Korea. This Agreement is described in the “Trade for All” (2015: 9 strategy as the most ambitious trade deal ever implemented by the EU. The primary purpose of our analysis is to identify, compare, and evaluate the evolution of the technological sophistication of bilateral exports and imports. Another dimension of the paper concentrates on the developments within intra-industry trade. Moreover, these objectives are approached taking into account the context of the South Korean direct investment inflow to the V4. The evaluation of technological sophistication is based on UNCTAD’s methodology, while the intensity of intra-industry trade is measured by the GL-index and identification of its subcategories (horizontal and vertical trade. The analysis covers the timespan 2001–2015. The novelty of the paper lies in the fact that the study of South Korean-V4 trade relations has not so far been carried out from this perspective. Thus this paper investigates interesting phenomena identified in the trade between the Republic of Korea (ROK and V4 economies. The main findings imply an impact of South Korean direct investments on trade. This is represented by the trade deficit of the V4 with ROK and the structure of bilateral trade in terms of its technological sophistication. South Korean investments might also have had positive consequences for the evolution of IIT, particularly in the machinery sector. The political interpretation indicates that they may strengthen common threats associated with the middle-income trap, particularly the technological gap and the emphasis placed on lower costs of production.

Integration of 18 GW Wind Energy into the Energy Market. Practical Experiences in Germany. Experiences with large-scale integration of wind power into power systems

International Nuclear Information System (INIS)

Krauss, C.; Graeber, B.; Lange, M.; Focken, U.

2006-01-01

This work describes the integration of 18 GW of wind power into the German energy market. The focus lies on reporting practical experiences concerning the use of wind energy in Germany within the framework of the renewable energy act (EEG) and the immediate exchange of wind power between the four German grid control areas. Due to the EEG the demand for monitoring the current energy production of wind farms and for short-term predictions of wind power has significantly increased and opened a broader market for these services. In particular for trading on the intraday market ultra short term predictions in the time frame of 1 to 10 hours require different approaches than usual dayahead predictions because the large numerical meteorological models are not sufficiently optimized for very short time horizons. It is shown that for this range a combination of a statistical and a deterministic model leads to significant improvements and stable results as it unites the characteristics of the current wind power production with the synoptic-scale meteorological situation. The possible concepts of balancing the remaining differences between predicted and actual wind power generation are discussed. As wind power prediction errors and load forecasting errors are uncorrelated, benefits can arise from a combined balancing. Finally practical experiences with wind power fluctuations and large forecast errors are presented.

Wind energy potential analysis in Al-Fattaih-Darnah

Energy Technology Data Exchange (ETDEWEB)

Tjahjana, Dominicus Danardono Dwi Prija, E-mail: danar1405@gmail.com; Salem, Abdelkarim Ali, E-mail: keemsalem@gmail.com; Himawanto, Dwi Aries, E-mail: dwiarieshimawanto@gmail.com [University of Sebelas Maret, Jl. Ir. Sutami No. 36 A, Surakarta, Indonesia 57126 (Indonesia)

2016-03-29

In this paper the wind energy potential in Al-Fattaih-Darnah, Libya, had been studied. Wind energy is very attractive because it can provide a clean and renewable energy. Due mostly to the uncertainty caused by the chaotic characteristics of wind near the earth’s surface, wind energy characteristic need to be investigated carefully in order to get consistent power generation. This investigation was based on one year wind data measured in 2003. As a result of the analysis, wind speed profile and wind energy potential have been developed. The wind energy potential of the location is looked very promising to generate electricity. The annual wind speed of the site is 8.21 m/s and the wind speed carrying maximum energy is 7.97 m/s. The annual power density of the site is classified into class 3. The Polaris P50-500 wind turbine can produce 768.39 M Wh/year and has capacity factor of 17.54%.

Intercalibration and Cross-Correlation of Ace and Wind Solar Wind Data

Science.gov (United States)

2003-01-01

This report covers activities funded from October 1, 1998 through September 30, 2002. Two yearly status reports have been filed on this grant, and they are included as Appendix 1. The purpose of this grant was to compare ACE and Wind solar wind parameters when the two spacecraft were near to one another and then to use the intercalibrated parameters to carry out scientific investigations. In September, 2001 a request for a one-year, no-cost extension until September 30, 2002 was submitted and approved. The statement of work for that extension included adjustment of ACE densities below wind speeds of 350 km/s, a study of shock normal orientations using travel time delays between the two spacecraft, comparison of density jumps at shocks, and a study of temperature anisotropies and double streaming to see if such features evolved between the spacecraft.

Smoothing Control of Wind Farm Output by Using Kinetic Energy of Variable Speed Wind Power Generators

Science.gov (United States)

Sato, Daiki; Saitoh, Hiroumi

This paper proposes a new control method for reducing fluctuation of power system frequency through smoothing active power output of wind farm. The proposal is based on the modulation of rotaional kinetic energy of variable speed wind power generators through power converters between permanent magnet synchronous generators (PMSG) and transmission lines. In this paper, the proposed control is called Fluctuation Absorption by Flywheel Characteristics control (FAFC). The FAFC can be easily implemented by adding wind farm output signal to Maximum Power Point Tracking control signal through a feedback control loop. In order to verify the effectiveness of the FAFC control, a simulation study was carried out. In the study, it was assumed that the wind farm consisting of PMSG type wind power generator and induction machine type wind power generaotors is connected with a power sysem. The results of the study show that the FAFC control is a useful method for reducing the impacts of wind farm output fluctuation on system frequency without additional devices such as secondary battery.

Light Rotor: The 10-MW reference wind turbine

DEFF Research Database (Denmark)

Bak, Christian; Bitsche, Robert; Yde, Anders

2012-01-01

design show a rather well performing wind turbine both in terms of power and loads, but in the further work towards the final design the challenges in the control needs to be solved and the balance between power performance and loads and between structural performance and mass will be investigated......This paper describes the design of a rotor and a wind turbine for an artificial 10-MW wind turbine carried out in the Light Rotor project. The turbine called the Light Rotor 10-MW Reference Wind Turbine (LR10-MW RWT), is designed with existing methods and techniques and serves as a reference...... like the determination of the specific power and upscaling of the turbine. The design of Iteration #2 of the LR10-MW RWT is carried out in a sequence between aerodynamic rotor design, structural design and aero-servo-elastic design. Each of these topics is described. The results from the Iteration #2...

Oceanography. Centennial changes in North Pacific anoxia linked to tropical trade winds.

Science.gov (United States)

Deutsch, Curtis; Berelson, William; Thunell, Robert; Weber, Thomas; Tems, Caitlin; McManus, James; Crusius, John; Ito, Taka; Baumgartner, Timothy; Ferreira, Vicente; Mey, Jacob; van Geen, Alexander

2014-08-08

Climate warming is expected to reduce oxygen (O2) supply to the ocean and expand its oxygen minimum zones (OMZs). We reconstructed variations in the extent of North Pacific anoxia since 1850 using a geochemical proxy for denitrification (δ(15)N) from multiple sediment cores. Increasing δ(15)N since ~1990 records an expansion of anoxia, consistent with observed O2 trends. However, this was preceded by a longer declining δ(15)N trend that implies that the anoxic zone was shrinking for most of the 20th century. Both periods can be explained by changes in winds over the tropical Pacific that drive upwelling, biological productivity, and O2 demand within the OMZ. If equatorial Pacific winds resume their predicted weakening trend, the ocean's largest anoxic zone will contract despite a global O2 decline. Copyright © 2014, American Association for the Advancement of Science.

EFFECTS OF THE PENETRATION OF WIND POWER IN THE BRAZILIAN ELECTRICITY MARKET

Directory of Open Access Journals (Sweden)

Milton M. Herrera

2016-12-01

Full Text Available Climate variability has been the main driver for renewables in the Brazilian electricity market. This article analyzes the vulnerabilities of the dependence on hydropower in renewable energy production due to climate variation, as well as wind power penetration in Brazil, given a set of wind industry policies. Despite Brazilian renewable energy increase, the study shows the impact in energy supply in north region, due to the lack of transmission infrastructure. In Brazil, the potential trade-offs between renewables growth, and transmission infrastructure inconsistencies in terms of policy implementation are not yet well analyzed. Simulation results show the potential conflicts between energy policies aimed at increasing the wind power supply and boundaries in transmission infrastructure.

Effects of the penetration of wind power in the brazilian electricity market

Directory of Open Access Journals (Sweden)

Milton M. Herrera

2016-12-01

Full Text Available Climate variability has been the main driver for renewables in the Brazilian electricity market. This article analyzes the vulnerabilities of the dependence on hydropower in renewable energy production due to climate variation, as well as wind power penetration in Brazil, given a set of wind industry policies. Despite Brazilian renewable energy increase, the study shows the impact in energy supply in north region, due to the lack of transmission infrastructure. In Brazil, the potential trade-offs between renewables growth, and transmission infrastructure inconsistencies in terms of policy implementation are not yet well analyzed. Simulation results show the potential conflicts between energy policies aimed at increasing the wind power supply and boundaries in transmission infrastructure.

Financing wind plants, taking leasing into special account

International Nuclear Information System (INIS)

Veltrup, M.

1993-01-01

Leasing cannot be managed without a special sort of external financing of wind power plants. Specifically for wind energy, it was found from an investigation of less than a year that an intended erection of a wind power plant should be carried out in the months of September or October, so that the autumn and winter months rich in energy can be used. For the erection of small wind power plants, it was found that taking advantage of the Investment Cost Grant is more sensible than the Operating Cost Grant. (orig./HW) [de

Measuring Gas Concentration and Wind Intensity in a Turbulent Wind Tunnel with a Mobile Robot

Directory of Open Access Journals (Sweden)

Dani Martínez

2016-01-01

Full Text Available This paper presents the measurement of gas concentration and wind intensity performed with a mobile robot in a custom turbulent wind tunnel designed for experimentation with customizable wind and gas leak sources. This paper presents the representation in different information layers of the measurements obtained in the turbulent wind tunnel under different controlled environmental conditions in order to describe the plume of the gas and wind intensities inside the experimentation chamber. The information layers have been generated from the measurements gathered by individual onboard gas and wind sensors carried out by an autonomous mobile robot. On the one hand, the assumption was that the size and cost of these specialized sensors do not allow the creation of a net of sensors or other measurement alternatives based on the simultaneous use of several sensors, and on the other hand, the assumption is that the information layers created will have application on the development and test of automatic gas source location procedures based on reactive or nonreactive algorithms.

Wind Power: Growing with the Demand of Sustainable Development

Institute of Scientific and Technical Information of China (English)

Wang Chengxu; Li Wei

2009-01-01

@@ History review Looking back upon the human history, China is among the earliest countries which make use of wind energy. It started to use the wind energy to pump water for irrigation very long time ago. Since the establishment of the new China, pilot projects of wind energy generation have been carried out in many areas. In 1975, Tsinghua University and the Inner Mongolia Prairie Research Institute cooperated to develop wind turbines. They developed prototypes of 50/100-W off-grid micro wind turbines. Meanwhile, small wind turbines were also developed in other areas. The wind turbines produced at that time were all in small capacity and did not play important role in power industry.

Wind Energy Study and Energy Cost of Wind Electricity Generation in Nigeria: Past and Recent Results and a Case Study for South West Nigeria

Directory of Open Access Journals (Sweden)

Oluseyi O. Ajayi

2014-12-01

Full Text Available The study assessed the wind energy potential of ten selected sites in the south western region of Nigeria and carried out a cost benefit analysis of wind power generation at those sites. Twenty four years’ (1987 to 2010 wind speed data at 10 m height obtained from the Nigerian meteorological agency were employed to classify the sites wind profiles for electricity generation. The energy cost analysis of generating wind electricity from the sites was also carried out. The outcome showed that sites in Lagos and Oyo States were adequately suited for large scale generation with average wind speeds ranged between 2.9 and 5.8 m/s. Those from other sites may be suitable for small scale generation or as wind farms, with several small turbines connected together, to generate large enough wind power. The turbine matching results shows that turbines cut-in and rated wind speeds of between 2.0 and 3.0 m/s, and between 10 and 12.0 m/s respectively will be very suited to all the sites, particularly those in locations outside Lagos and Oyo States. The energy cost analysis shows that generation cost can be as low as 0.02 €/kWh and as high as 5.03/kWh, depending on the turbine model employed.

Use of wind energy in the Netherlands, part 2. The multi-annual programme for wind energy 1996-2000 TWIN-2

International Nuclear Information System (INIS)

Bouwmeester, H.; De Jong, I.

1996-08-01

The Dutch government would like to achieve a cleaner energy supply in the Netherlands. The target of the government is 10% saving of fossil fuels in 2020. How this can be realized is formulated in the Third White Paper on Energy Policy, published in December 1995. The use of renewable energy sources, including wind energy, plays an important part in this national policy. For the use of wind energy the government aims at a growth of the wind turbine capacity by an average of 100 MW per year, to be realized by installing wind turbines both on land and (in the longer term) offshore. This should result into a fuel saving of 33 PJ in 2007 and 45 PJ in 2020. To stimulate the use of wind energy Novem carried out the Use of Wind Energy in the Netherlands programme (TWIN) from 1991 to 1995. This programme has given a considerable impulse to the growth of wind turbine capacity in the Netherlands. Market parties have been able to complete around 250 MW up to 1996. The programme has unfortunately not resulted in an autonomous market, so the government has ordered the implementation of the TWIN-2 follow-up programme. This follow-up programme runs from 1996 to 2000 and provides a framework for the operations which Novem will be carrying out over this period in the field of wind energy. In this brochure the main elements of the programme are outlined. Also a state-of-the-art is given since the end of 1995, as well as an overview of developments in the wind energy market, and the mission, aim and targets of the TWIN-2 programme. 12 refs

Concurrent Aeroservoelastic Design and Optimization of Wind Turbines

DEFF Research Database (Denmark)

Tibaldi, Carlo

This work develops and investigates methods to integrate controllers in the wind turbine design process and to perform wind turbine optimization. These techniques can exploit the synergy between wind turbine components and generate new design solutions. Two frameworks to perform wind turbine...... optimization design are presented. These tools handle workflows to model a wind turbine and to evaluate loads and performances under specific conditions. Three approaches to evaluate loads are proposed and integrated in the optimization codes. The first method is based on time domain simulations, the second...... simulations, allows the selection of any controller parameter. The methods to evaluate loads and the pole-placement technique are then employed to carry out wind turbine optimization design from an aeroservoelastic prospective. Several analysis of the NREL 5 MW Reference Wind Turbine and the DTU 10 MW...

China's WTO commitments in agriculture and impacts of potential OECD agricultural trade liberalizations

DEFF Research Database (Denmark)

Yu, Wusheng; Frandsen, Søren E.

2005-01-01

general equilibrium simulation results show that China’s WTO commitments will lead to increased agricultural imports and slightly declined outputs in China. The resulting efficiency gains will be negated by terms-of-trade losses, leading to quantitatively small welfare impacts. Furthermore, sectoral...... results depend critically on correctly representing the more complex policy measures, such as the tariff rate quotas. The negative output effects on Chinese agriculture can be alleviated/reversed if the rich OECD countries commit to reform their agriculture policies. The present paper concludes that trade...... liberalization should be carried out in both developing and developed countries. Reforming the latter will be particularly helpful in easing the problems facing those developing countries that are carrying out ambitious trade reforms....

A study of wind hydrogen production of systems for Malaysia

International Nuclear Information System (INIS)

Ibrahim, M.Z.; Kamaruzzaman Sopian; Wan Ramli Wan Daud; Othman, M.Y.; Baharuddin Yatim; Veziroglu, T.N.

2006-01-01

Recently, Malaysia is looking into the potential of using hydrogen as future fuel. By recognizing the potential of hydrogen fuel, the government had channeled a big amount of money in funds to related organizations to embark on hydrogen research and development programmed. The availability of indigenous renewable resources, high trade opportunities, excellent research capabilities and current progress in hydrogen research at the university are some major advantages for the country to attract government and industry investment in hydrogen. It is envisaged that overall energy demand in Malaysia as stated in the Eighth Malaysia Plan (EMP) report will increase by about 7.8 percent per annum in this decade at the present economic growth. Considering the vast potential inherent in renewable energy (RE), it could be a significant contributor to the national energy supply. Malaysia had been blessed with abundant and varied resources of energy, nevertheless, concerted efforts should be undertaken to ensure that the development of energy resources would continue to contribute to the nation's economic expansion. In this regard, an initial study has been carried out to see the available potential of wind energy towards the hydrogen production, that could be utilized in various applications particularly in Malaysian climate condition via a computer simulation (HYDROGEMS), which built for TRNSYS (a transient system simulation program) version 15. The system simulated in this study consist of one unit (1 kW) wind turbine, an electrolyze (1 kW), a hydrogen (H 2 ) storage tank, and a power conditioning system. A month hourly data of highest wind speed is obtained from the local weather station that is at Kuala Terengganu Air Port located at 5''o 23'' latitude (N) and 103''o 06'' Longitude (E). The results show, wind energy in Malaysian Climate has a potential to generate hydrogen with the minimum rate approximately 9 m 3 /hr and storage capacity of 60 Nm 3 , State of Charge (SOC

Short-term strategies for Dutch wind power producers to reduce imbalance costs

International Nuclear Information System (INIS)

Chaves-Ávila, José Pablo; Hakvoort, Rudi A.; Ramos, Andrés

2013-01-01

The paper assesses bidding strategies for a wind power producer in the Netherlands. To this end, a three-stage stochastic optimization framework is used, maximizing wind power producer's profit using the day-ahead and cross-border intraday market, taking into account available interconnection capacity. Results show that the wind power producer can increase its profits by trading on the intraday market and – under certain imbalance prices – by intentionally creating imbalances. It has been considered uncertainties about prices, power forecast and interconnection capacity at the day-ahead and intraday timeframes. - Highlights: ► A cross-border bidding strategy model for wind power producers has been developed. ► The model was applied to a real case study of a Dutch offshore wind power producer. ► Under certain imbalance prices, it is not profitable to deliver all possible power. ► Intraday markets give the possibility to reduce imbalance costs. ► Integration of intraday markets will increase liquidity.

Ecological restoration and recovery in the wind-blown sand hazard areas of northern China: relationship between soil water and carrying capacity for vegetation in the Tengger Desert.

Science.gov (United States)

Li, XingRong; Zhang, ZhiShan; Tan, HuiJuan; Gao, YanHong; Liu, LiChao; Wang, XingPing

2014-05-01

The main prevention and control area for wind-blown sand hazards in northern China is about 320000 km(2) in size and includes sandlands to the east of the Helan Mountain and sandy deserts and desert-steppe transitional regions to the west of the Helan Mountain. Vegetation recovery and restoration is an important and effective approach for constraining wind-blown sand hazards in these areas. After more than 50 years of long-term ecological studies in the Shapotou region of the Tengger Desert, we found that revegetation changed the hydrological processes of the original sand dune system through the utilization and space-time redistribution of soil water. The spatiotemporal dynamics of soil water was significantly related to the dynamics of the replanted vegetation for a given regional precipitation condition. The long-term changes in hydrological processes in desert areas also drive replanted vegetation succession. The soil water carrying capacity of vegetation and the model for sand fixation by revegetation in aeolian desert areas where precipitation levels are less than 200 mm are also discussed.

Northerly surface winds over the eastern North Pacific Ocean in spring and summer

Science.gov (United States)

Taylor, S.V.; Cayan, D.R.; Graham, N.E.; Georgakakos, K.P.

2008-01-01

Persistent spring and summer northerly surface winds are the defining climatological feature of the western coast of North America, especially south of the Oregon coast. Northerly surface winds are important for upwelling and a vast array of other biological, oceanic, and atmospheric processes. Intermittence in northerly coastal surface wind is characterized and wind events are quantitatively defined using coastal buoy data south of Cape Mendocino on the northern California coast. The defined wind events are then used as a basis for composites in order to explain the spatial evolution of various atmospheric and oceanic processes. Wind events involve large-scale changes in the three-dimensional atmospheric circulation including the eastern North Pacific subtropical anticyclone and southeast trade winds. Composites of QSCAT satellite scatterometer wind estimates from 1999 to 2005 based on a single coastal buoy indicate that wind events typically last 72-96 h and result in anomalies in surface wind and Ekman pumping that extend over 1000 kin from the west coast of North America. It may be useful to consider ocean circulation and dependent ecosystem dynamics and the distribution of temperature, moisture, and aerosols in the atmospheric boundary layer in the context of wind events defined herein. Copyright 2008 by the American Geophysical Union.

Attitudes towards wind power development in Denmark

DEFF Research Database (Denmark)

Ladenburg, Jacob

The present paper analyses the attitudes towards existing and future land-based turbines and off-shore wind farms. The analysis is carried out using a probit model to elicit systematic characteristics determining the attitude of the population. The analyses show that off-shore development...... is preferred to land based development, which indicates that the wind power development should be taken off-shore. But, the results also point out that the land-based opportunities for wind power development are not exhausted. On a more detailed level, the results denote that the attitude towards both land...... based and off-shore wind power vary with age of the respondents and experience with wind turbines. Younger respondents are more positive towards wind power than older respondents, pointing towards an increase in acceptance in the future. The attitude was also found to covariate negatively...

Reliability of Wind Speed Data from Satellite Altimeter to Support Wind Turbine Energy

Science.gov (United States)

Uti, M. N.; Din, A. H. M.; Omar, A. H.

2017-10-01

Satellite altimeter has proven itself to be one of the important tool to provide good quality information in oceanographic study. Nowadays, most countries in the world have begun in implementation the wind energy as one of their renewable energy for electric power generation. Many wind speed studies conducted in Malaysia using conventional method and scientific technique such as anemometer and volunteer observing ships (VOS) in order to obtain the wind speed data to support the development of renewable energy. However, there are some limitations regarding to this conventional method such as less coverage for both spatial and temporal and less continuity in data sharing by VOS members. Thus, the aim of this research is to determine the reliability of wind speed data by using multi-mission satellite altimeter to support wind energy potential in Malaysia seas. Therefore, the wind speed data are derived from nine types of satellite altimeter starting from year 1993 until 2016. Then, to validate the reliability of wind speed data from satellite altimeter, a comparison of wind speed data form ground-truth buoy that located at Sabah and Sarawak is conducted. The validation is carried out in terms of the correlation, the root mean square error (RMSE) calculation and satellite track analysis. As a result, both techniques showing a good correlation with value positive 0.7976 and 0.6148 for point located at Sabah and Sarawak Sea, respectively. It can be concluded that a step towards the reliability of wind speed data by using multi-mission satellite altimeter can be achieved to support renewable energy.

The Effect of Foreign Trade Policy Transparency on Integration of Ukraine in the World Economy

Directory of Open Access Journals (Sweden)

Yakovchenko Victoria S.

2018-02-01

Full Text Available The article is concerned with the interdependence between dynamics of the international trade and economic relations development and the existing level of foreign trade policy transparency in accordance with the provisions of the WTO Trade Facilitation Agreement. The effect of observance of transparency principle in foreign trade policy on forming the transaction costs in foreign trade is analyzed. A comparative analysis of the influence of import duties and transaction costs on the formation of Ukraine’s foreign trade barriers is carried out. Prospects of the national export-import activity development under increasing transparency of foreign trade policy of Ukraine and other world countries are determined.

International trade of CITES listed bird species in China.

Science.gov (United States)

Li, Linlin; Jiang, Zhigang

2014-01-01

Commercial trade of wild birds may devastate wild bird populations. Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) controls the trade of wild species listed in its appendices to avoid these species being threatened by international trade. China used to be one of the major trading countries with significant bird trade with foreign countries; on the other hand, China is a country with unique avian fauna, many Important Bird Areas and critically endangered bird species. What is the role of the country in world wild bird trade? What kind of insights can we extract from trade records for improving future management of wild bird trade in the country? We retrieved and analyzed international trade records of the CITES listed bird species of China from 1981 to 2010 from the CITES Trade Database maintained by United Nations Environment Program and World Conservation Monitoring Centre (UNEP-WCMC). We found that: (1) International trade of live birds in China peaked during the late 1990s, then decreased to the level before the surge of trade in a few years, the trade dynamics of wild birds may be affected by governmental policy and the outbreak of avian influenza during the period. (2) Most frequently traded CITES Appendix listed birds in China were parrots, most of which were exotic species to the country. (3) Birds were mainly traded for commercial purpose. Exotic birds in trade were mainly captive-bred while the most Chinese birds traded internationally were captured from the wild. Since many bird species in international trade are threatened to extinction, China should take stricter measures on importing of wild-captured birds and should collaborate with the countries of original in the international bird trade to avoid unsustainable harvesting of wild birds. It is urgent for China to carry out population surveys on those domestic bird species once in significant international trade and to make better conservation decisions based on

International Trade of CITES Listed Bird Species in China

Science.gov (United States)

Li, Linlin; Jiang, Zhigang

2014-01-01

Commercial trade of wild birds may devastate wild bird populations. Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) controls the trade of wild species listed in its appendices to avoid these species being threatened by international trade. China used to be one of the major trading countries with significant bird trade with foreign countries; on the other hand, China is a country with unique avian fauna, many Important Bird Areas and critically endangered bird species. What is the role of the country in world wild bird trade? What kind of insights can we extract from trade records for improving future management of wild bird trade in the country? We retrieved and analyzed international trade records of the CITES listed bird species of China from 1981 to 2010 from the CITES Trade Database maintained by United Nations Environment Program and World Conservation Monitoring Centre (UNEP-WCMC). We found that: (1) International trade of live birds in China peaked during the late 1990s, then decreased to the level before the surge of trade in a few years, the trade dynamics of wild birds may be affected by governmental policy and the outbreak of avian influenza during the period. (2) Most frequently traded CITES Appendix listed birds in China were parrots, most of which were exotic species to the country. (3) Birds were mainly traded for commercial purpose. Exotic birds in trade were mainly captive-bred while the most Chinese birds traded internationally were captured from the wild. Since many bird species in international trade are threatened to extinction, China should take stricter measures on importing of wild-captured birds and should collaborate with the countries of original in the international bird trade to avoid unsustainable harvesting of wild birds. It is urgent for China to carry out population surveys on those domestic bird species once in significant international trade and to make better conservation decisions based on

Mesoscale modeling of smoke transport over the Southeast Asian Maritime Continent: Interplay of sea breeze, trade wind, typhoon, and topography

Science.gov (United States)

Wang, Jun; Ge, Cui; Yang, Zhifeng; Hyer, Edward J.; Reid, Jeffrey S.; Chew, Boon-Ning; Mahmud, Mastura; Zhang, Yongxin; Zhang, Meigen

2013-03-01

The online-coupled Weather Research and Forecasting model with Chemistry (WRFchem) is used to simulate the transport of smoke particles over the Southeast Asian Maritime Continent during September-October 2006. In this period, dry conditions associated with the moderate El Niño event caused the largest regional biomass burning outbreak since 1997. Smoke emission in WRFchem is specified according to the Fire Locating and Modeling of Burning Emissions (FLAMBE) database derived from Moderate Resolution Imaging Spectroradiometer (MODIS) fire products. The modeled smoke transport pathway is found to be consistent with the MODIS true color images and measured mass concentration of surface PM10 (particulate matter with diameter less than 10 μm). The interplay of sea/land breezes, typhoons and storms over the subtropical western Pacific Ocean, trade winds, and topographic effects, can be clearly seen in the model simulation. The most severe smoke events in 1-5 October 2006 are found to be associated with the meteorological responses to the typhoon Xangsane (#18) over the western subtropical Pacific Ocean, which moved smoke from Sumatra eastward in the lower troposphere (below 700 hPa), forming smoke layers mixed with and above the boundary layer clouds over Borneo. In contrast, the second largest week-long smoke transport event of 15-18 October 2006 was associated with the seasonal monsoonal transition period, during which smoke plumes were wide spread over the 5°S-5°N zone as a result of (a) the near surface divergence coupled with the 700 hPa bifurcation of wind (flowing both to the west and to the east), and (b) the near-surface southeasterly and easterly winds along the equator transporting smoke from Borneo to Sumatra and Peninsular Malaysia. Analysis of data from the Cloud-Aerosol Lidar with Orthogonal Polarisation (CALIOP) shows that smoke particles in October 2006 were primarily located within 3.5 km above the surface. Smoke particles contributed roughly half

World trade in forest products and wood fuel

International Nuclear Information System (INIS)

Hillring, Bengt

2006-01-01

Wood fuel is a strategic resource for future energy supply and is usually utilised locally. Traditional use of wood fuel and other bioenergy has a share of 10-15% energy supply, used mainly for the household sector. The utilisation for industrial purposes is much smaller but is a strategic resource in the effort to fulfil the Kyoto agreement to replace fossil fuels and to mitigate greenhouse gas emissions. Many industrialised countries already use a significant share of biofuels in their energy supply e.g. Nordic countries while others like some other European Union countries are planning to increase their use. Production and use of biofuels need to be carried out sustainable. Official statistics do not report trade in such detail that international trade in different biomass types can be fully identified. However, FAO and European Forestry Institute are important sources. In some countries, there is a growing interest in the international trade, because the trade can provide biofuels at lower prices, larger quantities and better quality than domestic alternatives. The first signs of an international market price for wood fuel are indicated in Europe. For the future both the use and the trade of wood fuel is expected to increase. Analyses for trade in charcoal, wood chips, fuel wood and wood residues made in this report identify 'hot' trade spots in Europe, in south East Asia and in North America

Regional hydrogen roadmap. Project development framework for the Sahara Wind Project

Energy Technology Data Exchange (ETDEWEB)

Benhamou, Khalid [Sahara Wind Inc., Rabat (Morocco); Arbaoui, Abdelaziz [Ecole National Superieure des Arts et Metiers ENSAM Meknes (Morocco); Loudiyi, Khalid [Al Akhawayn Univ. (Morocco); Ould Mustapha, Sidi Mohamed [Nouakchott Univ. (Mauritania). Faculte des Sciences et Techniques

2010-07-01

The trade winds that blow along the Atlantic coast from Morocco to Senegal represent one of the the largest and most productive wind potentials available on earth. Because of the erratic nature of winds however, wind electricity cannot be integrated locally on any significant scale, unless mechanisms are developed for storing these intermittent renewable energies. Developing distributed wind energy solutions feeding into smaller electricity markets are essential for solving energy access issues and enabling the development of a local, viable renewable energy industry. These may be critical to address the region's economic challenges currently under pressure from Sub-Saharan migrant populations. Windelectrolysis for the production of hydrogen can be used in grid stabilization, as power storage, fuel or chemical feedstock in specific industries. The objective of the NATO SfP 'Sahara Trade Winds to Hydrogen' project is to support the region's universities through an applied research framework in partnership with industries where electrolysis applications are relevant. By powering two university campuses in Morocco and Mauritania with small grid connected wind turbines and 30 kW electrolyzers generating hydrogen for power back-up as part of ''green campus concepts'' we demonstrated that wind-electrolysis for the production of hydrogen could absorb larger quantities of cheap generated wind electricity in order to maximize renewable energy uptakes within the regions weaker grid infrastructures. Creating synergies with local industries to tap into a widely available renewable energy source opens new possibilities for end users such as utilities or mining industries when processing raw minerals, whose exports generates key incomes in regions most exposed to desertification and climate change issue. Initiated by Sahara Wind Inc. a company from the private sector, along with the Al Akhawayn University, the Ecole Nationale Superieure

Urban Wind Energy - State of the Art 2009

DEFF Research Database (Denmark)

Beller, Christina

Wind energy in urban areas is a new area and a rather blank page concerning design criteria, aesthetics, concepts, minimizing costs etc. Even though the potential energy in the flow is much higher on the country side or off-shore, the erection of wind turbines in urban areas is carried out and also...

Trading volume and the number of trades

OpenAIRE

Marwan Izzeldin

2007-01-01

Trading volume and the number of trades are both used as proxies for market activity, with disagreement as to which is the better proxy for market activity. This paper investigates this issue using high frequency data for Cisco and Intel in 1997. A number of econometric methods are used, including GARCH augmented with lagged trading volume and number of trades, tests based on moment restrictions, regression analysis of volatility on volume and trades, normality of returns when standardized by...

Wind farm layout optimization in complex terrain with CFD wakes: Paper presented at EWEA 2015, Europe's Premier Wind Energy Event, 17 - 20 November 2015, Paris, France

OpenAIRE

Schmidt, J.; Stoevesandt, B.

2015-01-01

For a complex terrain site in Bahia, Brazil, 28 CFDRANS simulations were carried out, representing the relevant states of a wind rose with three degrees resolution. The resulting wind fields provide the background wind for the layout optimization of a wind farm with 64 wind turbines based on the AEP. The underlying wake model was deduced from CFD-RANS simulation results of an isolated actuator disk. We find that a hybrid optimization algorithm that combines genetic and gradient-based optimize...

Danish wind power in Brazil. Part 1. The future of wind power in Brazil - market analysis

Energy Technology Data Exchange (ETDEWEB)

Husted Rich, N

1996-04-01

More than 95% of total energy produced in Brazil comes from highly efficient hydroelectric power plants but, faced with a serious shortage of energy after the year 2000, the country is now considering wind energy as one of the basic alternatives for energy supply. It is suggested that biomass, wind energy and biogas may be included in a future supply policy for the north-east region of the land. The structure of, the privatisation, legislation and the tariff system within the Brazilian power sector are described in addition to the present situation regarding wind energy in the country, including current and coming projects in this field, the excellent wind conditions in Northeastern Brazil and investment possibilities. The political activities in this field of the Danish Folkecenter for Renewable Energy are noted and future developments in Brazil are discussed. It is concluded that there are good prospects for Danish windmill technology on the Brazilian market. Wind measurement programs are presently being carried out in various areas of the country, though a number of impediments to the development of wind energy in Brazil remain. (AB)

Wind Turbines Adaptation to the Variability of the Wind Field

Science.gov (United States)

Ulianov, Yuriy; Martynenko, Gennadii; Misaylov, Vitaliy; Soliannikova, Iuliia

2010-05-01

including combined RF-acoustic antenna installed coaxially with the gondola of the wind power turbine. The work of the technique is synchronized with rotation of blades to eliminate their shielding action. Dangerous in terms of dynamic strength is the wind load pulse, the rise time which is comparable with the period of the natural frequency of the wind turbine elements (blade, tower, rotor, etc.). The amplitude decay of resonant vibrations at critical values of the speed of rotation can be realized through the use of mechanical elastic supports with nonlinear artificial dampers. They have a high coefficient of resistance, but may cause self-excited oscillations. We propose the way to deal with raised vibration of wind turbine elements at the expense of short-term increase of damping in the range of critical rotary axis speeds or during impulsive effects of wind loadings (wind gusts). This is possible through the use of non-linear electromagnetic dampers or active magnetic bearings. Their feature is the possibility of varying the mechanical stiffness and damping properties by changing the electrical parameters of electromagnets. The controlling of these parameters is carried out by the control system (CS) with the information feedback on the spatial-temporal structure of the wind field obtained from IRASS. In the composition of the CS can also be included the rotational speed sensor of the WPT rotor. This approach to the adaptation of wind turbines will allow to reduce vibration and to perform early compensation of the load on their components, which arise under the wind gusts. In addition, corrections about the wind field obtained with IRASS, would increase the mean power of WPT.

Regional Trade Agreement and Agricultural Trade in East African ...

African Journals Online (AJOL)

Intra-EAC trade is very low, that is, at 9 per cent of the total regional trade, but it is on upward trend. Agricultural trade accounts for over 40 per cent of the intra-EAC trade. This study investigated the effect of EAC regional trade agreement on the regions agricultural trade by analyzing the degree of trade creation and ...

Trade creation and trade diversion in the Canada - United States Free Trade Agreement

OpenAIRE

Kimberly A. Clausing

2001-01-01

In this paper the changes in trade patterns introduced by the Canada-United States Free Trade Agreement are examined. Variation in the extent of tariff liberalization under the agreement is used to identify the impact of tariff liberalization on the growth of trade both with member countries and non-member countries. Data at the commodity level are used, and the results indicate that the Canada-United States Free Trade Agreement had substantial trade creation effects, with little evidence of ...

Decision Support Tools for Electricity Retailers, Wind Power and CHP Plants Using Probabilistic Forecasts

DEFF Research Database (Denmark)

Zugno, Marco; Morales González, Juan Miguel; Madsen, Henrik

2015-01-01

: trading for a price-maker wind power producer, management of heat and power systems, operation for retailers in a dynamic-price market. A selection of results shows the viability and appropriateness of the presented stochastic optimization approaches for managing energy systems under uncertainty....

The Gravity Model Approach: An Application on the Eco Was Trading Bloc

Directory of Open Access Journals (Sweden)

Luqman Afolabi O.

2016-04-01

Full Text Available This study aims to examine bilateral trade flows across ECOWAS-15 nations with the use of a panel and cross section for the period of 1981-2013. The methodology carried out to achieve this objective involves the use of various techniques of estimation for the gravity model (Static and dynamic. More specifically, this study aims to investigate the formational impact of regional trade integration agreements on trade flows within a group of countries using the same currencies and ECOWAS at large. The main use of regional variables into gravity models is intended to determine whether RTAs lead to trade creation, or diversion. The results show the presence of a strong relationship among the factors of both RIAs and trade flows.

Wind-Tunnel Investigation of Wind Loads on a Post-Panamax Container Ship as a Function of the Container Configuration on Deck

DEFF Research Database (Denmark)

Andersen, Ingrid Marie Vincent

2012-01-01

An investigation of the wind forces acting on a 9,000+ TEU container ship has been carried out through a series of wind tunnel tests. It was investigated how the wind forces depend on the container configuration on the deck using a 1:450 scale model and a series of appropriate container...... are presented as nondimensional coefficients. It is concluded, that the measured forces and moment depend on the container configuration on deck, and the results may provide a general idea of how the magnitude of the wind forces is affected by a given container stacking configuration on a similar container ship....

Trade Policy

OpenAIRE

Murray Gibbs

2007-01-01

In an otherwise insightful and thoughtful article, Sebastian Pfotenhauer (Trade Policy Is Science Policy,” Issues, Fall 2013) might better have entitled his contribution “Trade Policy Needs to Be Reconciled with Science Policy.” The North American Free Trade Agreement (NAFTA) and the agreements administered by the World Trade Organization, particularly the General Agreement on Tariffs and Trade (GATT) and the Technical Barriers to Trade (TBT), were adopted to promote international trade and i...

International provision of trade services, trade, and fragmentation

OpenAIRE

Deardorff, Alan V.

2001-01-01

The author examines the special role that trade liberalization in services industries can play in stimulating trade in both services, and goods. International trade in goods requires inputs from such trade services as transportation, insurance, and finance, for example. Restrictions on services across borders, and within foreign countries add costs, and barriers to international trade. Lib...

Ripple Field AC Losses in 10-MW Wind Turbine Generators With a MgB2 Superconducting Field Winding

DEFF Research Database (Denmark)

Liu, Dong; Polinder, Henk; Magnusson, Niklas

2016-01-01

Superconducting (SC) synchronous generators are proposed as a promising candidate for 10-20-MW direct-drive wind turbines because they can have low weights and small sizes. A common way of designing an SC machine is to use SC wires with high current-carrying capability in the dc field winding...... and the ac armature winding is made with copper conductors. In such generators, the dc field winding is exposed to ac magnetic field ripples due to space harmonics from the armature. In generator design phases, the ac loss caused by these ripple fields needs to be evaluated to avoid local overheating...... and an excessive cooling budget. To determine the applicability of different design solutions in terms of ac losses, this paper estimates the ac loss level of 10-MW wind generator designs employing a MgB2 SC field winding. The effects on ac losses are compared between nonmagnetic and ferromagnetic teeth...

Observation of wind field over heterogeneous terrain by the French-German airborne Doppler lidar WIND

Science.gov (United States)

Dabas, A.; Werner, C.; Delville, P.; Reitebuch, O.; Drobinski, P.; Cousin, F.

2003-04-01

In summer 2001, the French-German airborne Doppler lidar WIND participated to field campaign ESCOMPTE. ESCOMPTE was carried out in the region of Marseille along the Mediterranean coast of France. It was dedicated to the observation of heavy pollution events in this industrialized, densely populated region of nearly 4 million inhabitants. The aim was to gather a data base as comprehensive as possible on several pollution events and use them to check the ability of several regional forecast models to predict such events. The specific mission devoted to WIND was the characterization at mesoscale of the wind field and the topography of the planetary boundary layer. Both are complex around Marseille due the heterogeneity of the surface with a transition sea/land to the south, the fore-Alps to the North, the Rhône valley to the North-West etc... Seven, 3-hr flights were carried out and gave excellent results. In 2002, first comparisons were made with mesoscale models. They will be shown during the presentation. They are good examples of the usefulness of airborne Doppler lidar for validating and improving atmospheric model simulations.

Wind tunnel study of a vertical axis wind turbine in a turbulent boundary layer flow

Science.gov (United States)

Rolin, Vincent; Porté-Agel, Fernando

2015-04-01

Vertical axis wind turbines (VAWTs) are in a relatively infant state of development when compared to their cousins the horizontal axis wind turbines. Very few studies have been carried out to characterize the wake flow behind VAWTs, and virtually none to observe the influence of the atmospheric boundary layer. Here we present results from an experiment carried out at the EPFL-WIRE boundary-layer wind tunnel and designed to study the interaction between a turbulent boundary layer flow and a VAWT. Specifically we use stereoscopic particle image velocimetry to observe and quantify the influence of the boundary layer flow on the wake generated by a VAWT, as well as the effect the VAWT has on the boundary layer flow profile downstream. We find that the wake behind the VAWT is strongly asymmetric, due to the varying aerodynamic forces on the blades as they change their position around the rotor. We also find that the wake adds strong turbulence levels to the flow, particularly on the periphery of the wake where vortices and strong velocity gradients are present. The boundary layer is also shown to cause greater momentum to be entrained downwards rather than upwards into the wake.

Metal-enhanced galactic winds. I

International Nuclear Information System (INIS)

Vader, J.P.

1986-01-01

Supernova-driven gas loss during the early evolution of elliptical galaxies is considered as a possible explanation for the correlations among the observed chemical and structural properties of these systems. Mass loss from systems with a chemically homogeneous interstellar medium does not work. It is pointed out that supernova-driven winds are in fact metal-enhanced with respect to the star-forming gas because the metal production of any supernova that drives the wind is directly flushed out of the galaxy. The fraction of the total metal production lost in the wind is thus at least as large as the fraction epsilon(z) of supernovae that power the wind, independent of the total mass loss. As a corollary, the yield of heavy elements that are recycled in the galaxy is reduced by a factor 1 - epsilon(z). Metal-enhanced galactic winds, which can carry away a large fraction of the metal production in spite of a moderate total mass loss, offer a promising explanation for the low metallicities of dwarf elliptical galaxies. 62 references

The Feasibility Study on Thermal Loading Control of Wind Power Converters with a Flexible Switching Frequency

DEFF Research Database (Denmark)

Qin, Zian; Wang, Huai; Blaabjerg, Frede

2015-01-01

Thermal loading of wind power converters is critical to their reliability performance. Especially for IGBT modules applied in a converter, both of the mean value and variation of the junction temperature have significant impact on the lifetime. Besides other strategies to reduce the thermal loadi...... the temperature fluctuations due to wind speed variations. The trade-off between the reduced amplitude of temperature fluctuations and the additional power losses that may be introduced is quantitatively studied....

Uncertainty Quantification of the Real-Time Reserves for Offshore Wind Power Plants

DEFF Research Database (Denmark)

Göçmen, Tuhfe; Giebel, Gregor; Réthoré, Pierre-Elouan

In order to retain the system stability, the wind power plants are required to provide ancillary services. One of those services is reserve power. Here in this study, we focus on the real-time reserves which can be traded in the balancing markets and are currently used for compensation under...... mandatory downregulation stated by the transmission system operators (TSOs). The PossPOW project (Possible Power of down-regulated Offshore Wind power plants) developed a real-time power curve of available power for offshore wind farms for use during down-regulation. The follow-up Concert project......(control and uncertainties in real-time power curves of offshore wind power plants) aims to quantify and finally reduce the uncertainty in reserve power, bringing the PossPOW algorithm and the state of the art forecasting methods together. The experiments designed to test the available power estimated by the Poss...

A real-scale helical coil winding trial of the Large Helical Device

International Nuclear Information System (INIS)

Senba, T.; Yamamoto, T.; Tamaki, T.; Asano, K.; Suzuki, S.; Yamauchi, T.; Uchida, K.; Nakanishi, K.; Yamagiwa, T.; Suzuki, S.; Miyoshi, R.; Sasa, H.; Watanabe, S.; Tatemura, M.; Hatada, N.; Yamaguchi, S.; Imagawa, S.; Yanagi, N.; Satow, T.; Yamamoto, J.; Motojima, O.

1995-01-01

A real-scale helical coil winding trial of the Large Helical Device (LHD) has been conducted for a study of coil winding configuration and winding methods and for exhibiting the state of the art. It includes construction and test run of a specifically designed winding machine and development of various manufacturing methods for accurate coil winding. It has been carried out in Hitachi Works before in situ winding, and has provided much needed engineering data for construction of the LHD. (orig.)

Siting guidelines for utility application of wind turbines. Final report

Energy Technology Data Exchange (ETDEWEB)

Pennell, W.T.

1983-01-01

Utility-oriented guidelines are described for identifying viable sites for wind turbines. Topics and procedures are also discussed that are important in carrying out a wind turbine siting program. These topics include: a description of the Department of Energy wind resource atlases; procedures for predicting wind turbine performance at potential sites; methods for analyzing wind turbine economics; procedures for estimating installation and maintenance costs; methods for anlayzing the distribution of wind resources over an area; and instrumentation for documenting wind behavior at potential sites. The procedure described is applicable to small and large utilities. Although the procedure was developed as a site-selection tool, it can also be used by a utility who wishes to estimate the potential for wind turbine penetration into its future generation mix.

Macroeconomic context of the trade branch development and position in Czech Republic

Directory of Open Access Journals (Sweden)

Marek Záboj

2006-01-01

Full Text Available The paper deals with analysis of the macroeconomic associations of trade development and its position in Czech Republic as one of the national economy branch. The development of main macroeconomic indicators for period of 1998–2004 is completed and then it follows up with progress of the trade structures and trade chains. In that frame the given indicators (number of registered and active business units in trade, turnover and number of employees are monitoring according to Economic Subjects Register (provided by Czech Statistical Office and Classification of Economic Activities in the European Union. On the basis of research of consulting and research institutions the overview and turnover comparison for TOP 10 trade firms for period of 2000–2004 is carried out. Inseparable part of the paper is analysis of the Czech Republic foreign trade results. In this field the export, import and trade balance are discussing on the one hand in general and on the other hand in territorial and commodity structures.

Shifting towards offshore wind energy—Recent activity and future development

International Nuclear Information System (INIS)

Kaldellis, J.K.; Kapsali, M.

2013-01-01

To date, most of the existing wind farms have been built on-land but during the last few years many countries have also invested in offshore applications. The shift towards offshore wind project developments has mainly been driven by European energy policies, especially in north-west countries. In offshore sites the winds are stronger and steadier than on-land, making wind farms more productive with higher capacity factors. On the other hand, although offshore wind energy is not in its infancy period, most of the costs associated with its development are still much higher from onshore counterparts; however some recent technological progress may have the potential to narrow this gap in the years to come. In the present work, an overview of the activity noted in the field of offshore wind energy is carried out, with emphasis being given on the current status and future trends of the technology employed, examining at the same time energy production and availability issues as well as economic considerations. - Highlights: ► An overview of the activity noted in the field of offshore wind energy is carried out. ► Emphasis is given on the current status and future trends of the technology. ► Wind energy production and availability issues are discussed. ► Economic issues such as investment and energy production costs are also analysed.

Trade-off between growth and immune function : a meta-analysis of selection experiments

NARCIS (Netherlands)

van der Most, Peter; de Jong, Berber; Parmentier, Henk K.; Verhulst, Simon

P>1. Evidence suggests that developing and maintaining an effective immune system may be costly and that an organism has to make a trade-off between immune function and other fitness-enhancing traits. To test for a trade-off between growth and immune function we carried out a meta-analysis of data

A seasonal copula mixture for hedging the clean spark spread with wind power futures

DEFF Research Database (Denmark)

Christensen, Troels Sønderby; Pircalabu, Anca; Høg, Esben

2018-01-01

The recently introduced German wind power futures have brought the opportunity to address the problem of volume risk in wind power generation directly. In this paper we study the hedging benefits of these instruments in the context of gas-fired power plants by employing a strategy that allows...... and the dependence structure, while being straightforward and easy to implement. Based on Monte Carlo simulations from the proposed model, the results indicate that significant benefits can be achieved by using wind power futures to hedge the spot clean spark spread. Moreover, a comparison study shows...... trading in the spot clean spark spread and wind power futures. To facilitate hedging decisions, we propose a time-varying copula mixture for the joint behavior of the spot clean spark spread and the daily wind index. The model describes the data surprisingly well, both in terms of the marginals...

Perdagangan Bebas Asean-China Free Trade Areal (ACFTA) Terkait Industri Dan Iklim Investasi Di Indonesia

OpenAIRE

TRI ATIKA FEBRIANY, SH A.21211057, Jurnal Mahasiswa S2 UNTAN

2014-01-01

Countries (Indonesia, Thailand , Malaysia , Singapore , Philippines and Brunei Darussalam) with China , which is called the ASEAN -China Free Trade Agreement (ACFTA). These free trade is in the form of a tax rate reduction for goods on a regular basis up to 0% , the tariff reduction program framework of free trade between ASEAN and China, carried out in stages beginning on January 1, 2004 for EHP This thesis discusses about the implication problem of ASEAN - China Free Trade Area focusing on ...

THE WORLD TRADE ORGANIZATION (WTO FREE TRADE WITHIN FAIR TRADE CHALLENGES

Directory of Open Access Journals (Sweden)

M. Ya’kub Aiyub Kadir

2014-06-01

Full Text Available Free trade and fair trade are considered an ambiguous term with relative meanings of identification. Objectively, free and fair trade does not mean completely free and fair, but it means trade under binding rules obeyed by member countries as a consequence of their commitment after signing and ratification of the WTO agreements. Hence, this paper aims at exploring the issue and does an effort to harmonise between free trade and fair trade within the WTO system. Perdagangan bebas dan perdagangan yang adil adalah dua istilah yang ambigu maknanya. Secara obyektif, perdagangan bebas tidak bermakna bebas dan adil seluruhnya, tetapi bermakna sebuah perdagangan di bawah aturan-aturan mengikat setelah negara anggota menandatangani dan meratifikasi kesepakatan WTO. Tetapi dalam realitas kebanyakan Negara, terutama negara berkembang tidak mampu untuk membuka pasar dan menurunkan tarif secara keseluruhan. Persoalan tidak berimbangnya kekuatan, kurang demokrasi, krisis legitimasi dan dobel standar dalam WTO sistem merupakan sebuah tantangan yang masih berlanjut. Paper ini akan mengkaji persoalan ini dan berupaya mengharmonisasikan antara perdagangan bebas dan adil dalam sistem WTO.

THE WORLD TRADE ORGANIZATION (WTO FREE TRADE WITHIN FAIR TRADE CHALLENGES

Directory of Open Access Journals (Sweden)

M. Ya’kub Aiyub Kadir

2014-06-01

Full Text Available Free trade and fair trade are considered an ambiguous term with relative meanings of identification. Objectively, free and fair trade does not mean completely free and fair, but it means trade under binding rules obeyed by member countries as a consequence of their commitment after signing and ratification of the WTO agreements. Hence, this paper aims at exploring the issue and does an effort to harmonise between free trade and fair trade within the WTO system.   Perdagangan bebas dan perdagangan yang adil adalah dua istilah yang ambigu maknanya. Secara obyektif, perdagangan bebas tidak bermakna bebas dan adil seluruhnya, tetapi bermakna sebuah perdagangan di bawah aturan-aturan mengikat setelah negara anggota menandatangani dan meratifikasi kesepakatan WTO. Tetapi dalam realitas kebanyakan Negara, terutama negara berkembang tidak mampu untuk membuka pasar dan menurunkan tarif secara keseluruhan. Persoalan tidak berimbangnya kekuatan, kurang demokrasi, krisis legitimasi dan dobel standar dalam WTO sistem merupakan sebuah tantangan yang masih berlanjut. Paper ini akan mengkaji persoalan ini dan berupaya mengharmonisasikan antara perdagangan bebas dan adil dalam sistem WTO.

Market to facilitate wind and solar energy integration in the bulk power supply

Energy Technology Data Exchange (ETDEWEB)

Milligan, Michael [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Soeder, Lennart [Royal Inst. of Tech., Stockholm (Sweden); Holttinen, Hannele [VTT Energy, Espoo (Finland); Clark, Charlton [U.S. Department of Energy Washington, DC (United States); Pineda, Ivan [European Wind Energy Association, Brussels (Belgium); Collaboration: IEA Task 25 collaboration

2012-07-01

Wind and solar power will give rise to challenges in electricity markets regarding flexibility, capacity adequacy, and the participation of wind and solar generators to markets. Large amounts of wind power will have impacts on bulk power system markets and electricity prices. If the markets respond to increased wind power by increasing investments in low-capital-cost/high-marginal-cost power, the average price may remain in the same range. However, the experiences so far from Denmark, Germany, Spain, and Ireland are that the average market prices decreased because of wind power. This reduction in price may result in additional revenue insufficiency, which may be corrected with a capacity market; however, capacity markets are difficult to design. Further, the flexibility attributes of the capacity need to be considered. Markets facilitating wind and solar integration will include possibilities for trading close to delivery (either by shorter gate closure times or intraday markets). Time steps chosen for markets can enable more flexibility to be assessed. Experience from 5- and 10-minute markets has been encouraging. (orig.)

A real options approach to analyse wind energy investments under different support schemes

International Nuclear Information System (INIS)

Kitzing, Lena; Juul, Nina; Drud, Michael; Boomsma, Trine Krogh

2017-01-01

Highlights: • Real options model for wind projects considering investment timing and sizing. • Introducing a capacity constraint in the optimisation. • Addressing several uncertainty factors while still providing analytical solution. • Comparative policy analysis of investment incentives from different support schemes. • Improved quantification of trade-off between fast deployment and large projects. - Abstract: A real options model is developed to evaluate wind energy investments in a realistic and easily applicable way. Considering optimal investment timing and sizing (capacity choice), the model introduces a capacity constraint as part of the optimisation. Several correlated uncertainty factors are combined into a single stochastic process, which allows for analytical (closed-form) solutions. The approach is well suited for quantitative policy analysis, such as the comparison of different support schemes. A case study for offshore wind in the Baltic Sea quantifies differences in investment incentives under feed-in tariffs, feed-in premiums and tradable green certificates. Investors can under certificate schemes require up to 3% higher profit margins than under tariffs due to higher variance in profits. Feed-in tariffs may lead to 15% smaller project sizes. This trade-off between faster deployment of smaller projects and slower deployment of larger projects is neglected using traditional net present value approaches. In the analysis of such trade-off, previous real options studies did not consider a capacity constraint, which is here shown to decrease the significance of the effect. The impact on investment incentives also depends on correlations between the underlying stochastic factors. The results may help investors to make informed investment decisions and policy makers to strategically design renewable support and develop tailor-made incentive schemes.

Extreme winds in the Western North Pacific

Energy Technology Data Exchange (ETDEWEB)

Ott, S.

2006-11-15

A statistical model for extreme winds in the western North Pacific is developed, the region on the Planet where tropical cyclones are most common. The model is based on best track data derived mostly from satellite images of tropical cyclones. The methods used to estimate surface wind speeds from satellite images is discussed with emphasis on the empirical basis, which, unfortunately, is not very strong. This is stressed by the fact that Japanese and US agencies arrive at markedly different estimates. On the other hand, best track data records cover a long period of time and if not perfect they are at least coherent over time in their imperfections. Applying the the Holland model to the best track data, wind profiles can be assigned along the tracks. From this annual wind speed maxima at any particular point in the region can be derived. The annual maxima, in turn, are fitted to a Gumbel distribution using a generalization Abild's method that allows for data wind collected from multiple positions. The choice of this method is justified by a Monte Carlo simulation comparing it to two other methods. The principle output is a map showing fifty year winds in the region. The method is tested against observed winds from Philippine synoptic stations and fair agreement is found for observed and predicted 48 year maxima. However, the almost biasfree performance of the model could be fortuitous, since precise definitions of 'windspeed' in terms averaging time, height above ground and assumed surface roughness are not available, neither for best tracks nor for the synoptic data. The work has been carried out under Danish Research Agency grant 2104-04-0005 'Offshore wind power' and it also covers the findings and analysis carried out in connection with task 1.6 of the project 'Feasibility Assessment and Capacity Building for Wind Energy Development in Cambodia, The Philippines and Vietnam' during 2005-06 under contract 125-2004 with EU

Vertical axis wind turbines: a survey and bibliography

Energy Technology Data Exchange (ETDEWEB)

Abramovich, H

1987-01-01

The stimulus for the development of modern, big wind turbines has been the world-wide oil crisis during the seventies. Although the horizontal axis wind turbines (HAWT) was the most popular type of wind turbine the Darrieus vertical axis wind turbine (VAWT) has been recognized as a machine with competitive economic potential. The state of the art of the VAWT is reviewed. The wind turbine carrying the name of Darrieus was first proposed by the French inventor in 1925. His original patent covered a range of vertical-axis configurations but the term 'Darrieus' is now generally associated with the curved-blade geometry. In 1966 two researchers at the Canadian NRC again raised the idea of both the straight and curved-blade versions of the Darrieus VAWT.

Adequate intraday market design to enable the integration of wind energy into the European power systems

Energy Technology Data Exchange (ETDEWEB)

Weber, Christoph [University Duisburg-Essen, Chair for Energy Economics and Management Sciences, Universitaetsstrasse 12, 45 117 Essen (Germany)

2010-07-15

This contribution analyses the European electricity markets with respect to their aptitude to absorb large amounts of wind energy. Thereby in a first step the market designs of the major European power markets in France, Germany, Scandinavia, Spain and UK are reviewed, with a particular focus on liquidity in the spot and intraday markets. Then some key features of the short-term adjustments required by wind energy are discussed and the necessity of sufficient liquidity in intraday markets is highlighted. For the example of the German market subsequently the discrepancy between the physical short-term adjustment needs and the traded volumes on the intraday market is analyzed. This leads to an evaluation of proposals for improving the liquidity on the short-term market, including the use of continuous spot trading like in UK or the use of intraday auctions like in Spain. (author)

Diagnostics of Electric Equipment Windings

Directory of Open Access Journals (Sweden)

I. I. Branovitsky

2007-01-01

Full Text Available The paper presents methodology and results of the investigations pertaining to study of influence of short-circuited turns on transient electrical processes in electric motor windings. Dependence of their damped speed and value of the difference signal, obtained at reciprocal subtraction of damped oscillation curves in absence and in presence of short-circuited turns, on number of turns in the tested windings. It has been determined that damped oscillation curves, immediately attributed to short-circuited turns, have peak values along temporary axis which are areas of the largest transient process sensitivity to КЗ turns.Methodology for diagnostics of single- and three-phase electric motor windings and also other electric equipment, being realized in DO-1 device, has been developed in the paper. The men­tioned device makes it possible to carry out visual comparison and quantitative analysis of damped oscillation curves in the tested windings with standard ones which are set in the device memory and their difference signals.

Wind pressure loading for tall buidings: a case study of Warsaw Trade Tower

CSIR Research Space (South Africa)

Cwik, M

2012-12-01

Full Text Available of the building model and its surroundings, as well as the testing methods are described. The second part provides a description of the evaluation of the extreme pressure values using Gumbel distribution. Minimum and maximum wind pressure patterns over facade...

Wind Atlas for South Africa (WASA) Observational wind atlas for 10 met. stations in Northern, Western and Eastern Cape provinces

DEFF Research Database (Denmark)

Mortensen, Niels Gylling; Hansen, Jens Carsten; Kelly, Mark C.

As part of the “Wind Atlas for South Africa” project, microscale modelling has been carried out for 10 meteorological stations in Northern, Western and Eastern Cape provinces. Wind speed and direction data from the ten 60-m masts have been analysed using the Wind Atlas Analysis and Application...... Program (WAsP 11). The wind-climatological inputs are the observed wind climates derived from the WAsP Climate Analyst. Topographical inputs are elevation maps constructed from SRTM 3 data and roughness length maps constructed from SWBD data and Google Earth satellite imagery. Summaries are given...... of the data measured at the 10 masts, mainly for a 3-year reference period from October 2010 to September 2013. The main result of the microscale modelling is observational wind atlas data sets, which can be used for verification of the mesoscale modelling. In addition, the microscale modelling itself has...

AXISYMMETRIC SIMULATIONS OF HOT JUPITER–STELLAR WIND HYDRODYNAMIC INTERACTION

International Nuclear Information System (INIS)

Christie, Duncan; Arras, Phil; Li, Zhi-Yun

2016-01-01

Gas giant exoplanets orbiting at close distances to the parent star are subjected to large radiation and stellar wind fluxes. In this paper, hydrodynamic simulations of the planetary upper atmosphere and its interaction with the stellar wind are carried out to understand the possible flow regimes and how they affect the Lyα transmission spectrum. Following Tremblin and Chiang, charge exchange reactions are included to explore the role of energetic atoms as compared to thermal particles. In order to understand the role of the tail as compared to the leading edge of the planetary gas, the simulations were carried out under axisymmetry, and photoionization and stellar wind electron impact ionization reactions were included to limit the extent of the neutrals away from the planet. By varying the planetary gas temperature, two regimes are found. At high temperature, a supersonic planetary wind is found, which is turned around by the stellar wind and forms a tail behind the planet. At lower temperatures, the planetary wind is shut off when the stellar wind penetrates inside where the sonic point would have been. In this regime mass is lost by viscous interaction at the boundary between planetary and stellar wind gases. Absorption by cold hydrogen atoms is large near the planetary surface, and decreases away from the planet as expected. The hot hydrogen absorption is in an annulus and typically dominated by the tail, at large impact parameter, rather than by the thin leading edge of the mixing layer near the substellar point

AXISYMMETRIC SIMULATIONS OF HOT JUPITER–STELLAR WIND HYDRODYNAMIC INTERACTION

Energy Technology Data Exchange (ETDEWEB)

Christie, Duncan; Arras, Phil; Li, Zhi-Yun [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States)

2016-03-20

Gas giant exoplanets orbiting at close distances to the parent star are subjected to large radiation and stellar wind fluxes. In this paper, hydrodynamic simulations of the planetary upper atmosphere and its interaction with the stellar wind are carried out to understand the possible flow regimes and how they affect the Lyα transmission spectrum. Following Tremblin and Chiang, charge exchange reactions are included to explore the role of energetic atoms as compared to thermal particles. In order to understand the role of the tail as compared to the leading edge of the planetary gas, the simulations were carried out under axisymmetry, and photoionization and stellar wind electron impact ionization reactions were included to limit the extent of the neutrals away from the planet. By varying the planetary gas temperature, two regimes are found. At high temperature, a supersonic planetary wind is found, which is turned around by the stellar wind and forms a tail behind the planet. At lower temperatures, the planetary wind is shut off when the stellar wind penetrates inside where the sonic point would have been. In this regime mass is lost by viscous interaction at the boundary between planetary and stellar wind gases. Absorption by cold hydrogen atoms is large near the planetary surface, and decreases away from the planet as expected. The hot hydrogen absorption is in an annulus and typically dominated by the tail, at large impact parameter, rather than by the thin leading edge of the mixing layer near the substellar point.

Winds of change: First Nations in the supply chain

International Nuclear Information System (INIS)

Soulliere, Marc

2011-01-01

TWN Wind Power is a First Nations company which aims at providing First Nation communities with the opportunity to develop small wind power projects to produce energy without harming their environment. Through its work in energy production, the company creates jobs and revenues in addition to protecting First Nations against electricity rate increases. The objective of this paper is to present a successful wind turbine project. This Band school wind turbine project consisted of installing a 5 kW wind turbine at a school in Keremeos and educating students in renewable energies field. The project was planned to be completed in October 2011. In addition to this project, TWN Wind Power has also completed other projects in Oklahoma, South Dakota, British Columbia, Nova Scotia and Saskatchewan successfully. This presentation highlighted the work carried out by TWN Wind Power to develop wind energy projects within First Nations communities.

Winds of change: First Nations in the supply chain

Energy Technology Data Exchange (ETDEWEB)

Soulliere, Marc [TWN Wind Power Inc. (Canada)

2011-07-01

TWN Wind Power is a First Nations company which aims at providing First Nation communities with the opportunity to develop small wind power projects to produce energy without harming their environment. Through its work in energy production, the company creates jobs and revenues in addition to protecting First Nations against electricity rate increases. The objective of this paper is to present a successful wind turbine project. This Band school wind turbine project consisted of installing a 5 kW wind turbine at a school in Keremeos and educating students in renewable energies field. The project was planned to be completed in October 2011. In addition to this project, TWN Wind Power has also completed other projects in Oklahoma, South Dakota, British Columbia, Nova Scotia and Saskatchewan successfully. This presentation highlighted the work carried out by TWN Wind Power to develop wind energy projects within First Nations communities.

Energy trading

International Nuclear Information System (INIS)

Glachant, J.M.; Kimman, R.; Schweickardt, H.E.

2001-05-01

This document brings together 18 testimonies of experts about energy trading: 1 - the energy trading experience on European deregulated markets: structure of deregulated energy markets in Europe, case study: a two years experience of a power exchange in western Europe, case study: European energy exchanges (experience of spot and future trading), case study: risk management on energy deregulated markets; 2 - the trading activity environment and realities in France: the French electrical law and the purchase for resale, experience feedback: status after 3 months of trading in France (the first experience of a French producer), the access to the power transportation network, which legal constraints for trading in France, the access of eligible clients to the French power market, conditions of implementation of a power exchange market in France, which real trading possibilities in France for producers and self-producers in the legal frame, case study: the role of trading in the company (main part or link to process), convergence of gas and electricity markets, gas-electricity trading: which pricing models; 3 - risk management and use of new technologies potentiality, the results outside the French borders: case study: what differences between the European and US markets, prices volatility and commodity risk management: towards the on-line trading, role and developments of E-business in energy trading, how to simplify trade in a liberalized market. (J.S.)

Wind energy and Swiss hydro power

International Nuclear Information System (INIS)

Ott, W.; Baur, M.; Fritz, W.; Zimmer, Ch.; Feldmann, J.; Haubrich, H.-J.; Dany, G.; Schmoeller, H.; Hartmann, T.

2004-01-01

This report for the Swiss Federal Office of Energy (SFOE) examines the possibilities of using Switzerland's hydropower generation facilities as a means of control and as a capacity-reserve for a European power system that includes a considerable amount of wind-generated electricity. The aims of the study - the analysis of possible changes in power availability and of the relative importance of peak load compensation, economic optimisation potential for the use of Swiss hydropower and organisational aspects - are presented. Various methods for organising production timetables and trading are looked at, as are future developments in the European power market. Methods of assessment of the value of Swiss hydropower installations are discussed in detail and possibilities of increasing capacity are discussed. The report is concluded with recommendations on the participation of Swiss hydropower in the market for regulation energy and the development of associated strategies. Also, environmental aspects are examined and the influence of national wind-energy concepts are discussed

Slave trade and slavery on the Swahili coast (1500-1750)

OpenAIRE

Vernet, Thomas

2009-01-01

This paper offers a reappraisal of the slave trade networks linked to the Swahili Coast before the mid-eighteenth century. It is based on extensive research carried out in Portuguese archives and other material.

MOD-1 Wind Turbine Generator Analysis and Design Report, Volume 2

Science.gov (United States)

1979-01-01

The MOD-1 detail design is appended. The supporting analyses presented include a parametric system trade study, a verification of the computer codes used for rotor loads analysis, a metal blade study, and a definition of the design loads at each principal wind turbine generator interface for critical loading conditions. Shipping and assembly requirements, composite blade development, and electrical stability are also discussed.

International trade law perspectives on paperless trade and inclusive digital trade

OpenAIRE

Mitchell, Andrew D.; Mishra, Neha

2017-01-01

Cross-border paperless trade is increasingly important to generate economic gains in a digitalised economy. Several developing and least developed countries will need to modernise their domestic laws and regulations to facilitate cross-border electronic transmissions, particularly to promote cloud computing and electronic payments. In recent trade agreements, trading partners have committed to deeper and more comprehensive provisions on electronic commerce, including adopting domestic laws on...

Wind Power Fluctuation Smoothing Controller Based on Risk Assessment of Grid Frequency Deviation in an Isolated System

DEFF Research Database (Denmark)

Lin, Jin; Sun, Yuanzhang; Song, Yonghua

2013-01-01

a smoothing controller to suppress the power fluctuation from doubly-fed induction generator (DFIG)-based wind farm. This controller consists of threemain functionality components: risk assessmentmodel, wind turbine rotor speed optimizer, and rotor speed upper limiter. In order to avoid unnecessary energy...... curve with reduced output so that a trade-off between fluctuation smoothing and energy loss is achieved. Subsequently, the controller limits the maximum rotor speed to shift down the power curve of wind power plant based on the optimal wind turbine rotor speed. Therefore, the power fluctuation......Wind power fluctuation raises the security concern of grid frequency deviation, especially for an isolated power system. Thus, better control methodology needs to be developed to smooth the fluctuation without excessive spillage. Based on an actual industrial power system, this paper proposes...

Wind power: Italian auto-production legislation (ISES convention)

International Nuclear Information System (INIS)

Mari, G.

1991-01-01

With reference to what was discussed at the Bologna (Italy) June 1991 ISES (International Solar Energy Society) convention on wind energy, this paper summarizes the Italian legislative framework relative to on-site power generation and outlines the National Energy Plan objectives regarding the promotion of the use, by industry, of renewable energy sources. Brief notes are also provided on wind energy promotional activities being carried out by ENEL (the Italian National Energy Board), ENEA (Italian Agency for New Technologies, Energy and the Environment), and EWEA (the European Wind Energy Association)

The extension of the international trade

International Nuclear Information System (INIS)

Buch, Tomas

1998-01-01

INVAP, a company pertaining to the Rio Negro province and controlled by the National Atomic Energy Commission (CNEA), has been instrumental for the international expansion of the Argentine nuclear trade, including the provision of Argentine research reactors to Algeria and Egypt. The history of the negotiations carried out with about twenty countries is shortly summarized and the scope of the supply of the major contracts is described

Measures of International Manufacturing and Trade of Clean Energy Technologies

Energy Technology Data Exchange (ETDEWEB)

Engel-Cox, Jill; Sandor, Debbie; Keyser, David; Mann, Margaret

2017-05-25

The technologies that produce clean energy, such as solar photovoltaic panels and lithium ion batteries for electric vehicles, are globally manufactured and traded. As demand and deployment of these technologies grows exponentially, the innovation to reach significant economies of scale and drive down energy production costs becomes less in the technology and more in the manufacturing of the technology. Manufacturing innovations and other manufacturing decisions can reduce costs of labor, materials, equipment, operating costs, and transportation, across all the links in the supply chain. To better understand the manufacturing aspect of the clean energy economy, we have developed key metrics for systematically measuring and benchmarking international manufacturing of clean energy technologies. The metrics are: trade, market size, manufacturing value-added, and manufacturing capacity and production. These metrics were applied to twelve global economies and four representative technologies: wind turbine components, crystalline silicon solar photovoltaic modules, vehicle lithium ion battery cells, and light emitting diode packages for efficient lighting and other consumer products. The results indicated that clean energy technologies are being developed via complex, dynamic, and global supply chains, with individual economies benefiting from different technologies and links in the supply chain, through both domestic manufacturing and global trade.

Wind farms and rural tourism: A Portuguese case study of residents’ and visitors’ perceptions and attitudes

Directory of Open Access Journals (Sweden)

Silva Luís

2017-12-01

Full Text Available Residents’ and visitors’ perceptions of and attitudes towards existing wind farms, as well as the perceived impact of wind farms on tourism, are examined in this article with reference to a built heritage site in the Portuguese countryside. Based on a set of semi-structured interviews, the paper sheds light on the positive impact that the community’s or local actors’ involvement in the constitution, management and decision-making processes has on the residents’ perceptions and attitudes regarding wind farms, and also on the trade-off with the perceived effect of wind farms on local tourism. Moreover, it shows that although most visitors criticised the proximity of wind turbines to medieval architecture, a clear majority of them accepted their presence and virtually all of them stated that these facilities had no impact on their choice of destination.

Unsteady aerodynamic analysis for offshore floating wind turbines under different wind conditions.

Science.gov (United States)

Xu, B F; Wang, T G; Yuan, Y; Cao, J F

2015-02-28

A free-vortex wake (FVW) model is developed in this paper to analyse the unsteady aerodynamic performance of offshore floating wind turbines. A time-marching algorithm of third-order accuracy is applied in the FVW model. Owing to the complex floating platform motions, the blade inflow conditions and the positions of initial points of vortex filaments, which are different from the fixed wind turbine, are modified in the implemented model. A three-dimensional rotational effect model and a dynamic stall model are coupled into the FVW model to improve the aerodynamic performance prediction in the unsteady conditions. The effects of floating platform motions in the simulation model are validated by comparison between calculation and experiment for a small-scale rigid test wind turbine coupled with a floating tension leg platform (TLP). The dynamic inflow effect carried by the FVW method itself is confirmed and the results agree well with the experimental data of a pitching transient on another test turbine. Also, the flapping moment at the blade root in yaw on the same test turbine is calculated and compares well with the experimental data. Then, the aerodynamic performance is simulated in a yawed condition of steady wind and in an unyawed condition of turbulent wind, respectively, for a large-scale wind turbine coupled with the floating TLP motions, demonstrating obvious differences in rotor performance and blade loading from the fixed wind turbine. The non-dimensional magnitudes of loading changes due to the floating platform motions decrease from the blade root to the blade tip. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Global climate-friendly trade : Canada's chance to clean up

International Nuclear Information System (INIS)

Goldfarb, D.

2010-03-01

This paper discussed the global trade and investment in climate-friendly technologies, Canada's current position in this market, and the policy changes that are necessary for Canadian businesses to gain a stronger foothold in this sector. The global market for climate-friendly technologies is growing rapidly, but Canadian businesses have generally failed to exploit opportunities to export climate-friendly technologies and have generally lagged other countries in adopting such technologies developed elsewhere. Although Canadian businesses generally underperform in this sector, Canada does have notable strengths in 13 identified areas, including waste management technologies, energy technologies, and in parts of the value chains associated with wind and solar power. Targeting these areas of relative strength for further development could position Canada as a global leader in some climate-friendly technologies. For this to happen, Canadian governments need to establish clear policies, invest in research and development, and remove domestic and international barriers to the development and trade in climate-friendly technologies. 30 refs., 5 tabs., 5 figs.

Floating wind generators offshore wind farm: Implications for structural loads and control actions

International Nuclear Information System (INIS)

Garcia, E.; Morant F, Quiles E.; Correcher, A.

2009-01-01

This paper describes the work currently carried out in the design of floating wind generators and their involvement in the future development of power generation in marine farms in depths exceeding 20 m. We discuss the main issues to be taken into account in the design of floating platforms, including the involvement of structural loads they bear. Also from a standpoint of control engineering are discussed strategies to reduce structural loads such a system to ensure adequate durability and therefore ensuring their economic viability. Finally, the abstract modeling tools for floating wind turbines that can be used in both structural design and the design of appropriate control algorithms

Fair trade for coffee producing small-scale farmers in Mexico

Directory of Open Access Journals (Sweden)

Nam kwon Mun

2012-10-01

Full Text Available The agriculture played an important role in the industrialization process of Mexico. However, the agricultural policy of State has isolated small scale farmers, giving priority just to large agricultural exporters. This study analyzes the implications that can have fair trade for the Mexican small scale farmers. The fair trade tries to cover the production cost and basic necessities for the small scale farmers, making direct ties between producers and consumers. This type of linkage guarantees the minimum price and the extra social payment to the small scale farmers, grouped in cooperatives o associations.Coffee is one of the most known fair trade product, and Mexico is one of the most important coffer exporters of the world. The fair trade of coffee production where many small farmers work is carried out by cooperative like UCIRI (Unión de Comunidades Indígenas de la Región Istmo. The case study shows that fair trade cannot provide complete answers to the all problems that have small farmers. But, since fair trade tries to promote small farmers well-being and many small farmers could get rid of extreme poverty thanks to fair trade, it might be possible to say that fair trade can be one valuable option for the sustainable development of small farmers.

Active Power Dispatch Method for a Wind Farm Central Controller Considering Wake Effect

DEFF Research Database (Denmark)

Tian, Jie; Su, Chi; N. Soltani, Mohsen

2014-01-01

With the increasing integration of the wind power into the power system, wind farm are required to be controlled as a single unit and have all the same control tasks as conventional power plants. The wind farm central controller receives control orders from Transmission System Operator (TSO), the...... Optimization (PSO) is used to obtain the optimal wind power for each wind turbine. A case study is carried out. The available wind power of the wind farm was compared between the traditional dispatch method and the proposed dispatch method with the consideration of the wake effect....

Landscape impact assessment of wind farm development in Dyfed

International Nuclear Information System (INIS)

Blandford, C.; White, S.; Garrad, A.D.; Morgan, C.A.

1992-01-01

Chris Blandford Associates, in association with Garrad Hassan and Partners, was commissioned to carry out a landscape impact assessment of wind turbine development in Dyfed. The study aims to identify those areas in Dyfed where, in terms of landscape impact, local authorities might seek either to exclude or encourage wind turbine development; provide guidelines to assist local authorities in judging the impact of wind turbine developments on the landscape; provide a basis and framework for the preparation of planning policy guidelines for acceptable wind turbine and wind farm developments in Dyfed. The study context reviews current Government energy and planning policies for the encouragement of wind turbine developments, as set out in the ''non-fossil fuel obligation'' and the draft planning policy guidance note for renewable energy published last December. (author)

Performance of spanish wind turbines; Estadisticas de produccion de parques eolicos en Espana

Energy Technology Data Exchange (ETDEWEB)

Lago, C

1995-07-01

In this document we can find a statistical evaluation for the wind energy generation from each spanish wind farm referred to 1994, going on with the work that has been carried out since 1992, by initiative of the Wind Energy Division from Renewable Energy Institute. The purpose of this work is to contribute with interesting information for the wind environment and offer a global view from monthly performances of different wind farms. (Author)

Improved reliability of wind turbine towers with active tuned mass dampers (ATMDs)

Science.gov (United States)

Fitzgerald, Breiffni; Sarkar, Saptarshi; Staino, Andrea

2018-04-01

Modern multi-megawatt wind turbines are composed of slender, flexible, and lightly damped blades and towers. These components exhibit high susceptibility to wind-induced vibrations. As the size, flexibility and cost of the towers have increased in recent years, the need to protect these structures against damage induced by turbulent aerodynamic loading has become apparent. This paper combines structural dynamic models and probabilistic assessment tools to demonstrate improvements in structural reliability when modern wind turbine towers are equipped with active tuned mass dampers (ATMDs). This study proposes a multi-modal wind turbine model for wind turbine control design and analysis. This study incorporates an ATMD into the tower of this model. The model is subjected to stochastically generated wind loads of varying speeds to develop wind-induced probabilistic demand models for towers of modern multi-megawatt wind turbines under structural uncertainty. Numerical simulations have been carried out to ascertain the effectiveness of the active control system to improve the structural performance of the wind turbine and its reliability. The study constructs fragility curves, which illustrate reductions in the vulnerability of towers to wind loading owing to the inclusion of the damper. Results show that the active controller is successful in increasing the reliability of the tower responses. According to the analysis carried out in this paper, a strong reduction of the probability of exceeding a given displacement at the rated wind speed has been observed.

Structural Analysis of Basalt Fiber Reinforced Plastic Wind Turbine Blade

Directory of Open Access Journals (Sweden)

Mengal Ali Nawaz

2014-07-01

Full Text Available In this study, Basalt fiber reinforced plastic (BFRP wind turbine blade was analyzed and compared with Glass fiber reinforced plastic blade (GFRP. Finite element analysis (FEA of blade was carried out using ANSYS. Data for FEA was obtained by using rule of mixture. The shell element in ANSYS was used to simulate the wind turbine blade and to conduct its strength analysis. The structural analysis and comparison of blade deformations proved that BFRP wind turbine blade has better strength compared to GFRP wind turbine blade.

Sensitivity of ocean oxygenation to variations in tropical zonal wind stress magnitude

Science.gov (United States)

Ridder, Nina N.; England, Matthew H.

2014-09-01

Ocean oxygenation has been observed to have changed over the past few decades and is projected to change further under global climate change due to an interplay of several mechanisms. In this study we isolate the effect of modified tropical surface wind stress conditions on the evolution of ocean oxygenation in a numerical climate model. We find that ocean oxygenation varies inversely with low-latitude surface wind stress. Approximately one third of this response is driven by sea surface temperature anomalies; the remaining two thirds result from changes in ocean circulation and marine biology. Global mean O2 concentration changes reach maximum values of +4 μM and -3.6 μM in the two most extreme perturbation cases of -30% and +30% wind change, respectively. Localized changes lie between +92 μM under 30% reduced winds and -56 μM for 30% increased winds. Overall, we find that the extent of the global low-oxygen volume varies with the same sign as the wind perturbation; namely, weaker winds reduce the low-oxygen volume on the global scale and vice versa for increased trade winds. We identify two regions, one in the Pacific Ocean off Chile and the other in the Indian Ocean off Somalia, that are of particular importance for the evolution of oxygen minimum zones in the global ocean.

Wind-power plant

Energy Technology Data Exchange (ETDEWEB)

Kling, A

1976-08-26

The invention is concerned with a wind-power plant whose rotor axis is pivoted in the supporting structure and swingable around an axis of tilt, forming an angle with the rotor axis and the vertical axis, and allowing precession of the rotor. On changes of wind direction an electric positioning device is moving the rotor axis into the new direction in such a way that no precession forces are exerted on the supporting structure and this one may very easily be held. Instead of one rotor, also a type with two coaxial, co-planar countercurrent rotors may be used. Each of the two countercurrent rotors is carrying a number of magnetic poles, distributed all over the circumference, acting together with the magnetic poles of the other rotor. At least the poles of one rotor have electric line windings being connected by leads with a collector so that the two rotors form the two parts of a power generator being each rotatable with respect to the other ('stator' and 'rotor').

Wind power and the conditions at a liberalized power market

International Nuclear Information System (INIS)

Morthorst, P.E.

2003-01-01

Wind power is undergoing a rapid development nationally as well as globally and in a number of countries covers an increasing part of the power supply. At the same time an ongoing liberalization of power markets is taking place and to an increasing extent the owners of wind power plants will themselves have to be responsible for trading the power at the spot market and financially handling the balancing. In the western part of Denmark (Jutland/Funen area), wind-generated power from time to time covers almost 100% of total power consumption. Therefore some examples are chosen from this area to analyse in more detail how well large amounts of wind power in the short-term are handled at the power spot market. It turns out that there is a tendency that more wind power in the system in the short run leads to relatively lower spot prices, while less wind power implies relatively higher spot prices, although, with the exception of December 2002, in general no strong relationship is found. A stronger relationship is found at the regulating market, where there is a fairly clear tendency that the more wind power produced, the higher is the need for down-regulation, and, correspondingly, the less wind power produced, the higher is the need for up-regulation. In general for the Jutland/Funen area the average cost of down-regulation is calculated as 1 2 c euros/kWh regulated for 2002, while the cost of up-regulation amounts to 0 7 c euros/kWh regulated. (author)

Wind and area potential analysis of the Lower Saxony coast

International Nuclear Information System (INIS)

Pahlke, T.; Gerdes, G.; Keuper, A.

1993-01-01

An analysis of the wind and area potential is carried out for 10 areas at the Lower Saxony coast, on behalf of the Lower Saxony Ministry of the Environment. The processes for determining suitable areas, the wind speeds and the possible amounts of energy are introduced. (orig.) [de

Impact of Market Regulations on the Development of Wind Power - An International Comparison

International Nuclear Information System (INIS)

Ackermann, Thomas; Soeder, Lennart

2000-01-01

This paper presents and briefly evaluates the most important existing market regulations and market schemes regarding its influence on the development of wind power. The evaluation of the existing market regulations focuses on the incentives provided by the various instruments to reduce production costs. The instruments and schemes are: Feed-in Tariffs, Net Metering, Bidding Process, Fixed Quotas, Green Certificate Trading, Green Power Exchange, Green Pricing. In addition, the impact of market regulations for international electricity markets with a power exchange are investigated. The analysis showed that new wind power generation can faces significant market barriers. (author)

Isolated systems with wind power. Main report

DEFF Research Database (Denmark)

Lundsager, P.; Bindner, Henrik W.; Clausen, Niels-Erik

2001-01-01

The overall objective of this research project is to study the development of methods and guidelines rather than "universal solutions" for the use of wind energy in isolated communities. The main specific objective of the project is to develop and present amore unified and generally applicable...... approach for assessing the technical and economical feasibility of isolated power supply systems with wind energy. As a part of the project the following tasks were carried out: Review of literature, fieldmeasurements in Egypt, development of an inventory of small isolated systems, overview of end...... for Isolated Systems with Wind Power, applicable for international organisations such as donoragencies and development banks....

IDENTIFICATION OF WIND LOAD APPLIED TO THREE-DIMENSIONAL STRUCTURES BY VIRTUE OF ITS SIMULATION IN THE WIND TUNNEL

Directory of Open Access Journals (Sweden)

Doroshenko Sergey Aleksandrovich

2012-10-01

Full Text Available The authors discuss wind loads applied to a set of two buildings. The wind load is simulated with the help of the wind tunnel. In the Russian Federation, special attention is driven to the aerodynamics of high-rise buildings and structures. According to the Russian norms, identification of aerodynamic coefficients for high-rise buildings, as well as the influence of adjacent buildings and structures, is performed on the basis of models of structures exposed to wind impacts simulated in the wind tunnel. This article deals with the results of the wind tunnel test of buildings. The simulation was carried out with the involvement of a model of two twenty-three storied buildings. The experiment was held in a wind tunnel of the closed type at in the Institute of Mechanics of Moscow State University. Data were compared at the zero speed before and after the experiment. LabView software was used to process the output data. Graphs and tables were developed in the Microsoft Excel package. GoogleSketchUp software was used as a visualization tool. The three-dimensional flow formed in the wind tunnel can't be adequately described by solving the two-dimensional problem. The aerodynamic experiment technique is used to analyze the results for eighteen angles of the wind attack.

Regional tendencies of extreme wind characteristics in Hungary

Science.gov (United States)

Radics, Dr.; Bartholy, Dr.; Péliné

2009-09-01

Human activities have substantial effects on climate system. It has already accepted that change in the long-term climatic mean state will have significant consequences in the global economy and society, but the most important effects of climate change may come from changes in the intensity and frequency of climatic extremes. It is therefore of great interest to document the extremes of surface wind that could assist in estimating the regional effects of climate change. The research presented is based on 34-year-long (1975-2008) wind (speed, direction, and wind gust) data sets of 36 Hungarian synoptic meteorological stations. After processing (including digitalisation of old instrumental records, quality control and homogenisation of wind time series) the measured wind data sets, time series and complex wind climate analysis were carried out. Spatial and temporal distributions of mean and extreme wind climate characteristics were estimated, wind extremes and trends were interpolated and mapped over the country. Finally, measured and reanalysed (ERA40) wind data were compared over Hungary, in order to verify not only the validity of ERA40 reanalysed data sets, but the adaptability of climate simulation results in estimation of regional climate change effects.

Integrated installation for offshore wind turbines

Energy Technology Data Exchange (ETDEWEB)

Way, J.; Bowerman, H.

2003-07-01

A project to investigate the feasibility of integrating the offshore installation of foundation, turbine and tower for offshore wind turbines into one operation is described. Three separate objectives are listed. They are: (1) Telescopic tower study - reversible process incorporating lift and lock mechanisms; (2) Transportation study - technical and economic feasibility of transporting and installing a wind turbine unit via a standard barge with minimal conversion and (3) Self-burial system study - to demonstrate the feasibility of self burial of a slab foundation via controlled jetting beneath the slab. The background to the study and the proposed concepts are discussed. The work carried out to date and the costs are reported together with the findings. Recommendations for future work are listed. The work was carried out by Corus UK Ltd and is managed by Future Energy Solutions for the DTI.

STRUCTURE AND SHARES IN THE ROMANIAN INTERNATIONAL TRADE

Directory of Open Access Journals (Sweden)

Elena TOMA

2014-04-01

Full Text Available An analysis of a wider range of external trade sector of Romania was carried out in this paper. Main purpose of the paper was identification of the products which have submitted during the period 2002-2011 a wide dynamic with regard to trade of Romania, the total and in particular with the EU countries. The methodology used in this respect was detailed analysis of the data, of the structure of imports and exports and the dynamics of these exchanges during the ten years. Thus, we have identified productions which have had a production upward or downward trend in the structure of total trade. It is a case of grain, milk and seeds and oleaginous fruits and tobacco, which has had a positive development in imports and exports. Tobacco and meat products for the imports and live livestock and vegetables for the exports have registered a decreased share.

Noise measurements in 4 wind turbine farms

International Nuclear Information System (INIS)

Van Zuylen, E.J.; Koerts, M.

1993-02-01

The title wind turbine arrays are situated in Herbayum (Newinco 23PI250), Callantsoog (Bouma 160/20), Noordoostpolder (Windmaster WM300), and Ulketocht (Newinco 500 kW). Measurements were carried out by means of the so-called Ecofys Correlating Noise Meter to determine the source level of the wind turbines. The resulting source level as a function of the wind speed is interpolated to a source level for a wind speed of 8 m/s at 10 m height, on the basis of which the noise contours can be calculated. The noise contours are determined to analyze the noise load for people living in the neighbourhood of the wind parks. The source levels are compared with values as indicated in certificates, which are granted on the basis of a so-called Restricted Quality Certificate (BKC, abbreviated in Dutch) or the new standard NNI 6096/2 for the above-mentioned wind turbines. In general the results of this study agree quite well with the certified values. 12 figs., 7 tabs., 6 refs

Diode Laser Assisted Filament Winding of Thermoplastic Matrix Composites

Science.gov (United States)

Quadrini, Fabrizio; Squeo, Erica Anna; Prosperi, Claudia

2010-01-01

A new consolidation method for the laser-assisted filament winding of thermoplastic prepregs is discussed: for the first time a diode laser is used, as well as long glass fiber reinforced polypropylene prepregs. A consolidation apparatus was built by means of a CNC motion table, a stepper motor and a simple tensioner. Preliminary tests were performed in a hoop winding configuration: only the winding speed was changed, and all the other process parameters (laser power, distance from the laser focus, consolidation force) were kept constant. Small wound rings with an internal diameter of 25 mm were produced and compression tests were carried out to evaluate the composite agglomeration in dependence of the winding speed. At lower winding speeds, a strong interpenetration of adjacent layers was observed.

Variations in long term wind speed during different decades in ...

Indian Academy of Sciences (India)

A study has been carried out by comparing the extreme wind speeds estimated based on. NCEP/NCAR reanalysis data for 100 ... Analysis has shown slight upward trend in the annual maximum wind for location off Machilipatnam with ... storm surges and also it affects the offshore marine operations. Several studies were ...

Additive versus multiplicative trade costs and the gains from trade

DEFF Research Database (Denmark)

Sørensen, Allan

This paper addresses welfare effects from trade liberalization in a heterogeneous-fi…rms trade model including the empirically important per-unit (i.e. additive) trade costs in addition to the conventional iceberg (i.e. multiplicative) and fi…xed trade costs. The novel contribution of the paper...... is the result that the welfare gain for a given increase in trade openness is higher for reductions in per-unit (additive) trade costs than for reductions in iceberg (multiplicative) trade costs. The ranking derives from differences in intra-industry reallocations and in particular from dissimilar impacts...

Numerical simulation of a mistral wind event occuring

Science.gov (United States)

Guenard, V.; Caccia, J. L.; Tedeschi, G.

2003-04-01

The experimental network of the ESCOMPTE field experiment (june-july 2001) is turned into account to investigate the Mistral wind affecting the Marseille area (South of France). Mistral wind is a northerly flow blowing across the Rhône valley and toward the Mediterranean sea resulting from the dynamical low pressure generated in the wake of the Alps ridge. It brings cold, dry air masses and clear sky conditions over the south-eastern part of France. Up to now, few scientific studies have been carried out on the Mistral wind especially the evolution of its 3-D structure so that its mesoscale numerical simulation is still relevant. Non-hydrostatic RAMS model is performed to better investigate this mesoscale phenomena. Simulations at a 12 km horizontal resolution are compared to boundary layer wind profilers and ground measurements. Preliminary results suit quite well with the Mistral statistical studies carried out by the operational service of Météo-France and observed wind profiles are correctly reproduced by the numerical model RAMS which appears to be an efficient tool for its understanding of Mistral. Owing to the absence of diabatic effect in Mistral events which complicates numerical simulations, the present work is the first step for the validation of RAMS model in that area. Further works will consist on the study of the interaction of Mistral wind with land-sea breeze. Also, RAMS simulations will be combined with aerosol production and ocean circulation models to supply chemists and oceanographers with some answers for their studies.

Who should own the nearshore wind turbines?

DEFF Research Database (Denmark)

Jensen, Louise Krog; Sperling, Karl

This report examines the possibility for non-profit organisations to participate in tenders for nearshore wind turbines in Denmark under the current frame-work conditions in the area. The point of departure is a case study of the non-profit organisation Wind People’s attempt to participate...... with a popular project in the Danish tender for 350 MW nearshore wind turbines. A series of in-depth interviews have been carried out with Wind People’s staff in order to make an in-depth analysis of their actions and experiences of entering into the market for nearshore wind turbines. The report concludes...... the way for non-profit organisations to be able to enter the market, however, as the study shows that the established actors in the market also have a large influence on who is allowed to enter the market. The results of the report are a number of recommendations to the Danish politicians and the Danish...

Estimating the elasticity of trade: the trade share approach

OpenAIRE

Mauro Lanati

2013-01-01

Recent theoretical work on international trade emphasizes the importance of trade elasticity as the fundamental statistic needed to conduct welfare analysis. Eaton and Kortum (2002) proposed a two-step method to estimate this parameter, where exporter fixed effects are regressed on proxies for technology and wages. Within the same Ricardian model of trade, the trade share provides an alternative source of identication for the elasticity of trade. Following Santos Silva and Tenreyro (2006) bot...

Determining Wind Erosion in the Great Plains

OpenAIRE

Elwin G. Smith; Burton C. English

1982-01-01

Wind erosion is defined as the movement of soil particles resulting from strong turbulent winds. The movement of soil particles can be categorized as suspension, saltation, or surface creep. Fine soil particles can be suspended in the atmosphere and carried for great distances. Particles too large to be suspended move in a jumping action along the soil surface, known as saltation. Heavier particles have a rolling movement along the surface and this type of erosion is surface creep.

Wind Farms Community Engagement Good Practice Review

DEFF Research Database (Denmark)

Aitken, Mhairi; Haggett, Claire; Rudolph, David Philipp

2014-01-01

This report sets out the findings of a review of community engagement for wind farm developments. We focus in particular on the engagement carried out by developers with communities. The aims of the study were to evaluate current good practice for engaging people in decision making about on......- and offshore wind farms in different European countries; to evaluate the effect that different practices have on public opinion and acceptance; and to make relevant recommendations for Scottish policy and planning....

Prevalence of Gastrointestinal Parasites among the Trade Donkeys ...

African Journals Online (AJOL)

A prevalence study was carried out to determine the gastrointestinal parasites among trade donkeys brought to the three major donkey markets of Alkaleri, Bauchi and Soro in Bauchi State, Nigeria. A total of 116 donkeys comprising of 69 Idabari, 24 Duni and 23 Auraki breeds were randomly selected and examined for ...

Effect of unbalanced voltage on windings temperature, operational life and load carrying capacity of induction machine

Energy Technology Data Exchange (ETDEWEB)

Gnacinski, P. [Gdynia Maritime University, Department of Ship Electrical Power Engineering, Morska Street 83, 81-225 Gdynia (Poland)

2008-04-15

This paper investigates the influence of the CVUF angle on the windings temperature rise and the derating factor of an induction machine supplied with unbalanced voltage. The effect of simultaneous voltage unbalance and harmonics on its operational life is analyzed as well. The results of calculations and experimental investigations are presented for two induction cage machines of rated power 3 and 5.5 kW. (author)

Plurilateral Trade Deals: An Alternative for Multilateral Trade Agreements?

Directory of Open Access Journals (Sweden)

Agnes Ghibuțiu

2016-04-01

Full Text Available While multilateral trade negotiations under the World Trade Organization (WTO continue to be in impasse, plurilateral trade negotiations – i.e. among a group of WTO members – have intensified in recent years, and also recorded a series of concrete results in liberalizing specific sectors of international trade. Hence, there is a widely shared view that plurilateral trade negotiations could be an alternative for the multilateral ones. This paper aims to answer the following questions: What are plurilateral trade agreements? Which are the reasons behind the surge in plurilateral negotiations in recent years? What are the main achievements in liberalizing trade at the plurilateral level? What are the advantages of plurilateral negotiations relative to multilateral ones, and why are they considered an attractive alternative for negotiations at the multilateral level?

Discourse on corruption counteraction in network trade

Directory of Open Access Journals (Sweden)

Leonid A. Zhigun

2015-12-01

Full Text Available Objective to determine the specific forms of corruption and promising methods to counteract corruption in network trade. Methods the combination of inductive observations comparisons generalizations facts and trends of corruption in network trade with a logical analytical deduction of economic theories and the corruption concept are the basis of the study and provide an opportunity on the one hand to assess the level of compliance of theoretical concepts of corruption with the practice and on the other handnbsp to determine their applicability to organize opposition and create conditions to prevent its occurrence to summarize the features of corruption in the form of a kickback the discourse method was applied in this work. Results on the basis of theoretical provisions and facts of corruption in trade it is proved that it has typical characteristics of corruption in commercial and nonprofit organizations. The key reasons are identified why corruption occurs in trade. Among them supply of poor quality goods at inflated prices leading to bribery in the form of laquopersonal bonusraquo to administrator of the trading organization when selling goods by an unscrupulous supplier and also supply goods to the trade organizations which will not buy without kickback. Most of these corrupt deals are carried out by natural monopolies in the form of state and municipal procurement. In some cases the kickback is the argument stimulating the decision to introduce new and advanced technologies. The factors that lead to corruption in trade are listed and reasonable methods to counteract it are grounded allowing to create conditions for its eradication in other branches of business as well. Scientific novelty for the first time a generalization has been made about the deficit as the driving force in the mechanism when the bribegivers and bribetakers change places. Practical significance the main provisions and conclusions of the article can be used in the

The Position of Suitcase Trading in Turkey’s Foreign Trade and Growth-Suitcase Trading Connection

Directory of Open Access Journals (Sweden)

Sinem YAPAR SAÇIK

2013-12-01

Full Text Available Suitcase trading which is defined as a purchasing process of merchandises in a country that is implemented by travelers (nonresidents to sell those merchandises in their own country; it has started to take place in balance of payments of Turkey since 1996. After the collapse of USSR in 1991 Turkey became a net exporter in suitcase trading so the country reached significant figures occasionally. In this paper the position of suitcase trading in Turkey’s foreign trade is analyzed in consideration of statistical indicators. According to the findings acquired from the study, suitcase trading is a significant variable for Turkey to have currency and to close foreign deficits. Suitcase trading and growth connection is also analyzed by econometric method which is co-integration test and the result is affirmative. And also it is found that this connection is unilateral causation from growth towards suitcase trading according to the findings of Granger causality test

Multi-component wind measurements of wind turbine wakes performed with three LiDARs

Science.gov (United States)

Iungo, G. V.; Wu, Y.-T.; Porté-Agel, F.

2012-04-01

Field measurements of the wake flow produced from the interaction between atmospheric boundary layer and a wind turbine are performed with three wind LiDARs. The tested wind turbine is a 2 MW Enercon E-70 located in Collonges, Switzerland. First, accuracy of mean values and frequency resolution of the wind measurements are surveyed as a function of the number of laser rays emitted for each measurement. Indeed, measurements performed with one single ray allow maximizing sampling frequency, thus characterizing wake turbulence. On the other hand, if the number of emitted rays is increased accuracy of mean wind is increased due to the longer sampling period. Subsequently, two-dimensional measurements with a single LiDAR are carried out over vertical sections of the wind turbine wake and mean wake flow is obtained by averaging 2D measurements consecutively performed. The high spatial resolution of the used LiDAR allows characterizing in details velocity defect present in the central part of the wake and its downstream recovery. Single LiDAR measurements are also performed by staring the laser beam at fixed directions for a sampling period of about ten minutes and maximizing the sampling frequency in order to characterize wake turbulence. From these tests wind fluctuation peaks are detected in the wind turbine wake at blade top-tip height for different downstream locations. The magnitude of these turbulence peaks is generally reduced by moving downstream. This increased turbulence level at blade top-tip height observed for a real wind turbine has been already detected from previous wind tunnel tests and Large Eddy simulations, thus confirming the presence of a source of dangerous fatigue loads for following wind turbines within a wind farm. Furthermore, the proper characterization of wind fluctuations through LiDAR measurements is proved by the detection of the inertial subrange from spectral analysis of these velocity signals. Finally, simultaneous measurements with two

Wind Atlas for South Africa (WASA) Observational wind atlas for 10 met. stations in Northern, Western and Eastern Cape provinces

DEFF Research Database (Denmark)

Mortensen, Niels Gylling; Hansen, Jens Carsten; Kelly, Mark C.

As part of the “Wind Atlas for South Africa” project, microscale modelling has been carried out for 10 meteorological stations in Northern, Western and Eastern Cape provinces. Wind speed and direction data from the ten 60-m masts have been analysed using the Wind Atlas Analysis and Application...... Program (WAsP 11). The windclimatological inputs are the observed wind climates derived from the WAsP Climate Analyst. Topographical inputs are elevation maps constructed from SRTM 3 data and rough-ness length maps constructed from SWBD data and Google Earth satellite imagery. Summaries are given...... of the data measured at the 10 masts, mainly for a 3-year reference period from October 2010 to September 2013. The main result of the microscale modelling is observational wind atlas data sets, which can be used for verification of the mesoscale modelling. In addition, the microscale modelling itself has...

Livestock Disease Management for Trading Across Different Regulatory Regimes.

Science.gov (United States)

Bate, Andrew M; Jones, Glyn; Kleczkowski, Adam; Naylor, Rebecca; Timmis, Jon; White, Piran C L; Touza, Julia

2018-02-12

The maintenance of livestock health depends on the combined actions of many different actors, both within and across different regulatory frameworks. Prior work recognised that private risk management choices have the ability to reduce the spread of infection to trading partners. We evaluate the efficiency of farmers' alternative biosecurity choices in terms of their own-benefits from unilateral strategies and quantify the impact they may have in filtering the disease externality of trade. We use bovine viral diarrhoea (BVD) in England and Scotland as a case study, since this provides an example of a situation where contrasting strategies for BVD management occur between selling and purchasing farms. We use an agent-based bioeconomic model to assess the payoff dependence of farmers connected by trade but using different BVD management strategies. We compare three disease management actions: test-cull, test-cull with vaccination and vaccination alone. For a two-farm trading situation, all actions carried out by the selling farm provide substantial benefits to the purchasing farm in terms of disease avoided, with the greatest benefit resulting from test-culling with vaccination on the selling farm. Likewise, unilateral disease strategies by purchasers can be effective in reducing disease risks created through trade. We conclude that regulation needs to balance the trade-off between private gains from those bearing the disease management costs and the positive spillover effects on others.

Capacity expansion model of wind power generation based on ELCC

Science.gov (United States)

Yuan, Bo; Zong, Jin; Wu, Shengyu

2018-02-01

Capacity expansion is an indispensable prerequisite for power system planning and construction. A reasonable, efficient and accurate capacity expansion model (CEM) is crucial to power system planning. In most current CEMs, the capacity of wind power generation is considered as boundary conditions instead of decision variables, which may lead to curtailment or over construction of flexible resource, especially at a high renewable energy penetration scenario. This paper proposed a wind power generation capacity value(CV) calculation method based on effective load-carrying capability, and a CEM that co-optimizes wind power generation and conventional power sources. Wind power generation is considered as decision variable in this model, and the model can accurately reflect the uncertainty nature of wind power.

Microbiology of Wind-eroded Sediments: Current Knowledge and Future Research Directions

Science.gov (United States)

Wind erosion is a threat to the sustainability and productivity of soils that takes place at local, regional, and global scales. Current estimates of cost of wind erosion have not included the costs associated with the loss of soil biodiversity and reduced ecosystem functions. Microorganisms carrie...

Round-the-year security analysis with bottleneck ranking for interconnected power systems with large-scale wind power

NARCIS (Netherlands)

Ciupuliga, A.R.; Gibescu, M.; Pelgrum, E.; Jacobs, P.G.H.; Jansen, C.P.J.; Kling, W.L.

2010-01-01

The ongoing liberalization process in Europe together with the growing penetration of renewable energy sources (RES), e.g. wind power, require an internationally oriented transmission planning approach that considers the increased uncertainties in terms of trade, location of generation and output of

Applied modal analysis of wind turbine blades

DEFF Research Database (Denmark)

Pedersen, H.B.; Kristensen, O.J.D.

2003-01-01

In this project modal analysis has been used to determine the natural frequencies, damping and the mode shapes for wind turbine blades. Different methods to measure the position and adjust the direction of the measuring points are discussed. Differentequipment for mounting the accelerometers...... is investigated by repeated measurement on the same wind turbine blade. Furthermore the flexibility of the test set-up is investigated, by use ofaccelerometers mounted on the flexible adapter plate during the measurement campaign. One experimental campaign investigated the results obtained from a loaded...... and unloaded wind turbine blade. During this campaign the modal analysis are performed on ablade mounted in a horizontal and a vertical position respectively. Finally the results obtained from modal analysis carried out on a wind turbine blade are compared with results obtained from the Stig Øyes blade_EV1...

Measurement of the environmental noise at the Torseroed wind turbine site

International Nuclear Information System (INIS)

Fegeant, Olivier

2000-12-01

Further to complaints about the noise generated by a Micon 600 kW wind turbine, measurements of both noise immission and noise emission were performed at the Torseroed site. The measurements and analysis presented in this report were carried out by following the recommendations of the IEA documents for noise emission and immission measurements. It was found that the immission level, i.e. the wind turbine sound, at one of the nearest dwelling, namely Solglaentan, is 39 dB(A) for a wind speed of 8 m/s at hub height. Measurements carried out close to the turbine show that the sound power level of the turbine is 4.3 dB higher than the A-weighted level given by the supplier. Furthermore, the noise level increases more rapidly as a function of the wind speed than what is expected from the values furnished by the manufacturer. The measurements results also show that the background noise level is unusually low at Solglaentan

Distribution and provenance of wind-blown SE Pacific surface sediments

OpenAIRE

Saukel, C.; Lamy, F.; Stuut, J.B.W.; Tiedemann, R.; Vogt, C.

2011-01-01

The reconstruction of low-latitude ocean-atmosphere interactions is one of the major issues of (paleo-) environmental studies. The trade winds, extending over 20 degrees to 30 degrees of latitude in both hemispheres, between the subtropical highs and the intertropical convergence zone, are major components of the atmospheric circulation and little is known about their long-term variability on geological time-scales, in particular in the Pacific sector. We present the modern spatial pattern of...

New Solutions for Renewable Energy Trading

Directory of Open Access Journals (Sweden)

Władysław Mielczarski

2014-09-01

Full Text Available The paper presents one of the key problems in renewable energy trading. The support system for RES is operating on financial levels leaving to the RES producers decisions on the energy trade. However, the flawed legal regulations impose the obligations on Default Electricity Supplier (SzU1 to buy all RES production from the installations located in the areas of the SzU operation. Such legal provisions result in the additional burden on the SzU, which main duty is to provide electric energy to customers who do not want to enter competitive electricity markets. Additionally, over interpretation of the Energy Law provisions by the Energy Regulatory Authority (URE2, allowing the RES producers to trade a part of their production on electricity markets leaving the obligation on SzUs, has led to the speculative trade of renewable energy. Some RES producers sell the electricity produced in competitive markets during peak demand hours – usually working days from 7 a.m. to 8 p.m. – when the Power Exchange prices are significantly higher than the obligatory purchase price. When during off peak demand hours electricity prices in the Power Exchange are lower than the obligatory level, RES producers sell the electric energy to SzUs at the obligatory price, determined by the URE. Such an abuse of fair trade results in the additional income for the RES producers being burden on SzUs, which have to transfer such costs to energy endusers. The simulations, carried out for Poland indicate that the additional costs can count for about 200 mln zł per year.

Multiobjective Optimization Model for Wind Power Allocation

Directory of Open Access Journals (Sweden)

Juan Alemany

2017-01-01

Full Text Available There is an increasing need for the injection to the grid of renewable energy; therefore, to evaluate the optimal location of new renewable generation is an important task. The primary purpose of this work is to develop a multiobjective optimization model that permits finding multiple trade-off solutions for the location of new wind power resources. It is based on the augmented ε-constrained methodology. Two competitive objectives are considered: maximization of preexisting energy injection and maximization of new wind energy injection, both embedded, in the maximization of load supply. The results show that the location of new renewable generation units affects considerably the transmission network flows, the load supply, and the preexisting energy injection. Moreover, there are diverse opportunities to benefit the preexisting generation, contrarily to the expected effect where renewable generation displaces conventional power. The proposed methodology produces a diverse range of equivalent solutions, expanding and enriching the horizon of options and giving flexibility to the decision-making process.

The Spanish Wind Energy Situation and Comparison with Portugal and The Netherlands

International Nuclear Information System (INIS)

Varela, M.; Gonzalez, R.

1999-01-01

This report review the institutional and legal framework of wind energy in Spain as well as the current market situation, considering the geographical distribution of power, its past evolution, what are the Spanish foreseen wind power.... A review of main actor within the wind market: suppliers, promoters, administrative bodies, is also performed. The second part of the report carries out a comparison of the Spanish wind energy situation with the current conditions in Portugal and The Netherlands. These two countries present different levels of wind development with also different approaches to wind energy integration. Finally, the report states some differences and weak points comparing their wind energy situation with the Spanish one. (Author) 12 refs

The ASEAN Free Trade Agreement: impact on trade flows and external trade barriers

OpenAIRE

Hector Calvo-Pardo; Caroline Freund; Emanuel Ornelas

2009-01-01

Using detailed data on trade and tariffs from 1992-2007, the authors examine how the ASEAN Free Trade Agreement has affected trade with nonmembers and external tariffs facing nonmembers. First, the paper examines the effect of preferential and external tariff reduction on import growth from ASEAN insiders and outsiders across HS 6-digit industries. The analysis finds no evidence that prefe...

Effects of offshore wind energy developments on navigation and commercial shipping

Energy Technology Data Exchange (ETDEWEB)

Petts, J W

1999-07-01

This report summarises the findings of a study examining the impact of the development of offshore wind farms on commercial shipping and navigation in the area of the UK continental shelf. The study methodology is described, and a review of previous studies is carried out. Technological and current developments, wind farm layout and physical limitations, interaction with marine users, and a quantitative assessment are examined, and the protection of offshore wind farms is considered. Appendices give details of admiralty charts and publications, maps, and chart markings for wind turbines. (UK)

Advertising of slave trade in the Romanian principalities

Directory of Open Access Journals (Sweden)

Marian Petcu

2014-12-01

Full Text Available This study deals with the thorny issue of the history of our country – the Gypsy slave trade, as it was presented in the press (1837-1844. We have identified a number of advertisements that reflect the type of trade, its form, prices for slaves, and institutions involved in such transactions. All this information is presented in a variety of contexts: the writings of foreign travelers, responses of public authorities, official documents. Studied documents leave no doubt as to the intention of the authorities to assimilate the Gypsies. There is also highlighted the role of the press as an intermediary in the Gypsy slave trade. Since we are talking about semi-official publications (Cantor de Avis şi Comerţ, Vestitorul Românesc, Albina Românească, it should be understood that these transactions were carried out with the consent of the heads of the relevant state entities. The study also highlights the stages of freeing the slaves.

Comparative simulation of wind park design and siting in Algeria

International Nuclear Information System (INIS)

Youcef Ettoumi, Fatiha; Adane, Abd El Hamid; Benzaoui, Mohamed Lassaad; Bouzergui, Nabila

2008-01-01

In this paper, five typical regions of Algeria where wind is strong enough are selected. These regions usually intended for traditional agriculture are, centred around the towns of Guelma, El Oued, Tindouf, Touggourt and Tamanrasset. To make wind energy conversion available as an alternative energy source for the populations living in such countries, nine types of small and medium wind turbines constructed by American and European manufacturers are studied for their suitability. To account for the wind variations with height, four possible heights of the pylon holding the turbines are considered: 10, 20, 40 and 60 m. In each of the five locations and at each pylon height, wind energy converted by the turbines, is cumulated over the year and computed. Depending on the site and their size, most of these turbines are found to produce about 1000-10,000 MWh of electricity per year at 60 m of altitude and can easily satisfy the electricity need in irrigation and its household applications in rustic and arid regions. A quick glance of the results of the above computation shows that the choice of pylons of 20 m height yields a trade-off between the production of electrical energy and the requirements of economy. Owing to the sporadic wind variations, wind energy conversion systems can only be used as an auxiliary source. In particular, these systems can advantageously be coupled to stand-alone photovoltaic conversion systems in remote locations or connected to the electric mains in urban zones. (author)

Isolated systems with wind power. An implementation guideline

Energy Technology Data Exchange (ETDEWEB)

Clausen, N.E.; Bindner, H.; Frandsen, S.; Hansen, J.C.; Hansen, L.H.; Lundsager, P.

2001-06-01

The overall objective of this research project is to study the development of methods and guidelines rather than 'universal solutions' for the use of wind energy in isolated communities. So far most studies of isolated systems with wind power have been case-oriented and it has proven difficult to extend results from one project to another, not least due to the strong individuality that has characterised such systems in design and implementation. In the present report a unified and generally applicable approach is attempted in order to support a fair assessment of the technical and economical feasibility of isolated power supply systems with wind energy. General guidelines and checklists on which facts and data are needed to carry out a project feasibility analysis are presented as well as guidelines how to carry out the project feasibility study and the environmental analysis. The report outlines the results of the project as a set of proposed guidelines to be applied when developing a project containing an application of wind in an isolated power system. It is the author's hope that this will facilitate the development of projects and enhance electrification of small rural communities in developing countries. (au)

Diode Laser Assisted Filament Winding of Thermoplastic Matrix Composites

Directory of Open Access Journals (Sweden)

Claudia Prosperi

2010-01-01

Full Text Available A new consolidation method for the laser-assisted filament winding of thermoplastic prepregs is discussed: for the first time a diode laser is used, as well as long glass fiber reinforced polypropylene prepregs. A consolidation apparatus was built by means of a CNC motion table, a stepper motor and a simple tensioner. Preliminary tests were performed in a hoop winding configuration: only the winding speed was changed, and all the other process parameters (laser power, distance from the laser focus, consolidation force were kept constant. Small wound rings with an internal diameter of 25 mm were produced and compression tests were carried out to evaluate the composite agglomeration in dependence of the winding speed. At lower winding speeds, a stronginterpenetration of adjacent layers was observed.

The Spanish Wind Energy Situation and Comparison with Portugal and The Netherlands

Energy Technology Data Exchange (ETDEWEB)

Varela, M.; Gonzalez, R. [Ciemat. Madrid (Spain)

1999-05-01

This report review the institutional and legal framework of wind energy in Spain as well as the current market situation, considering the geographical distribution of power, its past evaluation, what are the spanish foreseen wind power. A review of main actor within the wind market: suppliers promoters, administrative bodies, is also performed. The second part of the report carries out a comparison of the Spanish wind energy situation with the current conditions in Portugal and The Netherlands. These two countries present different approaches to wind energy integration. Finally, the report states some differences and weak points comparing their wind energy situation with the Spanish one. (Author) 12 refs.

Location of Swedish wind power—Random or not? A quantitative analysis of differences in installed wind power capacity across Swedish municipalities

International Nuclear Information System (INIS)

Ek, Kristina; Persson, Lars; Johansson, Maria; Waldo, Åsa

2013-01-01

The amount of installed wind power varies significantly across municipalities although the financial support for wind power production and the technology available is identical in all Swedish municipalities. This study analyses how local differences between municipalities, such as local wind prerequisites and socioeconomic conditions, might explain the establishment of wind power. The analysis is carried out for a cross section of Swedish municipalities. The time periods before and after 2006 are analyzed separately; and results reveal that the factors affecting wind power establishments are different between the two periods. In the later time period we found a statistically significant positive relationship between good wind resources and the presence of wind power as well as with the amount of wind energy installed. This result is consistent with the idea that the first wind power investments in Sweden were highly affected by individual wind energy enthusiasts, while in the more recent large-scale investments market-based judgments about future profitability may have become increasingly important. In addition, previous experience seems to be a factor that in itself facilitates additional future wind power establishments, thereby pointing to the role of accumulated institutional capacity. - Highlights: ► Local differences in installed wind power capacity in Sweden is analysed. ► The amount of installed wind power capacity varies significantly in time and space. ► Results reveal different determinants of installed capacity before/after 2006. ► Good wind resources have become increasingly important over time. ► Previous experience of wind power has a positive impact on installed capacity

Trade Facilitation Provisions in Regional Trade Agreements: Discriminatory or Non-discriminatory?

Directory of Open Access Journals (Sweden)

Innwon Park

2016-12-01

Full Text Available The RTAs with trade facilitation provisions have been expected to generate a larger net trade-creating effect and complement the discriminatory feature of RTAs but have yet to be empirically proven. Recognizing the limitations of existing studies, we conducted a quantitative analysis on the effects of RTAs with and without trade facilitation provisions on both intra- and extra-bloc trade by using a modified gravity equation. We applied the Poisson Pseudo-Maximum Likelihood (PPML estimation with time varying exporter and importer fixed effect method to panel data consisting of 45,770 country pairs covering 170 countries for 2000-2010. We found that the trade facilitation provisions in existing RTAs are non-discriminatory by generating more intra- and extra-bloc trade in general. In particular, we found that the trade effects of RTAs in the APEC region are much stronger than the general case covering all RTAs in the world. In addition, as we control the trade effect of a country's trade facilitation, which is ranked by the World Bank's logistic performance index, RTAs consisting of trade facilitation provisions are discriminatory for trade in final goods and non-discriminatory for trade in intermediate goods. Overall, we endeavor to "explain," instead of "hypothesizing," why most of the recent RTAs contain trade facilitation provisions, especially in light of the deepening regional interdependence through trade in parts and components under global value chains and support the necessity of multilateralizing RTAs by implementing non-discriminatory trade facilitation provisions.

Wind energy options in the Netherlands

International Nuclear Information System (INIS)

Arkesteijn, L.A.G.; Havinga, R.J.

1992-07-01

Next to a study of the title subject attention is paid to the quantification of the wind energy potential and the conditions under which such potentials can be realized. The options are influenced by technical-economical, planning and socio-political factors, which are summarized in appendix 1 and discussed in chapter three. Results of interviews with experts in the field of wind energy can be found in appendix 2. Based on the impacts on the wind energy potential four wind energy development scenarios are compared in chapter four. The reference scenario is based on the present wind energy policy in the Netherlands. The other three scenarios are the Price-scenario (higher societal appreciation of electricity generated by wind power), the Site-scenario (matters of site selection and planning), and a Combined-scenario (combination of the Price- and the Site-scenario). For each scenario potential estimations were made for the years 2000, 2010, 2015, and restricted estimations for the year 2025. It is concluded that within 25 years 2,500 MW wind power can be realized on land and 6,000 MW on water. The main problems for the location on land and inland waterways are the planning restrictions, and for sea locations the limiting factor is the high cost price. Recommendations to the Dutch government to realize the potentials concern the facts that social advantages of wind energy should be part of the price of the energy, more sites should be made available for the application of wind energy, more research has to be carried out on the possibility of locating wind power generating systems at sea, and the social basis for wind energy should be maintained and even increased. 18 figs., 5 app., 47 refs

Economic optimization of offshore wind farms

International Nuclear Information System (INIS)

Pauling, T.

1996-09-01

The study on the title subject continues the development of a cost model for offshore wind farms started at the Institute for Wind Energy (IW) in 1995, and applies it on different kinds of cost analyses. The model will be considered within the European research project 'Structural and Economic Optimization of Bottom-Mounted Offshore Wind Energy Converters' (Opti-OWECS, JOR3-CT95-0087) co-ordinated by the IW, where also the cost analyses and optimization will be extended. The conclusions of the investigations have already been presented at the European Union Wind Energy Conference '96 at Goeteborg, Sweden. In Chapter 1, a short overview of former offshore studies and projects is given, especially those dealing with cost analysis. Typical cost breakdowns of offshore and onshore wind farms are compared. Chapter 2 contains a brief description of the cost model in its present state. The recent improvements and extensions are documented in Chapter 3, and a validation by means of a recalculation of two former offshore studies is carried out in Chapter 4. In Chapter 5, four different offshore sites are compared with respect to the same farm size and an optimized farm design: Jade in the German part of the North Sea near Wilhelmshafen; Swansea Bay in the Bristol Channel at the British Atlantic Coast; Rostock at the German Baltic Coast, and IJmuiden in the Dutch part of the North Sea. In Chapter 6, a sensitivity study is carried out for a variety of site, design and economical parameters. The results of this project are summarized in Chapter 7, and an outlook is given in Chapter 8. The appendix contains among others a description of the SCOptiM2 code, where the model is implemented, as well as data obtained from the parameter studies and design optimizations. 30 figs., 8 tabs., 6 appendices, 40 refs

Pitch Angle Control for Variable Speed Wind Turbines

DEFF Research Database (Denmark)

Chen, Zhe; Zhang, Jianzhong; Cheng, M

2008-01-01

Pitch angle control is the most common means for adjusting the aerodynamic torque of the wind turbine when wind speed is above rated speed and various controlling variables may be chosen, such as wind speed, generator speed and generator power. As conventional pitch control usually use PI...... controller, the mathematical model of the system should be known well. A fuzzy logic pitch angle controller is developed in this paper, in which it does not need well known about the system and the mean wind speed is used to compensate the non-linear sensitivity. The fuzzy logic control strategy may have...... the potential when the system contains strong non-linearity, such as wind turbulence is strong, or the control objectives include fatigue loads. The design of the fuzzy logic controller and the comparisons with conversional pitch angle control strategies with various controlling variables are carried out...

Optimization design of blade shapes for wind turbines

DEFF Research Database (Denmark)

Chen, Jin; Wang, Xudong; Shen, Wen Zhong

2010-01-01

For the optimization design of wind turbines, the new normal and tangential induced factors of wind turbines are given considering the tip loss of the normal and tangential forces based on the blade element momentum theory and traditional aerodynamic model. The cost model of the wind turbines...... and the optimization design model are developed. In the optimization model, the objective is the minimum cost of energy and the design variables are the chord length, twist angle and the relative thickness. Finally, the optimization is carried out for a 2 MW blade by using this optimization design model....... The performance of blades is validated through the comparison and analysis of the results. The reduced cost shows that the optimization model is good enough for the design of wind turbines. The results give a proof for the design and research on the blades of large scale wind turbines and also establish...

Analysis of the potential for wind energy production in northwestern Ontario

Energy Technology Data Exchange (ETDEWEB)

Brown, C K; Warne, D F

1975-11-01

A study of the feasibility of generating electric power from wind generators at remote sites in Northwestern Ontario has been carried out on behalf of the Ontario Ministry of Energy, with project management from Ontario Hydro. The work included (1) a survey of commercially available wind driven electric plant, both currently available and planned for production, (2) an analysis of existing wind data and preparation of an isovent map for Ontario showing annual mean wind speeds, (3) the selection of suitable sites for a demonstration unit and a prototype system, (4) the matching of available plant to the wind regimes to predict annual energy production, and (5) a systems analysis of pure diesel, hybrid wind/diesel and pure wind electric plants to determine the cost of power from the various alternatives.

Research in wind pumping, so what?

International Nuclear Information System (INIS)

Smulders, P.T.; Diepens, J.F.L.

1991-01-01

The three main objectives of the Consultancy Services Wind Energy in Developing Countries (CWD), R ampersand D, transfer of know-how and windmill projects, are explained. During its existence (1975-1990), the CWD has carried out research on rotors, safety systems, transmissions, system behaviour and testing. R ampersand D is still important to reduce investment costs, to improve the efficiency and reliability, and to reduce the operation and maintenance costs. Examples are given of innovative projects: the so-called matching valve and hydraulic sealing. The advantages of the first are more water output, especially at a low wind speed (no hysteresis) and a less critical matching to the wind regime. Hydraulic seals make it possible to reduce the maintenance needs. It replaces the traditional leather cups. 4 figs., 1 tab., 1 app., 1 ref

Wind farm balance of plant costs

International Nuclear Information System (INIS)

Craig, L.; Liebmann, C.

1992-01-01

The study consisted of a detailed investigation of the infrastructure required for the construction and operation of a windfarm in the UK. Costing of the equipment and installation was carried out for three UK sites, with different physical characteristics. A literature survey was carried out to determine current practice in the siting of turbines within windfarms in Europe and the USA. Wind turbines were then laid out on the sites selected for study. Requirements and costs for roads, foundations and site buildings, site electrical system and grid connection, the supervisory control and data acquisition system were discussed and evaluated. A comparison between the balance of plant costs for the 33-metre MS-3 400 kW wind turbine and the 50-metre LS-2 1 MW wind turbine was made for each area of study. Overall balance of plant costs was reviewed, with an investigation of the cost components which are most sensitive to variations. The balance of plant costs averaged over the three sites were 13.0 p/kWh/annum for the MS3 windfarms and 10.6 p/kWh/annum for the LS-2 windfarms. Maps of the sites under investigation, design drawings and tables of costs are included to give supporting information to the text. (author)

Can a wind farm with CAES survive in the day-ahead market?

International Nuclear Information System (INIS)

Mauch, Brandon; Carvalho, Pedro M.S.; Apt, Jay

2012-01-01

We investigate the economic viability of coupling a wind farm with compressed air energy storage (CAES) to participate in the day-ahead electricity market at a time when renewable portfolio standards are not binding and wind competes freely in the marketplace. In our model, the CAES is used to reduce the risk of committing uncertain quantities of wind energy and to shift dispatch of wind generation to high price periods. Other sources of revenue (capacity markets, ancillary services, price arbitrage) are not included in the analysis. We present a model to calculate profit maximizing day-ahead dispatch schedules based on wind forecasts. Annual profits are determined with dispatch schedules and actual wind generation values. We find that annual income for the modeled wind–CAES system would not cover annualized capital costs using market prices from the years 2006 to 2009. We also estimate market prices with a carbon price of $20 and $50 per tonne CO 2 and find that revenue would still not cover the capital costs. The implied cost per tonne of avoided CO 2 to make a wind–CAES profitable from trading on the day-ahead market is roughly $100, with large variability due to electric power prices. - Highlights: ► We modeled a wind farm participating in the day-ahead electricity market. ► We calculated optimal day-ahead market offers based on wind forecasts. ► Revenue is then calculated using measured wind power. ► We find that revenue is insufficient to cover capital costs at current market prices.

Design of wind turbines. What does the public like?

International Nuclear Information System (INIS)

Geuzendam, C.; Uitzinger, J.

1997-01-01

Fifteen wind turbine designs are assessed by the public. The study was carried out by means of a face-to-face survey among 76 occupants of the municipalities Schagen (western part of the Netherlands) and Zutphen (eastern part of the Netherlands). Use has been made of illustrations of the 15 different wind turbine types and four different types of landscapes. The illustrations are included in this report

Wind power forecasting accuracy and uncertainty in Finland

Energy Technology Data Exchange (ETDEWEB)

Holttinen, H.; Miettinen, J.; Sillanpaeae, S.

2013-04-15

Wind power cannot be dispatched so the production levels need to be forecasted for electricity market trading. Lower prediction errors mean lower regulation balancing costs, since relatively less energy needs to go through balance settlement. From the power system operator point of view, wind power forecast errors will impact the system net imbalances when the share of wind power increases, and more accurate forecasts mean less regulating capacity will be activated from the real time Regulating Power Market. In this publication short term forecasting of wind power is studied mainly from a wind power producer point of view. The forecast errors and imbalance costs from the day-ahead Nordic electricity markets are calculated based on real data from distributed wind power plants. Improvements to forecasting accuracy are presented using several wind forecast providers, and measures for uncertainty of the forecast are presented. Aggregation of sites lowers relative share of prediction errors considerably, up to 60%. The balancing costs were also reduced up to 60%, from 3 euro/MWh for one site to 1-1.4 euro/MWh to aggregate 24 sites. Pooling wind power production for balance settlement will be very beneficial, and larger producers who can have sites from larger geographical area will benefit in lower imbalance costs. The aggregation benefits were already significant for smaller areas, resulting in 30-40% decrease in forecast errors and 13-36% decrease in unit balancing costs, depending on the year. The resulting costs are strongly dependent on Regulating Market prices that determine the prices for the imbalances. Similar level of forecast errors resulted in 40% higher imbalance costs for 2012 compared with 2011. Combining wind forecasts from different Numerical Weather Prediction providers was studied with different combination methods for 6 sites. Averaging different providers' forecasts will lower the forecast errors by 6% for day-ahead purposes. When combining

The Supply of Trade Credit by Brazilian Publicly Traded Firms

Directory of Open Access Journals (Sweden)

Rafael Felipe Schiozer

2011-12-01

Full Text Available This paper investigates the determinants of trade credit supply by Brazilian publicly traded companies between the years of 2005 and 2008. International literature (both theoretical and empirical documents that the main determinants of trade credit supply are the size of the firm and the size of its debt. Both indicate that the availability of resources to the firm is an important factor for the supply of trade credit. In addition, the literature confirms strategic uses of trade credit such as those for price discrimination purposes. The results obtained using a sample of 157 Brazilian companies do not support that size and indebtedness are relevant determinants for trade credit supply, but they confirm the supply of trade credit as a strategic tool for the firms. Additionally we observed a significant decrease in trade credit supply in 2008, the year in which a severe international financial crisis took place.

Progressive innovations in applying of wind energy

International Nuclear Information System (INIS)

Yershina, Ainakul K.; Yershin, Chingiz Sh.

2013-01-01

The article presents the current design of a laboratory model, the so-called model of vertical-axis wind turbine component. Construction work carried out, and then made a valid laboratory model of cross-sectional area S = 0,64 m 2 , which can operate as a conventional Darya, and in the mode of our constructive solutions. The tower that supports the wind turbine installed in the vertical position of the shaft 2, each of which is connected with only one blade and working with their current generator. The shafts are separated by a bearing and can operate autonomously, independently of each other. The mechanical energy of rotation is transferred to two different power generators, ie Each shaft works on his generator. Electricity generated by them is summarized. Thus, the feature of this design is the increased removal of wind energy in two independent working trees with the same swept area. Therefore, effective value of wind energy usage efficiency may be increased to 0.7 in case of high production culture.Vertical - axis turbine component has a special lock that supports the angle between the furs 180 °. Key words: wind turbine Darrieus, shaft, generator current, power, wind speed, blade

Progressive innovations in applying of wind energy

Energy Technology Data Exchange (ETDEWEB)

Yershina, Ainakul K. [Kazakh State Women Pedogogical University, Almaty (Kazakhstan); Yershin, Chingiz Sh. [Kazakh Natio nal University named by al - Farabi, Almaty (Kazakhstan)

2013-07-01

The article presents the current design of a laboratory model, the so-called model of vertical-axis wind turbine component. Construction work carried out, and then made a valid laboratory model of cross-sectional area S = 0,64 m{sup 2} , which can operate as a conventional Darya, and in the mode of our constructive solutions. The tower that supports the wind turbine installed in the vertical position of the shaft 2, each of which is connected with only one blade and working with their current generator. The shafts are separated by a bearing and can operate autonomously, independently of each other. The mechanical energy of rotation is transferred to two different power generators, ie Each shaft works on his generator. Electricity generated by them is summarized. Thus, the feature of this design is the increased removal of wind energy in two independent working trees with the same swept area. Therefore, effective value of wind energy usage efficiency may be increased to 0.7 in case of high production culture.Vertical - axis turbine component has a special lock that supports the angle between the furs 180 °. Key words: wind turbine Darrieus, shaft, generator current, power, wind speed, blade.

77 FR 5865 - American Unity Investments, Inc., China Display Technologies, Inc., China Wind Energy, Inc., Fuda...

Science.gov (United States)

2012-02-06

... Display Technologies, Inc., China Wind Energy, Inc., Fuda Faucet Works, Inc., Greater China Media & Entertainment Corp., and Xechem International, Inc.; Order of Suspension of Trading February 2, 2012. It appears... Technologies, Inc. because it has not filed any periodic reports since the period ended September 30, 2008. It...

75 FR 23263 - Alta Wind I, LLC; Alta Wind II, LLC; Alta Wind III, LLC; Alta Wind IV, LLC; Alta Wind V, LLC...

Science.gov (United States)

2010-05-03

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. EL10-62-000] Alta Wind I, LLC; Alta Wind II, LLC; Alta Wind III, LLC; Alta Wind IV, LLC; Alta Wind V, LLC; Alta Wind VI, LLC; Alta Wind VII, LLC; Alta Wind VIII, LLC; Alta Windpower Development, LLC; TGP Development Company, LLC...