Sample records for cell power generation

  1. Scheduling of Power System Cells Integrating Stochastic Power Generation

    Energy supply and climate change are nowadays two of the most outstanding problems which societies have to cope with under a context of increasing energy needs. Public awareness of these problems is driving political willingness to take actions for tackling them in a swift and efficient manner. Such actions mainly focus in increasing energy efficiency, in decreasing dependence on fossil fuels, and in reducing greenhouse gas emissions. In this context, power systems are undergoing important changes in the way they are planned and managed. On the one hand, vertically integrated structures are being replaced by market structures in which power systems are un-bundled. On the other, power systems that once relied on large power generation facilities are witnessing the end of these facilities' life-cycle and, consequently, their decommissioning. The role of distributed energy resources such as wind and solar power generators is becoming increasingly important in this context. However, the large-scale integration of such type of generation presents many challenges due, for instance, to the uncertainty associated to the variability of their production. Nevertheless, advanced forecasting tools may be combined with more controllable elements such as energy storage devices, gas turbines, and controllable loads to form systems that aim to reduce the impacts that may be caused by these uncertainties. This thesis addresses the management under market conditions of these types of systems that act like independent societies and which are herewith named power system cells. From the available literature, a unified view of power system scheduling problems is also proposed as a first step for managing sets of power system cells in a multi-cell management framework. Then, methodologies for performing the optimal day-ahead scheduling of single power system cells are proposed, discussed and evaluated under both a deterministic and a stochastic framework that directly integrates the

  2. AC power generation from microbial fuel cells

    Lobo, Fernanda Leite; Wang, Heming; Forrestal, Casey; Ren, Zhiyong Jason


    Microbial fuel cells (MFCs) directly convert biodegradable substrates to electricity and carry good potential for energy-positive wastewater treatment. However, the low and direct current (DC) output from MFC is not usable for general electronics except small sensors, yet commercial DC-AC converters or inverters used in solar systems cannot be directly applied to MFCs. This study presents a new DC-AC converter system for MFCs that can generate alternating voltage in any desired frequency. Results show that AC power can be easily achieved in three different frequencies tested (1, 10, 60 Hz), and no energy storage layer such as capacitors was needed. The DC-AC converter efficiency was higher than 95% when powered by either individual MFCs or simple MFC stacks. Total harmonic distortion (THD) was used to investigate the quality of the energy, and it showed that the energy could be directly usable for linear electronic loads. This study shows that through electrical conversion MFCs can be potentially used in household electronics for decentralized off-grid communities.

  3. Fuel cells for electric power generation

    After having first briefly illustrated the basic design, construction and operating principles of fuel cells, this paper assesses the progress that has been achieved to date in the development of the phosphoric acid (PAFC), molten carbonate (MCFC) and solid oxide (SOFC) fuel cells. Special attention is given to the design, performance and cost characteristics of the phosphoric acid fuel cells. For example, the paper cites the IFC/Toshiba 4.8 and 11.0 MW models, which have attained efficiencies of 37.5 and 41.0% respectively, and points out that these fuel cells, with efficiencies comparable to those of conventional poly-fuelled and combined cycle power plants, offer the advantages of compact size and better environmental compatibility with respect to the latter. However, fuel cells cannot yet compete with the lower per kWh costs of fossil fuel power plants. The paper concludes with an assessment of Italian fuel cell commercialization efforts, especially those centered around the use of methane fuelled PAFC's, and reviews the status of coordinated international research programs involving Japan, the USA and Italy

  4. Fuel cells make gains in power generation market

    The ultra-low emission, highly efficient natural gas-fueled fuel cell system is beginning to penetrate the electric power generation market in the US and abroad as the fuel cell industry lowers product costs. And, even as the current market continues to grow, fuel cell companies are developing new technology with even higher levels of energy efficiency. The paper discusses fuel cell efficiency, business opportunities, work to reduce costs, and evolving fuel cell technology

  5. Intelligent Power Management of hybrid Wind/ Fuel Cell/ Energy Storage Power Generation System

    A. Hajizadeh; Hassanzadeh, F.


    This paper presents an intelligent power management strategy for hybrid wind/ fuel cell/ energy storage power generation system. The dynamic models of wind turbine, fuel cell and energy storage have been used for simulation of hybrid power system. In order to design power flow control strategy, a fuzzy logic control has been implemented to manage the power between power sources. The optimal operation of the hybrid power system is a main goal of designing power management strategy. The hybrid ...

  6. Power generation properties of Direct Flame Fuel Cell (DFFC)

    This paper investigated the effect of cell temperature and product species concentration induced by small-jet flame on the power generation performance of Direct Flame Fuel Cell (DFFC). The cell is placed above the small flame and heated product gas is impinged toward it and this system is the simplest and smallest unit of the power generation device to be developed. Equivalence ratio (φ) and the distance between the cell and the burner surface (d) are considered as main experimental parameters. It turns out that open circuit voltage (OCV) increases linearly with the increase of temperature in wide range of equivalence ratios. However, it increases drastically at which the equivalence ratio became small (φ ≤ 2.0) showing inner flame clearly. This result suggests that OCV depends on not only cell temperature but also the species concentration exposed to the cell. It is suggested that Nernst equation might work satisfactory to predict OCV of DFFC

  7. Intelligent Power Management of hybrid Wind/ Fuel Cell/ Energy Storage Power Generation System

    A. Hajizadeh


    Full Text Available This paper presents an intelligent power management strategy for hybrid wind/ fuel cell/ energy storage power generation system. The dynamic models of wind turbine, fuel cell and energy storage have been used for simulation of hybrid power system. In order to design power flow control strategy, a fuzzy logic control has been implemented to manage the power between power sources. The optimal operation of the hybrid power system is a main goal of designing power management strategy. The hybrid power system is simulated in MATLAB/ SIMIULINK environment and different operating conditions have been considered to evaluate the response of power management strategy.

  8. Novel power electronic interface for grid-connected fuel cell power generation system

    Highlights: • A fuel cell power generation system was composed of a DC–DC power converter and a DC–AC inverter. • A voltage doubler based topology was adopted to configure the DC–DC power converter. • A dual buck power converter and a full-bridge power converter were applied to the DC–AC inverter. • The DC–AC inverter outputs a five-level voltage. • The DC–AC inverter performs the functions of DC–AC power conversion and active power filter. - Abstract: A novel power electronic interface for the grid-connected fuel cell power generation system is proposed in this paper. This power electronic interface is composed of a DC–DC power converter and a DC–AC inverter. A voltage doubler based topology is adopted to configure the DC–DC power converter to perform high step-up gain for boosting the output voltage of the fuel cell to a higher voltage. Moreover, the input current ripple of the fuel cell is suppressed by controlling the DC–DC power converter. The DC–AC inverter is configured by a dual buck power converter and a full-bridge power converter to generate a five-level AC output voltage. The DC–AC inverter can perform the functions of DC–AC power conversion and active power filtration. A 1.2 kW hardware prototype is developed to verify the performance of the proposed power electronic interface for the grid-connected fuel cell power generation system. The experimental results show that the proposed power electronic interface for the grid-connected fuel cell power generation system has the expected performance

  9. Fuel cell - An alternative for power and heat generating

    One of the most promising energy generating technologies is the fuel cell (FC) because of its high efficiency and low emissions. There are even zero chemical emissions FC and cogeneration plants based on FC generate low heat emissions too. FC was invented 160 years ago but it was usually used only since 1960 in space missions. A FC farm tractor was tested 40 years ago. FC was again taken into account by power engineering since 1990 and it is now considered a credible alternative to power and heat generating. The thermal power engineers (and not only they) have two problems of cardinal importance for mankind to solve: - Energy saving (by increasing of energy generating efficiency) and - Environmental protection (by reducing chemical and heat emissions). The possibilities to use FC to generate power and heat are practically endless: on the earth, in the air and outer space, by and under water, in numberless areas of human activities. FC are now powering buses, cars, trains, boats, plains, scooters, highway road signs etc. There are already miniature FC for portable electronics. Homes, schools, hospitals, institutes, banks, police stations, etc are using FC to generate power and heat for their facilities. The methane gas produced by wastewater treatment plants and landfills is converted into electricity by using FC. Being less expensive than nuclear and solar source of energy, FC is now generally used in the space missions (in addition FC generates water). In this work an analysis of the possibilities to use FC especially for combined power and heat generating is presented. FC is favourite as energy source in space missions because it is less expensive than nuclear or solar sources. All major automobile companies have FC powered automobiles in testing stage. Mini FC for phone, laptop, and electronics are already on market. FC will be use to pagers, video recorders, small portable tools, miniature robots, special devices as hearing aid various devices, smoke detectors

  10. Copper anode corrosion affects power generation in microbial fuel cells

    Zhu, Xiuping


    Non-corrosive, carbon-based materials are usually used as anodes in microbial fuel cells (MFCs). In some cases, however, metals have been used that can corrode (e.g. copper) or that are corrosion resistant (e.g. stainless steel, SS). Corrosion could increase current through galvanic (abiotic) current production or by increasing exposed surface area, or decrease current due to generation of toxic products from corrosion. In order to directly examine the effects of using corrodible metal anodes, MFCs with Cu were compared with reactors using SS and carbon cloth anodes. MFCs with Cu anodes initially showed high current generation similar to abiotic controls, but subsequently they produced little power (2 mW m-2). Higher power was produced with microbes using SS (12 mW m-2) or carbon cloth (880 mW m-2) anodes, with no power generated by abiotic controls. These results demonstrate that copper is an unsuitable anode material, due to corrosion and likely copper toxicity to microorganisms. © 2013 Society of Chemical Industry.

  11. Power generation from furfural using the microbial fuel cell

    Luo, Yong; Liu, Guangli; Zhang, Renduo; Zhang, Cuiping [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, Guangdong 510275 (China)


    Furfural is a typical inhibitor in the ethanol fermentation process using lignocellulosic hydrolysates as raw materials. In the literature, no report has shown that furfural can be utilized as the fuel to produce electricity in the microbial fuel cell (MFC), a device that uses microbes to convert organic compounds to generate electricity. In this study, we demonstrated that electricity was successfully generated using furfural as the sole fuel in both the ferricyanide-cathode MFC and the air-cathode MFC. In the ferricyanide-cathode MFC, the maximum power densities reached 45.4, 81.4, and 103 W m{sup -3}, respectively, when 1000 mg L{sup -1} glucose, a mixture of 200 mg L{sup -1} glucose and 5 mM furfural, and 6.68 mM furfural were used as the fuels in the anode solution. The corresponding Coulombic efficiencies (CE) were 4.0, 7.1, and 10.2% for the three treatments, respectively. For pure furfural as the fuel, the removal efficiency of furfural reached up to 95% within 12 h. In the air-cathode MFC using 6.68 mM furfural as the fuel, the maximum values of power density and CE were 361 mW m{sup -2} (18 W m{sup -3}) and 30.3%, respectively, and the COD removal was about 68% at the end of the experiment (about 30 h). Increase in furfural concentrations from 6.68 to 20 mM resulted in increase in the maximum power densities from 361 to 368 mW m{sup -2}, and decrease in CEs from 30.3 to 20.6%. These results indicated that some toxic and biorefractory organics such as furfural might still be suitable resources for electricity generation using the MFC technology. (author)

  12. Power generation

    In the second half of twentieth century, nuclear power became an industrial reality. Now the operating 433 power plants, the 37 plants under construction, near 9000 years/reactor with only one serious accident with emission of radioactive material to the environment (Chernobyl) show the maturity of this technology. Today nuclear power contribute a 17% to the global generation and an increase of 75 % of the demand of electricity is estimated for 2020 while this demand is expected to triplicate by 2050. How this requirement can be satisfied? All the indicators seems to demonstrate that nuclear power will be the solution because of the shortage of other sources, the increase of the prices of the non renewable fuels and the scarce contribution of the renewable ones. In addition, the climatic changes produced by the greenhouse effect make even more attractive nuclear power. The situation of Argentina is analyzed and compared with other countries. The convenience of an increase of nuclear power contribution to the total national generation seems clear and the conclusion of the construction of the Atucha II nuclear power plant is recommended

  13. Fuel-cell based power generating system having power conditioning apparatus

    Mazumder, Sudip K.; Pradhan, Sanjaya K.


    A power conditioner includes power converters for supplying power to a load, a set of selection switches corresponding to the power converters for selectively connecting the fuel-cell stack to the power converters, and another set of selection switches corresponding to the power converters for selectively connecting the battery to the power converters. The power conveners output combined power that substantially optimally meets a present demand of the load.

  14. Direct power generation from waste coffee grounds in a biomass fuel cell

    Jang, Hansaem; Ocon, Joey D.; Lee, Seunghwa; Lee, Jae Kwang; Lee, Jaeyoung


    We demonstrate the possibility of direct power generation from waste coffee grounds (WCG) via high-temperature carbon fuel cell technology. At 900 °C, the WCG-powered fuel cell exhibits a maximum power density that is twice than carbon black. Our results suggest that the heteroatoms and hydrogen contained in WCG are crucial in providing good cell performance due to its in-situ gasification, without any need for pre-reforming. As a first report on the use of coffee as a carbon-neutral fuel, this study shows the potential of waste biomass (e.g. WCG) in sustainable electricity generation in fuel cells.

  15. Binary co-generation power plant with night-temperature (SOFC) fuel cells of natural gas, v. 15(57)

    Binary co-generation power plant with height-temperature SOFC fuel cells of natural gas are presented in this paper. Based on before optimization calculations for this type of power plants is made: basic measures, number of modules, electric power and fuel cell efficiency; gas turbine electric power and efficiency; co-generation steam turbine electric and heat power efficiency. Compare analysis of binary co-generation power plant with SOFC fuel cells and co-generative power plant without fuel cells in relation of efficiency, ecological benefits and profitability (economy analysis) is given. (Author)

  16. Optimal design of PEM fuel cells to generate maximum power: A CFD study

    Maher A.R. Sadiq Al-Baghdadi


    Full Text Available A full three-dimensional, multi-phase computational fluid dynamics model of a PEM fuel cell has been developed. The parametric study using this model has been performed and discussed in detail. Optimization study of a PEM fuel cell performance has been performed. The study quantifies and analyses the impact of operating, design, and material parameters on fuel cell performance and get an optimal design for PEM fuel cells to generate maximum power. To generate maximum power, the results show that the cell must be operate at higher cell operating temperature, higher cell operating pressure, higher stoichiometric flow ratio, and must have higher GDL porosity, higher GDL thermal conductivity, narrower gases channels, and thinner membrane. At these optimum conditions, the result shows that the total displacement and the degree of the deformation inside the MEA were decreased. However, the Miss stress in the membrane was increased due to higher cell operating temperature.

  17. Cochlear Outer-Hair-Cell Power Generation and Viscous Fluid Loss

    Yanli Wang; Steele, Charles R.; Sunil Puria


    Since the discovery of otoacoustic emissions and outer hair cell (OHC) motility, the fundamental question of whether the cochlea produces mechanical power remains controversial. In the present work, direct calculations are performed on power loss due to fluid viscosity and power generated by the OHCs. A three-dimensional box model of the mouse cochlea is used with a feed-forward/feed-backward approximation representing the organ of Corti cytoarchitecture. The model is fit to in vivo basilar m...

  18. Electric power generation. Thermal power generating systems

    This is a manuscript for a lecture contents: 1) Steam power and fundamentals of the steam power process, 3) conventional, nuclear and other steam generation processes, 4) cooling systems for steam power plants, 5) gas turbine power plants and combined-cycle power plants, 6) cogeneration, 7) development of thermal power plants and environmental effects. (GL)

  19. Major design issues of molten carbonate fuel cell power generation unit

    Chen, T.P.


    In addition to the stack, a fuel cell power generation unit requires fuel desulfurization and reforming, fuel and oxidant preheating, process heat removal, waste heat recovery, steam generation, oxidant supply, power conditioning, water supply and treatment, purge gas supply, instrument air supply, and system control. These support facilities add considerable cost and system complexity. Bechtel, as a system integrator of M-C Power`s molten carbonate fuel cell development team, has spent substantial effort to simplify and minimize these supporting facilities to meet cost and reliability goals for commercialization. Similiar to other fuels cells, MCFC faces design challenge of how to comply with codes and standards, achieve high efficiency and part load performance, and meanwhile minimize utility requirements, weight, plot area, and cost. However, MCFC has several unique design issues due to its high operating temperature, use of molten electrolyte, and the requirement of CO2 recycle.

  20. A polymer electrolyte fuel cell stack for stationary power generation from hydrogen fuel

    Zawodzinski, C.; Wilson, M.; Gottesfeld, S. [Los Alamos National Lab., NM (United States)


    The fuel cell is the most efficient device for the conversion of hydrogen fuel to electric power. As such, the fuel cell represents a key element in efforts to demonstrate and implement hydrogen fuel utilization for electric power generation. A central objective of a LANL/Industry collaborative effort supported by the Hydrogen Program is to integrate PEM fuel cell and novel stack designs at LANL with stack technology of H-Power Corporation (H-Power) in order to develop a manufacturable, low-cost/high-performance hydrogen/air fuel cell stack for stationary generation of electric power. A LANL/H-Power CRADA includes Tasks ranging from exchange, testing and optimization of membrane-electrode assemblies of large areas, development and demonstration of manufacturable flow field, backing and bipolar plate components, and testing of stacks at the 3-5 cell level and, finally, at the 4-5 kW level. The stack should demonstrate the basic features of manufacturability, overall low cost and high energy conversion efficiency. Plans for future work are to continue the CRADA work along the time line defined in a two-year program, to continue the LANL activities of developing and testing stainless steel hardware for longer term stability including testing in a stack, and to further enhance air cathode performance to achieve higher energy conversion efficiencies as required for stationary power application.

  1. A polymer electrolyte fuel cell stack for stationary power generation from hydrogen fuel

    Gottesfeld, S. [Los Alamos National Lab., NM (United States)


    The fuel cell is the most efficient device for the conversion of hydrogen fuel to electric power. As such, the fuel cell represents a key element in efforts to demonstrate and implement hydrogen fuel utilization for electric power generation. The low temperature, polymer electrolyte membrane fuel cell (PEMFC) has recently been identified as an attractive option for stationary power generation, based on the relatively simple and benign materials employed, the zero-emission character of the device, and the expected high power density, high reliability and low cost. However, a PEMFC stack fueled by hydrogen with the combined properties of low cost, high performance and high reliability has not yet been demonstrated. Demonstration of such a stack will remove a significant barrier to implementation of this advanced technology for electric power generation from hydrogen. Work done in the past at LANL on the development of components and materials, particularly on advanced membrane/electrode assemblies (MEAs), has contributed significantly to the capability to demonstrate in the foreseeable future a PEMFC stack with the combined characteristics described above. A joint effort between LANL and an industrial stack manufacturer will result in the demonstration of such a fuel cell stack for stationary power generation. The stack could operate on hydrogen fuel derived from either natural gas or from renewable sources. The technical plan includes collaboration with a stack manufacturer (CRADA). It stresses the special requirements from a PEMFC in stationary power generation, particularly maximization of the energy conversion efficiency, extension of useful life to the 10 hours time scale and tolerance to impurities from the reforming of natural gas.

  2. Hydrogen Fuel Cell Analysis: Lessons Learned from Stationary Power Generation Final Report

    Scott E. Grasman; John W. Sheffield; Fatih Dogan; Sunggyu Lee; Umit O. Koylu; Angie Rolufs


    This study considered opportunities for hydrogen in stationary applications in order to make recommendations related to RD&D strategies that incorporate lessons learned and best practices from relevant national and international stationary power efforts, as well as cost and environmental modeling of pathways. The study analyzed the different strategies utilized in power generation systems and identified the different challenges and opportunities for producing and using hydrogen as an energy carrier. Specific objectives included both a synopsis/critical analysis of lessons learned from previous stationary power programs and recommendations for a strategy for hydrogen infrastructure deployment. This strategy incorporates all hydrogen pathways and a combination of distributed power generating stations, and provides an overview of stationary power markets, benefits of hydrogen-based stationary power systems, and competitive and technological challenges. The motivation for this project was to identify the lessons learned from prior stationary power programs, including the most significant obstacles, how these obstacles have been approached, outcomes of the programs, and how this information can be used by the Hydrogen, Fuel Cells & Infrastructure Technologies Program to meet program objectives primarily related to hydrogen pathway technologies (production, storage, and delivery) and implementation of fuel cell technologies for distributed stationary power. In addition, the lessons learned address environmental and safety concerns, including codes and standards, and education of key stakeholders.

  3. Characterization of a microfluidic microbial fuel cell as a power generator based on a nickel electrode.

    Mardanpour, Mohammad Mahdi; Yaghmaei, Soheila


    This study reports the fabrication of a microfluidic microbial fuel cell (MFC) using nickel as a novel alternative for conventional electrodes and a non-phatogenic strain of Escherichia coli as the biocatalyst. The feasibility of a microfluidic MFC as an efficient power generator for production of bioelectricity from glucose and urea as organic substrates in human blood and urine for implantable medical devices (IMDs) was investigated. A maximum open circuit potential of 459 mV was achieved for the batch-fed microfluidic MFC. During continuous mode operation, a maximum power density of 104 Wm(-3) was obtained with nutrient broth. For the glucose-fed microfluidic MFC, the maximum power density of 5.2 μW cm(-2) obtained in this study is significantly greater than the power densities reported previously for microsized MFCs and glucose fuel cells. The maximum power density of 14 Wm(-3) obtained using urea indicates the successful performance of a microfluidic MFC using human excreta. It features high power density, self-regeneration, waste management and a low production cost (<$1), which suggest it as a promising alternative to conventional power supplies for IMDs. The performance of the microfluidic MFC as a power supply was characterized based on polarization behavior and cell potential in different substrates, operational modes, and concentrations. PMID:26720922

  4. Power generation performance of direct flame fuel cell (DFFC) impinged by small jet flames

    Nakamura, Yuji; Endo, Shota


    This paper investigated the effect of cell temperature and product species concentration induced by a small jet flame on the power generation performance of a direct flame fuel cell (DFFC). The cell is placed above the small-scale jet flame and the heated product’s gases are impinged toward it. This system is considered to be the simplest and smallest unit of such power generation devices to have been developed. Methane is used as fuel and an equivalence ratio (φ ) of the mixture (with oxygen) and the distance between the cell and the burner surface (d) are considered as the experimental parameters. It turns out that open circuit voltage increases linearly with the increase of temperature in a wide range of equivalence ratios. However, it increases drastically to the point at which the equivalence ratio becomes small enough (φ   ⩽  2.0 in the present study) within the specific distance range to bring about the appearance of an inner flame. This could provide sufficient heat and oxygen for the anode, contributing to the generation of the cell’s high electric potential. It is also noted that the appearance of the inner flame does not promise to better the performance unless the preferred conditions (high temperature, low oxygen, rich fuel) near the cell are achieved. The Nernst equation works well for predicting the open circuit voltage under the conditions studied. Systematic design of the entire power generation system is preferable when a miniaturized power generation system is considered by applying DFFC.

  5. Combined Power Generation and Carbon Sequestration Using Direct FuelCell

    Hossein Ghezel-Ayagh


    The unique chemistry of carbonate fuel cell offers an innovative approach for separation of carbon dioxide from greenhouse gases (GHG). The carbonate fuel cell system also produces electric power at high efficiency. The simultaneous generation of power and sequestration of greenhouse gases offer an attractive scenario for re-powering the existing coal-fueled power plants, in which the carbonate fuel cell would separate the carbon dioxide from the flue gas and would generate additional pollutant-free electric power. Development of this system is concurrent with emergence of Direct FuelCell{reg_sign} (DFC{reg_sign}) technology for generation of electric power from fossil fuels. DFC is based on carbonate fuel cell featuring internal reforming. This technology has been deployed in MW-scale power plants and is readily available as a manufactured product. This final report describes the results of the conceptualization study conducted to assess the DFC-based system concept for separation of CO2 from GHG. Design and development studies were focused on integration of the DFC systems with coal-based power plants, which emit large amounts of GHG. In parallel to the system design and simulation activities, operation of laboratory scale DFC verified the technical concept and provided input to the design activity. The system was studied to determine its effectiveness in capturing more than ninety percent of CO2 from the flue gases. Cost analysis was performed to estimate the change in cost of electricity for a 200 MW pulverized coal boiler steam cycle plant retrofitted with the DFC-based CO2 separation system producing an additional 127 MW of electric power. The cost increments as percentage of levelized cost of electricity were estimated for a range of separation plant installations per year and a range of natural gas cost. The parametric envelope meeting the goal (<20% increase in COE) was identified. Results of this feasibility study indicated that DFC-based separation

  6. Generating electricity from biofluid with a nanowire-based biofuel cell for self-powered nanodevices

    Pan, Caofeng; Wu, Hui; Ahmad, Mashkoor; Luo, Zhixiang; Xie, Jianbo; Yan, Xinxu; Wu, Lihua; Zhu, Jing [Beijing National Center for Electron Microscopy, Laboratory of Advanced Materials, State Key Laboratory of New Ceramics and Fine Processing, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); The National Center for Nanoscience and Technology (NCNST) of China, Beijing 100080 (China); Fang, Ying; Li, Qiang [The National Center for Nanoscience and Technology (NCNST) of China, Beijing 100080 (China); Wang, Zhong Lin [School Materials Science and Engineering, Georgia Institute of Technology, Atlanta Georgia 30332-0245 (United States)


    We report a nanowire-based biofuel cell based on a single proton conductive polymer nanowire for converting chemical energy from biofluids, such as glucose/blood, into electricity, with glucose oxidase and laccase as catalyst. The glucose is supplied from the biofluid, the nanowire serves as the proton conductor, and the whole cell can be realized at the nano/micrometer scale. The biofuel cell composed of a single nanowire generates an output power as high as 0.5-3 {mu}W, and it has been integrated with a set of nanowire-based sensors for performing self-powered sensing. This study shows the feasibility of building self-powered nanodevices for the biological sciences, environmental monitoring, defense technology, and even personal electronics. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. A Maximum Power Point Tracking Control Method of a Photovoltaic Power Generator with Consideration of Dynamic Characteristics of Solar Cells

    Watanabe, Takashi; Yoshida, Toshiya; Ohniwa, Katsumi

    This paper discusses a new control strategy for photovoltaic power generation systems with consideration of dynamic characteristics of the photovoltaic cells. The controller estimates internal currents of an equivalent circuit for the cells. This estimated, or the virtual current and the actual voltage of the cells are fed to a conventional Maximum-Power-Point-Tracking (MPPT) controller. Consequently, this MPPT controller still tracks the optimum point even though it is so designed that the seeking speed of the operating point is extremely high. This system may suit for applications, which are installed in rapidly changeable insolation and temperature-conditions e.g. automobiles, trains, and airplanes. The proposed method is verified by experiment with a combination of this estimating function and the modified Boehringer's MPPT algorithm.

  8. Design of a mediated enzymatic fuel cell to generate power from renewable fuel sources.

    Korkut, Seyda; Kilic, Muhammet Samet


    The present work reported a compartment-less enzymatic fuel cell (EFC) based on newly synthesized Poly(pyrrole-2-carboxylic acid-co-3-thiophene acetic acid) film containing glucose oxidase and laccase effectively wired by p-benzoquinone incorporated into the copolymer structure. The resulting system generated a power density of 18.8 µW/cm(2) with 30 mM of glucose addition at +0.94 V at room temperature. Improvements to maximize the power output were ensured with step-by-step optimization of electrode fabrication design and operational parameters for operating the system with renewable fuel sources. We demonstrated that the improved fuel cell could easily harvest glucose produced during photosynthesis to produce electrical energy in a simple, renewable and sustainable way by generating a power density of 10 nW/cm(2) in the plant leaf within 2 min. An EFC for the first time was successfully operated in municipal wastewater which contained glycolytic substances to generate electrical energy with a power output of 3.3 µW/cm(2). PMID:26102352

  9. Proton exchange membrane fuel cells for electrical power generation on-board commercial airplanes

    Highlights: ► We examine proton exchange membrane fuel cells on-board commercial airplanes. ► We model the added fuel cell system’s effect on overall airplane performance. ► It is feasible to implement an on-board fuel cell system with current technology. ► Systems that maximize waste heat recovery are the best performing. ► Current PEM and H2 storage technology results in an airplane performance penalty. -- Abstract: Deployed on a commercial airplane, proton exchange membrane (PEM) fuel cells may offer emissions reductions, thermal efficiency gains, and enable locating the power near the point of use. This work seeks to understand whether on-board fuel cell systems are technically feasible, and, if so, if they could offer a performance advantage for the airplane when using today’s off-the-shelf technology. We also examine the effects of the fuel cell system on airplane performance with (1) different electrical loads, (2) different locations on the airplane, and (3) expected advances in fuel cell and hydrogen storage technologies. Through hardware analysis and thermodynamic simulation, we found that an additional fuel cell system on a commercial airplane is technically feasible using current technology. Although applied to a Boeing 787-type airplane, the method presented is applicable to other airframes as well. Recovery and on-board use of the heat and water that is generated by the fuel cell is an important method to increase the benefit of such a system. The best performance is achieved when the fuel cell is coupled to a load that utilizes the full output of the fuel cell for the entire flight. The effects of location are small and location may be better determined by other considerations such as safety and modularity. Although the PEM fuel cell generates power more efficiently than the gas turbine generators currently used, when considering the effect of the fuel cell system on the airplane’s overall performance we found that an overall

  10. Electric power generation by a submersible microbial fuel cell equipped with a membrane electrode assembly.

    Min, Booki; Poulsen, Finn Willy; Thygesen, Anders; Angelidaki, Irini


    Membrane electrode assemblies (MEAs) were incorporated into the cathode chamber of a submersible microbial fuel cell (SMFC). A close contact of the electrodes could produce high power output from SMFC in which anode and cathode electrodes were connected in parallel. In polarization test, the maximum power density was 631 mW/m(2) at current density of 1772 mA/m(2) at 82 Ω. With 180-Ω external resistance, one set of the electrodes on the same side could generate more power density of 832±4 mW/m(2) with current generation of 1923±4 mA/m(2). The anode, inclusive a biofilm behaved ohmic, whereas a Tafel type behavior was observed for the oxygen reduction. The various impedance contributions from electrodes, electrolyte and membrane were analyzed and identified by electrochemical impedance spectroscopy. Air flow rate to the cathode chamber affected microbial voltage generation, and higher power generation was obtained at relatively low air flow less than 2 mL/min. PMID:22705964

  11. Thermoelectric Power Generation in a Vacuum Cell of Decomposing Liquid Potassium-Ammonia Solutions

    Jibeom Kim


    Full Text Available This paper describes the design of high-efficiency reversible thermoelectric conversion devices for thermoelectric power generation through liquid potassium-ammonia (K-NH3 solutions. The validity and effectiveness of the proposed design is verified by thermoelectric experiments using two kinds of “U”-shaped vacuum cells with a NH3-gas passageway connecting both legs of “U”, one of which has a waist in the middle of a liquid flow passage. The experimental results show that the gas passageway provides a stable and reliable reaction by preventing an internal pressure imbalance due to NH3 gasification during solution decomposition; hence, long-term, reversible thermoelectric power can be effectively derived by stably inducing two separate phase transitions in the cell. In addition, the effect of the narrow waist in the cell’s middle is verified to cause an increase in thermoelectric conversion efficiency due to improved electric conductivity of liquid in the vacuum cell. Consequently, using these technologies in thermoelectric cell potentially leads to long-time, high-efficiency thermoelectric power generation through liquid K-NH3 solutions.

  12. Superconducting Power Generation

    Rabinowitz, M


    The superconducting ac generator has the greatest potential for large-scale commercial application of superconductivity that can benefit the public. Electric power is a vital ingredient of modern society, and generation may be considered to be the vital ingredient of a power system. This articles gives background, and an insight into the physics and engineering of superconducting power generation.

  13. Development of planar solid oxide fuel cells for power generation applications

    Minh, N.Q. [AlliedSignal Aerospce Equipment Systems, Torrance, CA (United States)


    Planar solid oxide fuel cells (SOFCs) are presently being developed for a variety of electric power generation application. The planar design offers simple cell geometry, high power density, and multiple fabrication and gas manifolding options. Planar SOFC technology has received much attention recently, and significant progress has been made in this area. Recent effort at AlliedSignal has focused on the development of high-performance, lightweight planar SOFCs, having thin-electrolyte films, that can be operated efficiently at reduced temperatures (< 1000{degrees}C). The advantages of reduced-temperature operation include wider material choice (including use of metallic interconnects), expected longer cell life, reduced thermal stress, improved reliability, and reduced fuel cell cost. The key aspect in the development of thin-film SIFCs is to incorporate the thin electrolyte layer into the desired structure of cells in a manner that yields the required characteristics. AlliedSignal has developed a simple and cost-effective method based on tape calendering for the fabrication of thin-electrolyte SOFCs. Thin-electrolyte cells made by tape calendering have shown extraordinary performance, e.g., producing more than 500mW/cm{sup 2} at 700{degrees}C and 800mW/cm{sup 2} at 800{degrees}C with hydrogen as fuel and air is oxidant. thin-electrolyte single cells have been incorporated into a compliant metallic stack structure and operated at reduced and operated at reduced-temperature conditions.

  14. Fuel-Cell Power Systems Incorporating Mg-Based H2 Generators

    Kindler, Andrew; Narayan, Sri R.


    Two hydrogen generators based on reactions involving magnesium and steam have been proposed as means for generating the fuel (hydrogen gas) for such fuel-cell power systems as those to be used in the drive systems of advanced motor vehicles. The hydrogen generators would make it unnecessary to rely on any of the hydrogen storage systems developed thus far that are, variously, too expensive, too heavy, too bulky, and/or too unsafe to be practical. The two proposed hydrogen generators are denoted basic and advanced, respectively. In the basic hydrogen generator (see figure), steam at a temperature greater than or equals 330 C would be fed into a reactor charged with magnesium, wherein hydrogen would be released in the exothermic reaction Mg + H2O yields MgO + H2. The steam would be made in a flash boiler. To initiate the reaction, the boiler could be heated electrically by energy borrowed from a storage battery that would be recharged during normal operation of the associated fuel-cell subsystem. Once the reaction was underway, heat from the reaction would be fed to the boiler. If the boiler were made an integral part of the hydrogen-generator reactor vessel, then the problem of transfer of heat from the reactor to the boiler would be greatly simplified. A pump would be used to feed water from a storage tank to the boiler.

  15. Magnetohydrodynamic (MHD) power generation

    The concept of MHD power generation, principles of operation of the MHD generator, its design, types, MHD generator cycles, technological problems to be overcome, the current state of the art in USA and USSR are described. Progress of India's experimental 5 Mw water-gas fired open cycle MHD power generator project is reported in brief. (M.G.B.)

  16. MHD Power Generation

    Kantrowitz, Arthur; Rosa, Richard J.


    Explains the operation of the Magnetohydrodynamic (MHD) generator and advantages of the system over coal, oil or nuclear powered generators. Details the development of MHD generators in the United States and Soviet Union. (CP)

  17. Development of reversible solid oxide fuel cell for power generation and hydrogen production

    Jung, G. B.; Chen, J. Y.; Lin, C. Y.; Chan, S. H.


    A reversible solid oxide fuel cell (RSOFC) provides the dual function of performing energy storage and power generation, all in one unit. When functioning as an energy storage device, the RSOFC acts like an electrolyzer in water electrolysis mode; whereby the electric energy is stored as (electrolyzed) hydrogen and oxygen gases. While hydrogen is useful as a transportation fuel and in other industrial applications, the RSOFC also acts as a fuel cell in power generation mode to produce electricity when needed. The RSOFC would be a competitive technology in the upcoming hydrogen economy on the basis of its low cost, simple structure, and high efficiency. This paper reports on the design and manufacturing of its membrane electrode assembly using commercially available materials. Also reported are the resulting performance, both in electrolysis and fuel cell modes, as a function of its operating parameters such as temperature and current density. We found that the RSOFC performance improved with increasing temperature and its fuel cell mode had a better performance than its electrolysis mode due to a limited humidity inlet causing concentration polarization.

  18. Increasing power generation for scaling up single-chamber air cathode microbial fuel cells

    Cheng, Shaoan


    Scaling up microbial fuel cells (MFCs) requires a better understanding the importance of the different factors such as electrode surface area and reactor geometry relative to solution conditions such as conductivity and substrate concentration. It is shown here that the substrate concentration has significant effect on anode but not cathode performance, while the solution conductivity has a significant effect on the cathode but not the anode. The cathode surface area is always important for increasing power. Doubling the cathode size can increase power by 62% with domestic wastewater, but doubling the anode size increases power by 12%. Volumetric power density was shown to be a linear function of cathode specific surface area (ratio of cathode surface area to reactor volume), but the impact of cathode size on power generation depended on the substrate strength (COD) and conductivity. These results demonstrate the cathode specific surface area is the most critical factor for scaling-up MFCs to obtain high power densities. © 2010 Elsevier Ltd.

  19. A simulation study of Solid Oxide fuel cell for IGCC power generation using Aspen Plus

    Rudra, Souman; Kim, Hyung Taek


    The solid oxide fuel cell (SOFC) is a promising technology for electricity generation. Sulfur free syngas from the gas cleaning unit serves as a fuel for SOFC in IGFC (Integrated gasification Fuel cell) power plant. It converts the chemical energy of the fuel gas directly to electric energy and...... more accurate fuel cell model giving an advantage over previous system studies based on simplified SOFC models. The objective of this work is to develop a simulation model of a SOFC for IGFC system, flexible enough for use in future development, capable of predicting system performance under various...... operating conditions and using diverse fuels. The SOFC stack model developed using the chemical process flow sheet simulator Aspen Plus which is of equilibrium type and is based on Gibbs free energy minimization. The SOFC model performs heat and mass balances and considers the ohmic, activation and...

  20. Variation of power generation at different buffer types and conductivities in single chamber microbial fuel cells

    Nam, Joo-Youn


    Microbial fuel cells (MFCs) are operated with solutions containing various chemical species required for the growth of electrochemically active microorganisms including nutrients and vitamins, substrates, and chemical buffers. Many different buffers are used in laboratory media, but the effects of these buffers and their inherent electrolyte conductivities have not been examined relative to current generation in MFCs. We investigated the effect of several common buffers (phosphate, MES, HEPES, and PIPES) on power production in single chambered MFCs compared to a non-buffered control. At the same concentrations the buffers produced different solution conductivities which resulted in different ohmic resistances and power densities. Increasing the solution conductivities to the same values using NaCl produced comparable power densities for all buffers. Very large increases in conductivity resulted in a rapid voltage drop at high current densities. Our results suggest that solution conductivity at a specific pH for each buffer is more important in MFC studies than the buffer itself given relatively constant pH conditions. Based on our analysis of internal resistance and a set neutral pH, phosphate and PIPES are the most useful buffers of those examined here because pH was maintained close to the pKa of the buffer, maximizing the ability of the buffer to contribute to increase current generation at high power densities. © 2009 Elsevier B.V. All rights reserved.

  1. Thermoelectric Power Generation in a Vacuum Cell of Decomposing Liquid Potassium-Ammonia Solutions

    Jibeom Kim; Kyuchol Shim; Joonhyeon Jeon


    This paper describes the design of high-efficiency reversible thermoelectric conversion devices for thermoelectric power generation through liquid potassium-ammonia (K-NH 3 ) solutions. The validity and effectiveness of the proposed design is verified by thermoelectric experiments using two kinds of “U†-shaped vacuum cells with a NH 3 -gas passageway connecting both legs of “U†, one of which has a waist in the middle of a liquid flow passage. The experimental results show that the gas...

  2. Power generation enhancement in novel microbial carbon capture cells with immobilized Chlorella vulgaris

    Zhou, Minghua; He, Huanhuan; Jin, Tao; Wang, Hongyu


    With the increasing concerns for global climate change, a sustainable, efficient and renewable energy production from wastewater is imperative. In this study, a novel microbial carbon capture cell (MCC), is constructed for the first time by the introduction of immobilized microalgae (Chlorella vulgaris) into the cathode chamber of microbial fuel cells (MFCs) to fulfill the zero discharge of carbon dioxide. This process can achieve an 84.8% COD removal, and simultaneously the maximum power density can reach 2485.35 mW m-3 at a current density of 7.9 A m-3 and the Coulombic efficiency is 9.40%, which are 88% and 57.7% greater than that with suspended C. vulgaris, respectively. These enhancements in performance demonstrate the feasibility of an economical and effective approach for the simultaneous wastewater treatment, electricity generation and biodiesel production from microalgae.

  3. Design and implementation of a hybrid power generation system with fuel cells and batteries

    Hua, C.C.; Syu, W.C. [National Yunlin Univ. of Science and Technology, Douliou, Yunlin, Taiwan (China). Dept. of Electrical Engineering


    A hybrid power generation system with fuel cells and batteries was presented with particular reference to its soft-switching method and control scheme for an isolated step-up full bridge converter. The design considered leakage inductance of the transformer to assist energy conversion. This can improve the low efficiency and control problems resulting from leakage inductance. A set of clamping-diodes was used to mitigate the ringing of the transformer and output filter diodes. The converter can operate in low temperature and low voltage stress caused by the low efficiency and ringing. A soft-commutating criterion was also discussed. Zero-voltage-switching was achieved for the switches of the full-bridge converter that can efficiently reduce the switching losses. The system can operate in a continuous 740 W. Peak 1 kW was built using a proton exchange membrane fuel cell (PEMFC) having a voltage range of about 22 to 42 V and two 26 Ah lead-acid batteries in series with nominal voltage 24 V, respectively. The bi-directional converter with flexible control strategy can provide power sharing and energy storage at different load conditions, rendering it suitable for PEMFC powered AC applications. Tested results were presented to verify the performance of the system. 11 refs., 15 figs.

  4. Microbial carbon capture cell using cyanobacteria for simultaneous power generation, carbon dioxide sequestration and wastewater treatment.

    Pandit, Soumya; Nayak, Bikram Kumar; Das, Debabrata


    Microbial carbon capture cells (MCCs) were constructed with cyanobacteria growing in a photo biocathode in dual-chambered flat plate mediator-less MFCs separated by an anion exchange membrane from the anode compartment containing Shewanella putrefaciens. The performance of the MCC with Anabaena sparged with CO(2)-air mixture was compared with that of a conventional cathode sparged with air only. The power densities achieved were 57.8 mW/m(2) for Anabaena sparged with a CO(2)-air mixture, 39.2 mW/m(2) for CO(2)-air mixture sparging only, 29.7 mW/m(2) for Anabaena sparged with air, and 19.6 mW/m(2) for air sparging only. The pH of the cathode containing Anabaena gradually increased from 7 to 9.12 and power generation decreased from 34.7 to 23.8 mW/m(2) 17 due to pH imbalance associated voltage losses without CO(2)-air mixture sparging. Sparging with a 5% CO(2)-air mixture produced maximum power of 100.1 mW/m(2). In addition, the power density of MCC increased by 31% when nitrate was added into the catholyte. PMID:22221988

  5. Power generation technologies

    Breeze, Paul


    The new edition of Power Generation Technologies is a concise and readable guide that provides an introduction to the full spectrum of currently available power generation options, from traditional fossil fuels and the better established alternatives such as wind and solar power, to emerging renewables such as biomass and geothermal energy. Technology solutions such as combined heat and power and distributed generation are also explored. However, this book is more than just an account of the technologies - for each method the author explores the economic and environmental costs and risk factor

  6. Effect of C/N ratio and salinity on power generation in compost microbial fuel cells.

    Md Khudzari, Jauharah; Tartakovsky, Boris; Raghavan, G S Vijaya


    In this work, compost Microbial Fuel Cells (cMFCs) were used to generate electricity from a mix of fruit and vegetable wastes, and soil with different C/N ratios and salinities. Experiments were carried out in 500mL cMFCs equipped with carbon felt anodes and manganese dioxide cathodes. The cMFCs were loaded with fresh compost and operated at 20-23°C for up to 97days. The low C/N ratio (C/N 24) had a greater power production with a maximum power density of 5.29mW/m(2) (71.43mW/m(3)), indicating a more favorable condition for microbial growth. High-saline cMFCs produced lower power, suggesting that their level of salinity (10g/L of NaCl) inhibited electricigenic microorganisms. The closed-circuit cMFC showed an improved degradation of organic matter by 6% to 8% compared to the control MFC operated in an open circuit mode (no external resistor attached). PMID:26611399

  7. Power generation statistics

    The frost in February increased the power demand in Finland significantly. The total power consumption in Finland during January-February 2001 was about 4% higher than a year before. In January 2001 the average temperature in Finland was only about - 4 deg C, which is nearly 2 degrees higher than in 2000 and about 6 degrees higher than long term average. Power demand in January was slightly less than 7.9 TWh, being about 0.5% less than in 2000. The power consumption in Finland during the past 12 months exceeded 79.3 TWh, which is less than 2% higher than during the previous 12 months. In February 2001 the average temperature was - 10 deg C, which was about 5 degrees lower than in February 2000. Because of this the power consumption in February 2001 increased by 5%. Power consumption in February was 7.5 TWh. The maximum hourly output of power plants in Finland was 13310 MW. Power consumption of Finnish households in February 2001 was about 10% higher than in February 2000, and in industry the increase was nearly zero. The utilization rate in forest industry in February 2001 decreased from the value of February 2000 by 5%, being only about 89%. The power consumption of the past 12 months (Feb. 2000 - Feb. 2001) was 79.6 TWh. Generation of hydroelectric power in Finland during January - February 2001 was 10% higher than a year before. The generation of hydroelectric power in Jan. - Feb. 2001 was nearly 2.7 TWh, corresponding to 17% of the power demand in Finland. The output of hydroelectric power in Finland during the past 12 months was 14.7 TWh. The increase from the previous 12 months was 17% corresponding to over 18% of the power demand in Finland. Wind power generation in Jan. - Feb. 2001 was exceeded slightly 10 GWh, while in 2000 the corresponding output was 20 GWh. The degree of utilization of Finnish nuclear power plants in Jan. - Feb. 2001 was high. The output of these plants was 3.8 TWh, being about 1% less than in Jan. - Feb. 2000. The main cause for the

  8. Design and Experimental Validation of a Robust Control Method for a Hybrid Fuel Cell Power Generation System

    Hernandez-Torres, David; Riu, Delphine; Sename, Olivier


    In this article a robust control methodology is proposed for an hybrid power generation structure composed by a Fuel Cell and a Super-capacitor. The control strategy and the desired performances are written as inequality constraints so they can be solved using Linear Matrix Inequalities methods. Using this method a multivariable PI control with H∞ performance is computed, which is used to control the power converters associated with the Fuel Cell and the Super-capacitor respectively. The cont...

  9. Electric power generation

    Apart from discussing some principles of power industry the present text deals with the different ways of electric power generation. Both the conventional methods of energy conversion in heating and water power stations and the facilities for utilizing regenerative energy sources (sun, wind, ground heat, tidal power) are considered. The script represents the essentials of the lecture of the same name which is offered to the students of the special subject 'electric power engineering' at the Fachhochschule Hamburg. It does not require any special preliminary knowledge except for the general principles of electrical engineering. It is addressing students of electrical engineering who have passed their preliminary examination at technical colleges and universities. Moreover, it shall also be of use for engineers who want to obtain a quick survey of the structure and the operating characteristics of the extremely different technical methods of power generation. (orig.)

  10. Engine-integrated solid oxide fuel cells for efficient electrical power generation on aircraft

    Waters, Daniel F.; Cadou, Christopher P.


    This work investigates the use of engine-integrated catalytic partial oxidation (CPOx) reactors and solid oxide fuel cells (SOFCs) to reduce fuel burn in vehicles with large electrical loads like sensor-laden unmanned air vehicles. Thermodynamic models of SOFCs, CPOx reactors, and three gas turbine (GT) engine types (turbojet, combined exhaust turbofan, separate exhaust turbofan) are developed and checked against relevant data and source material. Fuel efficiency is increased by 4% and 8% in the 50 kW and 90 kW separate exhaust turbofan systems respectively at only modest cost in specific power (8% and 13% reductions respectively). Similar results are achieved in other engine types. An additional benefit of hybridization is the ability to provide more electric power (factors of 3 or more in some cases) than generator-based systems before encountering turbine inlet temperature limits. A sensitivity analysis shows that the most important parameters affecting the system's performance are operating voltage, percent fuel oxidation, and SOFC assembly air flows. Taken together, this study shows that it is possible to create a GT-SOFC hybrid where the GT mitigates balance of plant losses and the SOFC raises overall system efficiency. The result is a synergistic system with better overall performance than stand-alone components.

  11. Bioelectricity generation and microcystins removal in a blue-green algae powered microbial fuel cell

    Bioelectricity production from blue-green algae was examined in a single chamber tubular microbial fuel cell (MFC). The blue-green algae powered MFC produced a maximum power density of 114 mW/m2 at a current density of 0.55 mA/m2. Coupled with the bioenergy generation, high removal efficiencies of chemical oxygen demand (COD) and nitrogen were also achieved in MFCs. Over 78.9% of total chemical oxygen demand (TCOD), 80.0% of soluble chemical oxygen demand (SCOD), 91.0% of total nitrogen (total-N) and 96.8% ammonium-nitrogen (NH3-N) were removed under closed circuit conditions in 12 days, which were much more effective than those under open circuit and anaerobic reactor conditions. Most importantly, the MFC showed great ability to remove microcystins released from blue-green algae. Over 90.7% of MC-RR and 91.1% of MC-LR were removed under closed circuit conditions (500 Ω). This study showed that the MFC could provide a potential means for electricity production from blue-green algae coupling algae toxins removal.

  12. Power generation by packed-bed air-cathode microbial fuel cells

    Zhang, Xiaoyuan


    Catalysts and catalyst binders are significant portions of the cost of microbial fuel cell (MFC) cathodes. Many materials have been tested as aqueous cathodes, but air-cathodes are needed to avoid energy demands for water aeration. Packed-bed air-cathodes were constructed without expensive binders or diffusion layers using four inexpensive carbon-based materials. Cathodes made from activated carbon produced the largest maximum power density of 676±93mW/m2, followed by semi-coke (376±47mW/m2), graphite (122±14mW/m2) and carbon felt (60±43mW/m2). Increasing the mass of activated carbon and semi-coke from 5 to ≥15g significantly reduced power generation because of a reduction in oxygen transfer due to a thicker water layer in the cathode (~3 or ~6cm). These results indicate that a thin packed layer of activated carbon or semi-coke can be used to make inexpensive air-cathodes for MFCs. © 2013 Elsevier Ltd.

  13. Power generation from organic substrate in batch and continuous flow microbial fuel cell operations

    Highlights: → Power generation was investigated in a single MFC at batch and continuous modes. → Continuous MFCs offer some advantages over batch systems for practical applications. → Polarity and cyclic voltammetry, were adopted to analyze experimental data. → OCV was stable for the duration of 72 h of operation time in batch system. → At optimum HRT (6.7 h), maximum output were 1210 mA m-2 and 283 mW m-2, respectively. -- Abstract: Microbial fuel cells (MFCs) are biochemical-catalyzed systems in which electricity is produced by oxidizing biodegradable organic matters in presence of either bacteria or enzyme. This system can serve as a device for generating clean energy and, also wastewater treatment unit. In this paper, production of bioelectricity in MFC in batch and continuous systems were investigated. A dual chambered air-cathode MFC was fabricated for this purpose. Graphite plates were used as electrodes and glucose as a substrate with initial concentration of 30 g l-1 was used. Cubic MFC reactor was fabricated and inoculated with Saccharomyces cerevisiae PTCC 5269 as active biocatalyst. Neutral red with concentration of 200 μmol l-1 was selected as electron shuttle in anaerobic anode chamber. In order to enhance the performance of MFC, potassium permanganate at 400 μmol l-1 concentration as oxidizer was used. The performance of MFC was analyzed by the measurement of polarization curve and cyclic volatmmetric data as well. Closed circuit voltage was obtained using a 1 kΩ resistance. The voltage at steady-state condition was 440 mV and it was stable for the entire operation time. In a continuous system, the effect of hydraulic retention time (HRT) on performance of MFC was examined. The optimum HRT was found to be around 7 h. Maximum produced power and current density at optimum HRT were 1210 mA m-2 and 283 mW m-2, respectively.

  14. Gearless wind power generator

    Soederlund, L.; Ridanpaeae, P.; Vihriaelae, H.; Peraelae, R. [Tampere Univ. of Technology (Finland). Lab. of Electricity and Magnetism


    During the wind power generator project a design algorithm for a gearless permanent magnet generator with an axially orientated magnetic flux was developed and a 10 kW model machine was constructed. Utilising the test results a variable wind speed system of 100 kW was designed that incorporates a permanent magnet generator, a frequency converter and a fuzzy controller. This system produces about 5-15% more energy than existing types and stresses to the blades are minimised. The type of generator designed in the project represents in general a gearless solution for slow-speed electrical drives. (orig.)

  15. Electric power generating bicycle

    Brito, Nuno; Ribeiro, Luís; Esteves, João Sena


    It is manifest the growing interest in both personal health and environmental issues. The device described on this paper contemplates both aspects: generating environment-friendly electric power while keeping fit. A car alternator excited through a 12V battery is coupled to a mountain bicycle, and this arrangement enables the lighting of six halogen lamps, if a cyclist pedals fast enough. Such a machine gives rise to the thought of a self-powered gymnasium. Considerable physical effort is req...

  16. Wind electric power generation

    The monthly statistics of wind electric power generation in Denmark are compiled from information given by the owners of private wind turbines. For each wind turbine the name of the site and of the type of turbine is given, and the power generation data are given for the month in question together with the total production in 1988 and 1989. Also the data of operation start are given. On the map of Denmark the sites of the wind turbines are marked. The statistics for December 1994 comprise 2328 wind turbines

  17. Electrogasdynamic Power Generation

    EGD power generation is one of many so-called direct energy conversion methods being considered for application to large-scale power generation. A typical cycle would consist of the following: Air and fuel are burned at relatively high pressure (120-450 lb/in2) in a combustion chamber. The combustion gas is then introduced into tubes made of a dielectric material (ceramic with high resistivity). At the entrance of these tubes, the gas is partially ionized by a corona discharge. The tubes are provided with an attractor electrode near the entrance and a collector electrode near the exit. An electric field in the tube is established by virtue of the external resistance in the connection between attractor and collector electrodes. This field offers resistance to the flow of gas seeded with ions. In the process of overcoming this resistance, kinetic energy of the gas stream is used. As the ions are pushed downstream they are collected on the collector electrode where they build up a high charge. In many ways this EGD process is like a Van de Graaff generator with the gas stream taking the place of the mechanically driven belt used in Van de Graaff machines. The great advantage of EGD power generation over MHD is the fact that high electrical conductivity of the gas stream is not necessary for EGD. For this reason the EGD process can be carried out at temperatures which are well within the limits of today’s technology. This same reason provides a second advantage; it is not necessary to limit the total amount of power generated in the direct conversion section. In MHD schemes, the conductivity of the gas is so low at temperatures below 3600°F (∼1980°C) that subsequent extraction of power from the gas stream has to be accomplished by conventional steam generation. This has the effect of degrading the overall efficiency of the cycle. In EGD systems, work can be extracted directly from the gas stream down to near atmospheric temperatures. High thermal efficiencies are

  18. Magnetohydrodynamic power generation

    The paper describes research and development in the field of magnetohydrodynamic power generation technology, based on discussions held in the Joint IAEA/UNESCO International Liaison Group on MHD electrical power generation. Research and development programmes on open cycle, closed cycle plasma and liquid-metal MHD are described. Open cycle MHD has now entered the engineering development stage. The paper reviews the results of cycle analyses and economic and environmental evaluations: substantial agreement has been reached on the expected overall performance and necessary component specifications. The achievement in the Soviet Union on the U-25 MHD pilot plant in obtaining full rated electrical power of 20.4 MW is described, as well as long duration testing of the integrated operation of MHD components. Work in the United States on coal-fired MHD generators has shown that, with slagging of the walls, a run time of about one hundred hours at the current density and electric field of a commercial MHD generator has been achieved. Progress obtained in closed cycle plasma and liquid metal MHD is reviewed. Electrical power densities of up to 140 MWe/m3 and an enthalpy extraction as high as 24 per cent have been achieved in noble gas MHD generator experiments. (Auth.)

  19. Energy production from marine biomass: Fuel cell power generation driven by methane produced from seaweed

    Yokoyama, S.; Imou, K. [Univ. of Tokyo (Japan). Dept. of Biological and Environmental Engineering; Jonouchi, K. [Yanmar Co. Ltd., Osaka (Japan). Dept. of Human Resources


    Global warming has become one of the most serious environmental problems. To cope with the problem, it is necessary to substitute renewable energy for nonrenewable fossil fuel. Biomass, which is one of the renewable energies, is considered to be carbon-neutral, meaning that the net CO{sub 2} concentration in the atmosphere remains unchanged provided the CO{sub 2} emitted by biomass combustion and that fixed by photosynthesis are balanced. Biomass is also unique because it is the only organic matter among renewable energies. In other words, fuels and chemicals can be produced from biomass in addition to electricity and heat. Marine biomass has attracted less attention than terrestrial biomass for energy utilization so far, but is work considering especially for a country like Japan which has long available coastlines. This paper discusses the utilization of marine biomass as an energy resource in Japan. A marine biomass energy system in Japan was proposed consisting of seaweed cultivation (Laminaria japonica) at offshore marine farms, biogas production via methane fermentation of the seaweeds, and fuel cell power generation driven by the generated biogas. The authors estimated energy output, energy supply potential, and CO{sub 2} mitigation in Japan on the basis of the proposed system. As a result, annual energy production was estimated to be 1.02 x 10{sup 9} kWh/yr at nine available sites. Total CO{sub 2} mitigation was estimated to be 1.04 x 10{sup 6} tonnes per annum at the nine sites. However, the CO{sub 2} emission for the construction of relevant facilities is not taken into account in this paper. The estimated CO{sub 2} mitigation is equivalent to about 0.9% of the required CO{sub 2} mitigation for Japan per annum under the Kyoto Protocol framework.

  20. Nuclear power generation device

    In a PWR type reactor, a free piston type stirling engine is disposed instead of a conventional steam generator and a turbine. Since the stirling engine does not cause radiation leakage in view of the structure, safety and reliability of the nuclear power generation are improved. Further, the thermal cycle, if it operates theoretically, is equivalent with a Carnot cycle having the highest thermodynamical heat efficiency, thereby enabling to obtain a high heat efficiency in an actual engine. (N.H.)

  1. The changing nature of the power generation market — does it create opportunities for fuel cells?

    Cragg, C. T.

    This paper surveys the global power industry seeking trends that might encourage greater use of full cells. The subject is broken into four basic themes: (i) an increasing demand for electricity, and this may not be solved by the traditional form of the integrated state-owned, centralised power utility, with a large infrastructure grid attached, the load curves of these integrated grids becoming unmanageable; (ii) a general trend towards privatisation and deregulation in the power sector, that is shifting its control from an engineering to a commercial paradigm, with unforseen consequences; (iii) contrary to (ii), the need for supplying security in its most basic sense is increasing rather than declining as power-dependent technology becomes progressively more important in the modern economy, and (iv) the trend in technology, particularly environmental-friendly technology, is towards smaller size of production centres. Within these inter-related themes these are encouraging prospects for the fuel cell community.

  2. Anode modification with formic acid: A simple and effective method to improve the power generation of microbial fuel cells

    Liu, Weifeng; Cheng, Shaoan, E-mail:; Guo, Jian


    Highlights: • Carbon cloth anode is modified with formic acid by a simple and reliable approach. • The modification significantly enhances the power output of microbial fuel cells. • The modified anode surface favors the bacterial attachment and growth on anode. • The electron transfer rate of anode is promoted. - Abstract: The physicochemical properties of anode material directly affect the anodic biofilm formation and electron transfer, thus are critical for the power generation of microbial fuel cells (MFCs). In this work, carbon cloth anode was modified with formic acid to enhance the power production of MFCs. Formic acid modification of anode increased the maximum power density of a single-chamber air-cathode MFC by 38.1% (from 611.5 ± 6 mW/m{sup 2} to 877.9 ± 5 mW/m{sup 2}). The modification generated a cleaner electrode surface and a reduced content of oxygen and nitrogen groups on the anode. The surface changes facilitated bacterial growth on the anode and resulted in an optimized microbial community. Thus, the electron transfer rate on the modified anodes was enhanced remarkably, contributing to a higher power output of MFCs. Anode modification with formic acid could be an effective and simple method for improving the power generation of MFCs. The modification method holds a huge potential for large scale applications and is valuable for the scale-up and commercialization of microbial fuel cells.

  3. MHD power generation system

    The present invention provides a power generation system of high energy efficiency comprising, in combination, a FBR type reactor using liquid metal as coolants and a liquid MHD power generator. That is, a preheater is disposed to the downstream of a condenser in a turbine power generation system and a heat exchanger is disposed to the upstream of a mixer in a gas system. Then, a high temperature gas from a separator is introduced into the preheater and sufficiently lowered for the temperature and then pressurized in a pump. Then, the pressurized gas is passed through the heat exchanger and heated. Thus, heat energy possessed in the high temperature gas from the separator is used for preheating the hydraulic fluid of the turbine power generation system through the preheater. Accordingly, the heat energy can effectively be utilized instead of being discharged out of the system as usual. Further, when the gas deprived of heat energy and cooled to a lower temperature is pressurized by the pump and heated by the heat exchanger, the heat energy is received from liquid metals of FBR type reactor and, accordingly, the energy efficiency can be improved as compared with the conventional re-heating system. (I.S.)

  4. Energy Supply Characteristics of a Combined Solar Cell and Diesel Engine System with a Prediction Algorithm for Solar Power Generation

    El-Sayed, Abeer Galal; Obara, Shin'ya

    The production of electricity from the solar cells continues to attract interest as a power source for distributed energy generation. It is important to be able to estimate solar cell power to optimize system energy management. This paper proposes a prediction algorithm based on a neural network (NN) to predict the electricity production from a solar cell. The operation plan for a combined solar cell and diesel engine generator system is examined using the NN prediction algorithm. Two systems are examined in this paper: one with and one without a power storage facility. Comparisons are presented of the results from the two systems with respect to the actual calculations of output power and the predicted electricity production from the solar cell. The exhaust heat from the engine is used to supply the heat demand. A back-up boiler is operated when the engine exhaust heat is insufficient to meet the heat demand. Electricity and heat are supplied to the demand side from the proposed systems, and no external sources are used. When the NN production-of-electricity prediction was introduced, the engine generator operating time was reduced by 12.5% in December and 16.7% for March and September. Moreover, an operation plan for the combined system exhaust heat is proposed, and the heat output characteristics of the back-up boiler are characterized.

  5. Proton exchange membrane fuel cells for electrical power generation on-board commercial airplanes.

    Curgus, Dita Brigitte; Munoz-Ramos, Karina (Sandia National Laboratories, Albuquerque, NM); Pratt, Joseph William; Akhil, Abbas Ali (Sandia National Laboratories, Albuquerque, NM); Klebanoff, Leonard E.; Schenkman, Benjamin L. (Sandia National Laboratories, Albuquerque, NM)


    Deployed on a commercial airplane, proton exchange membrane fuel cells may offer emissions reductions, thermal efficiency gains, and enable locating the power near the point of use. This work seeks to understand whether on-board fuel cell systems are technically feasible, and, if so, if they offer a performance advantage for the airplane as a whole. Through hardware analysis and thermodynamic and electrical simulation, we found that while adding a fuel cell system using today's technology for the PEM fuel cell and hydrogen storage is technically feasible, it will not likely give the airplane a performance benefit. However, when we re-did the analysis using DOE-target technology for the PEM fuel cell and hydrogen storage, we found that the fuel cell system would provide a performance benefit to the airplane (i.e., it can save the airplane some fuel), depending on the way it is configured.

  6. Proton Exchange Membrane Fuel Cells for Electrical Power Generation On-Board Commercial Airplanes

    Pratt, Joesph W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Klebanoff, Leonard E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Munoz-Ramos, Karina [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Akhil, Abbas A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Curgus, Dita B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Schenkman, Benjamin L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    Deployed on a commercial airplane, proton exchange membrane fuel cells may offer emissions reductions, thermal efficiency gains, and enable locating the power near the point of use. This work seeks to understand whether on-board fuel cell systems are technically feasible, and, if so, if they offer a performance advantage for the airplane as a whole. Through hardware analysis and thermodynamic and electrical simulation, we found that while adding a fuel cell system using today’s technology for the PEM fuel cell and hydrogen storage is technically feasible, it will not likely give the airplane a performance benefit. However, when we re-did the analysis using DOE-target technology for the PEM fuel cell and hydrogen storage, we found that the fuel cell system would provide a performance benefit to the airplane (i.e., it can save the airplane some fuel), depending on the way it is configured.

  7. Electric power generation by a submersible microbial fuel cell equipped with a membrane electrode assembly

    Min, Booki; Poulsen, Finn Willy; Thygesen, Anders;


    Membrane electrode assemblies (MEAs) were incorporated into the cathode chamber of a submersible microbial fuel cell (SMFC). A close contact of the electrodes could produce high power output from SMFC in which anode and cathode electrodes were connected in parallel. In polarization test, the...

  8. Treatment of carbon fiber brush anodes for improving power generation in air–cathode microbial fuel cells

    Feng, Yujie


    Carbon brush electrodes have been used to provide high surface areas for bacterial growth and high power densities in microbial fuel cells (MFCs). A high-temperature ammonia gas treatment has been used to enhance power generation, but less energy-intensive methods are needed for treating these electrodes in practice. Three different treatment methods are examined here for enhancing power generation of carbon fiber brushes: acid soaking (CF-A), heating (CF-H), and a combination of both processes (CF-AH). The combined heat and acid treatment improve power production to 1370 mW m-2, which is 34% larger than the untreated control (CF-C, 1020 mW m-2). This power density is 25% higher than using only acid treatment (1100 mW m-2) and 7% higher than that using only heat treatment (1280 mW m-2). XPS analysis of the treated and untreated anode materials indicates that power increases are related to higher N1s/C1s ratios and a lower C-O composition. These findings demonstrate efficient and simple methods for improving power generation using graphite fiber brushes, and provide insight into reasons for improving performance that may help to further increase power through other graphite fiber modifications. © 2009 Elsevier B.V. All rights reserved.

  9. Future nuclear power generation

    The book includes an introduction then it speaks about the options to secure sources of energy, nuclear power option, nuclear plants to generate energy including light-water reactors (LWR), heavy-water reactors (HWR), advanced gas-cooled reactors (AGR), fast breeder reactors (FBR), development in the manufacture of reactors, fuel, uranium in the world, current status of nuclear power generation, economics of nuclear power, nuclear power and the environment and nuclear power in the Arab world. A conclusion at the end of the book suggests the increasing demand for energy in the industrialized countries and in a number of countries that enjoy special and economic growth such as China and India pushes the world to search for different energy sources to insure the urgent need for current and anticipated demand in the near and long-term future in light of pessimistic and optimistic outlook for energy in the future. This means that states do a scientific and objective analysis of the currently available data for the springboard to future plans to secure the energy required to support economy and welfare insurance.

  10. Assessment of the implementation issues for fuel cells in domestic and small scale stationary power generation and CHP applications

    Graham, G.; Cruden, A.; Hart, J.


    This report discusses implementation issues associated with the use of fuel cells in <10 kW domestic, small-scale power generation and combined heat and power (CHP) operations in the UK. The report examines the key issues (fuel cell system standards and certification, fuel infrastructure, commercial issues and competing CHP technologies), before discussing non-technical issues including finance, ownership, import and export configuration, pricing structure, customer acceptability, installation, operation and training of servicing and commissioning personnel. The report goes on to discuss market and technical drivers, grid connection issues and solutions, operations and maintenance. Recommendations for the future are made.

  11. Increased power generation from primary sludge by a submersible microbial fuel cell and optimum operational conditions

    Vologni, Valentina; Kakarla, Ramesh; Angelidaki, Irini;


    Microbial fuel cells (MFCs) have received attention as a promising renewable energy technology for waste treatment and energy recovery. We tested a submersible MFC with an innovative design capable of generating a stable voltage of 0.250 ± 0.008 V (with a fixed 470 Ω resistor) directly from primary...

  12. Analysis and control of an in situ hydrogen generation and fuel cell power system for automotive applications

    Kolavennu, Panini K.

    A new future in automotive transportation is approaching where vehicles are powered by new, clean and efficient energy sources. While different technologies will contribute to this future, many see fuel cells as the leading long term candidate for becoming the power source for emissions-free, mass produced light vehicles. The development of emissions-free vehicles, which run directly on hydrogen, is the true long term goal. However significant difficulties exist in developing these vehicles, due to hydrogen storage problems. For automotive applications, it is desirable to use a carbon-based hydrogenous fuel. The focus of this research was to analyze a fuel cell system for automotive applications, which generated hydrogen in situ using methane as a fuel source. This system consists of four parts: (1) an in situ hydrogen generation subsystem, (2) a power generation subsystem, (3) a thermal management subsystem and (4) a switching control subsystem. The novelty of this research lies in the fact that the entire system was considered from a systems engineering viewpoint with realistic constraints. A fuel processor subsystem was designed and its volume optimized to less than 100 liters. A relationship between the fuel fed into the fuel processor and the hydrogen coming out of it was developed. Using a fuel cell model an overall relationship between the fuel feed rate and the power output was established. The fuel cell car must be fully operational within a minute or so of a cold-start and must respond to rapidly varying loads. Significant load transitions occur frequently as a result of changes in driving conditions. These engineering constraints were addressed by coupling a battery to the fuel cell. A switching controller was designed and it was validated using realistic power profiles. Finally, a model reference adaptive controller was designed to handle nonlinearities and load transitions. The adaptive controller performance was enhanced by adding dead zone

  13. Power Generation Enhancement by Utilizing Plant Photosynthate in Microbial Fuel Cell Coupled Constructed Wetland System

    Shentan Liu; Hailiang Song; Xianning Li; Fei Yang


    In the present study, a new technology that coupled constructed wetland (CW) with microbial fuel cell (MFC) (CW-MFC) was developed to convert solar energy into electricity on the principles of photosynthetic MFC by utilizing root exudates of Ipomoea aquatica as part of fuel. The maximum power density of 12.42 mW m−2 produced from the CW-MFC planted with Ipomoea aquatica was 142% higher than that of 5.13 mW m−2 obtained from the unplanted CW-MFC. The maximum power output for the planted CW-MFC...

  14. Pretreated Landfill Gas Conversion Process via a Catalytic Membrane Reactor for Renewable Combined Fuel Cell-Power Generation

    Zoe Ziaka


    Full Text Available A new landfill gas-based reforming catalytic processing system for the conversion of gaseous hydrocarbons, such as incoming methane to hydrogen and carbon oxide mixtures, is described and analyzed. The exit synthesis gas (syn-gas is fed to power effectively high-temperature fuel cells such as SOFC types for combined efficient electricity generation. The current research work is also referred on the description and design aspects of permreactors (permeable reformers carrying the same type of landfill gas-reforming reactions. Membrane reactors is a new technology that can be applied efficiently in such systems. Membrane reactors seem to perform better than the nonmembrane traditional reactors. The aim of this research includes turnkey system and process development for the landfill-based power generation and fuel cell industries. Also, a discussion of the efficient utilization of landfill and waste type resources for combined green-type/renewable power generation with increased processing capacity and efficiency via fuel cell systems is taking place. Moreover, pollution reduction is an additional design consideration in the current catalytic processors fuel cell cycles.

  15. Power generation using an activated carbon fiber felt cathode in an upflow microbial fuel cell

    Deng, Qian


    An activated carbon fiber felt (ACFF) cathode lacking metal catalysts is used in an upflow microbial fuel cell (UMFC). The maximum power density with the ACFF cathode is 315 mW m-2, compared to lower values with cathodes made of plain carbon paper (67 mW m-2), carbon felt (77 mW m-2), or platinum-coated carbon paper (124 mW m-2, 0.2 mg-Pt cm-2). The addition of platinum to the ACFF cathode (0.2 mg-Pt cm-2) increases the maximum power density to 391 mW m-2. Power production is further increased to 784 mW m-2 by increasing the cathode surface area and shaping it into a tubular form. With ACFF cutting into granules, the maximum power is 481 mW m-2 (0.5 cm granules), and 667 mW m-2 (1.0 cm granules). These results show that ACFF cathodes lacking metal catalysts can be used to substantially increase power production in UMFC compared to traditional materials lacking a precious metal catalyst. © 2009 Elsevier B.V.

  16. Power Generation Enhancement by Utilizing Plant Photosynthate in Microbial Fuel Cell Coupled Constructed Wetland System

    Shentan Liu


    Full Text Available In the present study, a new technology that coupled constructed wetland (CW with microbial fuel cell (MFC (CW-MFC was developed to convert solar energy into electricity on the principles of photosynthetic MFC by utilizing root exudates of Ipomoea aquatica as part of fuel. The maximum power density of 12.42 mW m−2 produced from the CW-MFC planted with Ipomoea aquatica was 142% higher than that of 5.13 mW m−2 obtained from the unplanted CW-MFC. The maximum power output for the planted CW-MFC could be divided into two parts: the maximum power yield from in the water body was 66.05 KJ Kg−1  , and the maximum power transformation from plant photosynthesis was 2.31 GJ ha−1 year−1. The average COD removal efficiencies were 92.1% and 94.8% in the unplanted CW-MFC and planted CW-MFC, respectively; the average TN removal efficiencies amounted to 54.4% and 90.8% in the unplanted CW-MFC and planted CW-MFC. This research demonstrates that planting Ipomoea aquatica in the CW-MFC achieved a higher power density and nutrient removal of nitrogen simultaneously.


    Boyd, Tonya


    Oregon Institute of Technology (OIT) drilled a deep geothermal well on campus (to 5,300 feet deep) which produced 196oF resource as part of the 2008 OIT Congressionally Directed Project. OIT will construct a geothermal power plant (estimated at 1.75 MWe gross output). The plant would provide 50 to 75 percent of the electricity demand on campus. Technical support for construction and operations will be provided by OIT’s Geo-Heat Center. The power plant will be housed adjacent to the existing heat exchange building on the south east corner of campus near the existing geothermal production wells used for heating campus. Cooling water will be supplied from the nearby cold water wells to a cooling tower or air cooling may be used, depending upon the type of plant selected. Using the flow obtained from the deep well, not only can energy be generated from the power plant, but the “waste” water will also be used to supplement space heating on campus. A pipeline will be construction from the well to the heat exchanger building, and then a discharge line will be construction around the east and north side of campus for anticipated use of the “waste” water by facilities in an adjacent sustainable energy park. An injection well will need to be drilled to handle the flow, as the campus existing injection wells are limited in capacity.

  18. Super power generators

    PROTO II, a super power generator, is presently undergoing testing at Sandia Laboratories. It has operated with an 80 ns, 50 ns, 35 ns, and 20 ns positive output pulse high voltage mode and achieved total current rates of rise of 4 x 1014 A/s. The two sided disk accelerator concept using two diodes has achieved voltages of 1.5 MV and currents of 4.5 MA providing a power exceeding 6 TW in the electron beam and 8 TW in the transmission lines. A new test bed named MITE (Magnetically Insulated Transmission Experiment) was designed and is now being tested. The pulse forming lines are back to back short pulse Blumleins which use untriggered water switching. Output data showing a ten ns half width power pulse peaking above one terrawatt were obtained. MITE is a module being investigated for use in the Electron Beam Fusion Accelerator and will be used to test the effects of short pulses propagating down vacuum transmission lines

  19. A polymer electrolyte fuel cell stack for stationary power generation from hydrogen fuel

    Wilson, M.S.; Moeller-Holst, S.; Webb, D.M.; Zawodzinski, C.; Gottesfeld, S. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.


    The objective is to develop and demonstrate a 4 kW, hydrogen-fueled polymer electrolyte fuel cell (PEFC) stack, based on non-machined stainless steel hardware and on membrane/electrode assemblies (MEAs) of low catalyst loadings. The stack is designed to operate at ambient pressure on the air-side and can accommodate operation at higher fuel pressures, if so required. This is to be accomplished by working jointly with a fuel cell stack manufacturer, based on a CRADA. The performance goals are 57% energy conversion efficiency hydrogen-to-electricity (DC) at a power density of 0.9 kW/liter for a stack operating at ambient inlet pressures. The cost goal is $600/kW, based on present materials costs.

  20. Generation of electrical power

    A heat-to-electricity converter is disclosed which includes a radioactive heat source and a thermoelectric element of relatively short overall length capable of delivering a low voltage of the order of a few tenths of a volt. Such a thermoelectric element operates at a higher efficiency than longer higher-voltage elements; for example, elements producing 6 volts. In the generation of required power, the thermoelectric element drives a solid-state converter which is controlled by input current rather than input voltage and operates efficiently for a high signal-plus-noise to signal ratio of current. The solid-state converter has the voltage gain necessary to deliver the required voltage at the low input of the thermoelectric element

  1. Power generation using an activated carbon and metal mesh cathode in a microbial fuel cell

    Zhang, Fang


    An inexpensive activated carbon (AC) air cathode was developed as an alternative to a platinum-catalyzed electrode for oxygen reduction in a microbial fuel cell (MFC). AC was cold-pressed with a polytetrafluoroethylene (PTFE) binder to form the cathode around a Ni mesh current collector. This cathode construction avoided the need for carbon cloth or a metal catalyst, and produced a cathode with high activity for oxygen reduction at typical MFC current densities. Tests with the AC cathode produced a maximum power density of 1220 mW/m2 (normalized to cathode projected surface area; 36 W/m3 based on liquid volume) compared to 1060 mW/m2 obtained by Pt catalyzed carbon cloth cathode. The Coulombic efficiency ranged from 15% to 55%. These findings show that AC is a cost-effective material for achieving useful rates of oxygen reduction in air cathode MFCs. © 2009 Elsevier B.V. All rights reserved.

  2. Study of a small heat and power PEM fuel cell system generator

    Hubert, Charles-Emile; Achard, Patrick; Metkemeijer, Rudolf

    A micro-cogenerator based on a natural gas reformer and a PEMFC is studied in its entirety, pointing out the links between different sub-systems. The study is conducted within the EPACOP project, which aims at testing PEMFC systems on user sites to evaluate development and acceptance of this technology for small stationary applications. Five units were installed from November 2002 to May 2003 and have been operated until now, in real life conditions. They deliver up to 4 kW of AC power and about 6 kW of heat. Center for Energy and Processes (CEP), one of the scientific partners, processes and analyses the experimental data from the five units, running in different regions of France. This database and the study of the flowsheet enable to propose changes to enhance the efficiency of the system composed of a steam reforming, a shift and a preferential oxidation reactor, a fuel cell stack and heat exchangers. The steady state modelling and optimisation of the system is done with Thermoptim ®, a software developed within CEP for applied thermodynamics. At constant power, main targets are to decrease natural gas consumption, to increase heat recovery and to improve the water balance. This study is made using the pinch point analysis, at full load and partial load. Main results of this study are different system configurations that allow improvement of gross electrical and thermal efficiency and enable to obtain a positive water balance.

  3. Power generation using carbon mesh cathodes with different diffusion layers in microbial fuel cells

    Luo, Yong


    An inexpensive carbon material, carbon mesh, was examined to replace the more expensive carbon cloth usually used to make cathodes in air-cathode microbial fuel cells (MFCs). Three different diffusion layers were tested using carbon mesh: poly(dimethylsiloxane) (PDMS), polytetrafluoroethylene (PTFE), and Goretex cloth. Carbon mesh with a mixture of PDMS and carbon black as a diffusion layer produced a maximum power density of 1355 ± 62 mW m -2 (normalized to the projected cathode area), which was similar to that obtained with a carbon cloth cathode (1390 ± 72 mW m-2). Carbon mesh with a PTFE diffusion layer produced only a slightly lower (6.6%) maximum power density (1303 ± 48 mW m-2). The Coulombic efficiencies were a function of current density, with the highest value for the carbon mesh and PDMS (79%) larger than that for carbon cloth (63%). The cost of the carbon mesh cathode with PDMS/Carbon or PTFE (excluding catalyst and binder costs) is only 2.5% of the cost of the carbon cloth cathode. These results show that low cost carbon materials such as carbon mesh can be used as the cathode in an MFC without reducing the performance compared to more expensive carbon cloth. © 2011 Elsevier B.V.

  4. Global Assessment of Hydrogen Technologies – Task 5 Report Use of Fuel Cell Technology in Electric Power Generation

    Fouad, Fouad H.; Peters, Robert W.; Sisiopiku, Virginia P.; Sullivan Andrew J.; Ahluwalia, Rajesh K.


    The purpose of this work was to assess the performance of high temperature membranes and observe the impact of different parameters, such as water-to-carbon ratio, carbon formation, hydrogen formation, efficiencies, methane formation, fuel and oxidant utilization, sulfur reduction, and the thermal efficiency/electrical efficiency relationship, on fuel cell performance. A 250 KW PEM fuel cell model was simulated [in conjunction with Argonne National Laboratory (ANL) with the help of the fuel cell computer software model (GCtool)] which would be used to produce power of 250 kW and also produce steam at 120oC that can be used for industrial applications. The performance of the system was examined by estimating the various electrical and thermal efficiencies achievable, and by assessing the effect of supply water temperature, process water temperature, and pressure on thermal performance. It was concluded that increasing the fuel utilization increases the electrical efficiency but decreases the thermal efficiency. The electrical and thermal efficiencies are optimum at ~85% fuel utilization. The low temperature membrane (70oC) is unsuitable for generating high-grade heat suitable for useful cogeneration. The high temperature fuel cells are capable of producing steam through 280oC that can be utilized for industrial applications. Increasing the supply water temperature reduces the efficiency of the radiator. Increasing the supply water temperature beyond the dew point temperature decreases the thermal efficiency with the corresponding decrease in high-grade heat utilization. Increasing the steam pressure decreases the thermal efficiency. The environmental impacts of fuel cell use depend upon the source of the hydrogen rich fuel used. By using pure hydrogen, fuel cells have virtually no emissions except water. Hydrogen is rarely used due to problems with storage and transportation, but in the future, the growth of a “solar hydrogen economy” has been projected

  5. Gearless wind power generator

    Soederlund, L.; Ridanpaeae, P.; Vihriaelae, H.; Peraelae, R. [Tampere Univ. of Technology (Finland). Lab. of Electricity and Magnetism


    In the project a 100 kW axial flux permanent magnet wind power generator has been designed. The toroidal stator with air gap winding is placed between two rotating discs with permanent magnets. The magnet material is NdBFe due to its excellent magnetic properties compared to other materials. This type of topology enables a very large number of poles compared to conventional machine of the same size. A large number of poles is required to achieve a low rotational speed and consequently a direct driven system. The stator winding is formed by rectangular coils. The end winding is very short leading to small resistive losses. On the other hand, the absence of iron teeth causes eddy current losses in the conductors. These can be restricted to an acceptable level by keeping the wire diameter and flux density small. This means that the number of phases should be large. Several independent three phase systems may be used. The toothless stator also means that the iron losses are small and there exists no cogging torque

  6. Solar thermal aided power generation

    Fossil fuel based power generation is and will still be the back bone of our world economy, albeit such form of power generation significantly contributes to global CO2 emissions. Solar energy is a clean, environmental friendly energy source for power generation, however solar photovoltaic electricity generation is not practical for large commercial scales due to its cost and high-tech nature. Solar thermal is another way to use solar energy to generate power. Many attempts to establish solar (solo) thermal power stations have been practiced all over the world. Although there are some advantages in solo solar thermal power systems, the efficiencies and costs of these systems are not so attractive. Alternately by modifying, if possible, the existing coal-fired power stations to generate green sustainable power, a much more efficient means of power generation can be reached. This paper presents the concept of solar aided power generation in conventional coal-fired power stations, i.e., integrating solar (thermal) energy into conventional fossil fuelled power generation cycles (termed as solar aided thermal power). The solar aided power generation (SAPG) concept has technically been derived to use the strong points of the two technologies (traditional regenerative Rankine cycle with relatively higher efficiency and solar heating at relatively low temperature range). The SAPG does not only contribute to increase the efficiencies of the conventional power station and reduce its emission of the greenhouse gases, but also provides a better way to use solar heat to generate the power. This paper presents the advantages of the SAPG at conceptual level.

  7. Power Generation Characteristics of Solid Oxide Fuel Cells Operated with Simulated Coal Gas

    Tsujimoto, K.; Uchida, Y.; Sasaki, K.; Susuki, K.; Hori, Y.-I.; Teraoka, Y.; Eguchi, K.; Ueno, A.; Hiwatashi, K.-I.; Aizawa, M.


    Power generation characteristics of SOFCs are studied for simulated coal gas, consisting mainly of CO, H{sub 2}, H{sub 2}O, and carrier gas. Current- voltage characteristics were measured as a function of H{sub 2}-to-CO ratio. The SOFC voltage only slightly decreased with increasing CO concentration. The dependence of H{sub 2}-to-CO ratio on SOFC performance was analyzed by impedance spectroscopy. We have found that the current-voltage characteristics depend on the kind of carrier gas, indicating the importance of gas diffusion in porous anodes for anodic polarization. The influence of H{sub 2}S, one of the typical impurities in coal gas, to SOFC performance were measured as a function of H{sub 2}S concentration, H{sub 2}-to-CO ratio and operating temperature. The SOFC voltage decreased, when H{sub 2}S was added to the fuel. The voltage drop increased with increasing H{sub 2}S concentration. In addition, at a low operational temperature and/or a high CO concentration, the influence of H{sub 2}S became very significant. (author)

  8. Trace heavy metal ions promoted extracellular electron transfer and power generation by Shewanella in microbial fuel cells.

    Xu, Yu-Shang; Zheng, Tao; Yong, Xiao-Yu; Zhai, Dan-Dan; Si, Rong-Wei; Li, Bing; Yu, Yang-Yang; Yong, Yang-Chun


    Although microbial fuel cells (MFCs) is considered as one of the most promising technology for renewable energy harvesting, low power output still accounts one of the bottlenecks and limits its further development. In this work, it is found that Cu(2+) (0.1μgL(-1)-0.1mgL(-1)) or Cd(2+) (0.1μgL(-1)-1mgL(-1)) significantly improve the electricity generation in MFCs. The maximum power output achieved with trace level of Cu(2+) (∼6nM) or Cd(2+) (∼5nM) is 1.3 times and 1.6 times higher than that of the control, respectively. Further analysis verifies that addition of Cu(2+) or Cd(2+) effectively improves riboflavin production and bacteria attachment on the electrode, which enhances bacterial extracellular electron transfer (EET) in MFCs. These results unveil the mechanism for power output enhancement by Cu(2+) or Cd(2+) addition, and suggest that metal ion addition should be a promising strategy to enhance EET as well as power generation of MFCs. PMID:27038263

  9. Sustainable Power Generation in Continuous Flow Microbial Fuel Cell Treating Actual Wastewater: Influence of Biocatalyst Type on Electricity Production

    Zainab Z. Ismail


    Full Text Available Microbial fuel cells (MFCs have the potential to simultaneously treat wastewater for reuse and to generate electricity. This study mainly considers the performance of an upflow dual-chambered MFC continuously fueled with actual domestic wastewater and alternatively biocatalyzed with aerobic activated sludge and strain of Bacillus Subtilis. The behavior of MFCs during initial biofilm growth and characterization of anodic biofilm were studied. After 45 days of continuous operation, the biofilms on the anodic electrode were well developed. The performance of MFCs was mainly evaluated in terms of COD reductions and electrical power output. Results revealed that the COD removal efficiency was 84% and 90% and the stabilized power outputs were clearly observed achieving a maximum value of 120 and 270 mW/m2 obtained for MFCs inoculated with mixed cultures and Bacillus Subtilis strain, respectively.

  10. Power generation costs. Coal - nuclear power

    This supplement volume contains 17 separate chapters investigating the parameters which determine power generation costs on the basis of coal and nuclear power and a comparison of these. A detailed calculation model is given. The complex nature of this type of cost comparison is shown by a review of selected parameter constellation for coal-fired and nuclear power plants. The most favourable method of power generation can only be determined if all parameters are viewed together. One quite important parameter is the load factor, or rather the hours of operation. (UA) 891 UA/UA 892 AMO

  11. CO2 Fixation, Lipid Production, and Power Generation by a Novel Air-Lift-Type Microbial Carbon Capture Cell System.

    Hu, Xia; Liu, Baojun; Zhou, Jiti; Jin, Ruofei; Qiao, Sen; Liu, Guangfei


    An air-lift-type microbial carbon capture cell (ALMCC) was constructed for the first time by using an air-lift-type photobioreactor as the cathode chamber. The performance of ALMCC in fixing high concentration of CO2, producing energy (power and biodiesel), and removing COD together with nutrients was investigated and compared with the traditional microbial carbon capture cell (MCC) and air-lift-type photobioreactor (ALP). The ALMCC system produced a maximum power density of 972.5 mW·m(-3) and removed 86.69% of COD, 70.52% of ammonium nitrogen, and 69.24% of phosphorus, which indicate that ALMCC performed better than MCC in terms of power generation and wastewater treatment efficiency. Besides, ALMCC demonstrated 9.98- and 1.88-fold increases over ALP and MCC in the CO2 fixation rate, respectively. Similarly, the ALMCC significantly presented a higher lipid productivity compared to those control reactors. More importantly, the preliminary analysis of energy balance suggested that the net energy of the ALMCC system was significantly superior to other systems and could theoretically produce enough energy to cover its consumption. In this work, the established ALMCC system simultaneously achieved the high level of CO2 fixation, energy recycle, and municipal wastewater treatment effectively and efficiently. PMID:26270956

  12. Hybrid Solid Oxide Fuel Cell and Thermoelectric Generator for Maximum Power Output in Micro-CHP Systems

    Rosendahl, L. A.; Mortensen, Paw V.; Enkeshafi, Ali A.


    One of the most obvious early market applications for thermoelectric generators (TEG) is decentralized micro combined heat and power (CHP) installations of 0.5 kWe to 5 kWe based on fuel cell technology. Through the use of TEG technology for waste heat recovery it is possible to increase the electricity production in micro-CHP systems by more than 15%, corresponding to system electrical efficiency increases of some 4 to 5 percentage points. This will make fuel cell-based micro-CHP systems very competitive and profitable and will also open opportunities in a number of other potential business and market segments which are not yet quantified. This paper quantifies a micro-CHP system based on a solid oxide fuel cell (SOFC) and a high-performance TE generator. Based on a 3 kW fuel input, the hybrid SOFC implementation boosts electrical output from 945 W to 1085 W, with 1794 W available for heating purposes.

  13. Hybrid Solid Oxide Fuel Cell and Thermoelectric Generator for Maximum Power Output in Micro-CHP Systems

    Rosendahl, Lasse; Mortensen, Paw Vestergård; Enkeshafi, Ali A.


    market segments which are not yet quantified. This paper quantifies a micro-CHP system based on a solid oxide fuel cell (SOFC) and a high-performance TE generator. Based on a 3 kW fuel input, the hybrid SOFC implementation boosts electrical output from 945 W to 1085 W, with 1794 W available for heating...... electricity production in micro-CHP systems by more than 15%, corresponding to system electrical efficiency increases of some 4 to 5 percentage points. This will make fuel cell-based micro-CHP systems very competitive and profitable and will also open opportunities in a number of other potential business and......One of the most obvious early market applications for thermoelectric generators (TEG) is decentralized micro combined heat and power (CHP) installations of 0.5 kWe to 5 kWe based on fuel cell technology. Through the use of TEG technology for waste heat recovery it is possible to increase the...

  14. Power Quality Improvement of a Distributed Generation Power System

    Panga Harish


    Full Text Available The aim of this work is to improve the power quality for Distributed Generation (DG with power storage system. Power quality is the combination of voltage quality and current quality. Power quality is the set of limits of electrical properties that allows electrical systems to function in their intended manner without significant loss of performance or life. The electrical power quality is more concerned issue. The main problems are stationery and transient distortions in the line voltage such as harmonics, flicker, swells, sags and voltage asymmetries. Distributed Generation (DG also called as site generation, dispersed generation, embedded generation, decentralized generation, decentralized energy or distributed energy, generates electricity from the many small energy sources. In recent years, micro electric power systems such as photovoltaic generation systems, wind generators and micro gas turbines, etc., have increased with the deregulation and liberalization of the power market. Under such circumstances the environment surrounding the electric power industry has become ever more complicated and provides high-quality power in a stable manner which becomes an important topic. Here DG is assumed to include Wind power Generation (WG and Fuel Cells (FC, etc. Advantages of this system are constant power supply, constant voltage magnitude, absence of harmonics insupply voltage, un-interrupted power supply. In this project the electric power qualities in two cases will be compared. Case I: With the storage battery when it is introduced. Case II: Without the storage battery. The storage battery executes the control that maintains the voltage in the power system. It will be found that the Electric power quality will be improved, when storage battery is introduced. The model system used in this Project work is composed of a Wind Turbine, an Induction Generator, Fuel Cells, An Inverter and a Storage Battery. A miniature Wind Power Generator is

  15. Performance analysis of an integrated biomass gasification and PEMFC (proton exchange membrane fuel cell) system: Hydrogen and power generation

    The PEMFC (proton exchange membrane fuel cell) is expected to play a significant role in next-generation energy systems. Because most hydrogen that is used as a fuel for PEMFCs is derived from the reforming of natural gas, the use of renewable energy sources such as biomass to produce this hydrogen offers a promising alternative. This study is focused on the performance analysis of an integrated biomass gasification and PEMFC system. The combined heat and power generation output of this integrated system is designed for residential applications, taking into account thermal and electrical demands. A flowsheet model of the integrated PEMFC system is developed and employed to analyze its performance with respect to various key operating parameters. A purification process consisting of a water–gas shift reactor and a preferential oxidation reactor is also necessary in order to reduce the concentration of CO in the synthesis gas to below 10 ppm for subsequent use in the PEMFC. The effect of load level on the performance of the PEMFC system is investigated. Based on an electrical load of 5 kW, it is found that the electrical efficiency of the PEMFC integrated system is 22%, and, when waste heat recovery is considered, the total efficiency of the PEMFC system is 51%. - Highlights: • Performance of a biomass gasification and PEMFC integrated system is analyzed. • A flowsheet model of the PEMFC integrated system is developed. • Effect of biomass sources and key parameters on hydrogen and power generation is presented. • The PEMFC integrated system is designed for small-scale power demand. • Effect of load changes on the performance of PEMFC is investigated

  16. Power Generation for River and Tidal Generators

    Muljadi, Eduard [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wright, Alan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gevorgian, Vahan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Donegan, James [Ocean Renewable Power Company (ORPC), Portland, ME (United States); Marnagh, Cian [Ocean Renewable Power Company (ORPC), Portland, ME (United States); McEntee, Jarlath [Ocean Renewable Power Company (ORPC), Portland, ME (United States)


    Renewable energy sources are the second largest contributor to global electricity production, after fossil fuels. The integration of renewable energy continued to grow in 2014 against a backdrop of increasing global energy consumption and a dramatic decline in oil prices during the second half of the year. As renewable generation has become less expensive during recent decades, and it becomes more accepted by the global population, the focus on renewable generation has expanded from primarily wind and solar to include new types with promising future applications, such as hydropower generation, including river and tidal generation. Today, hydropower is considered one of the most important renewable energy sources. In river and tidal generation, the input resource flow is slower but also steadier than it is in wind or solar generation, yet the level of water turbulent flow may vary from one place to another. This report focuses on hydrokinetic power conversion.

  17. RF power generation

    Carter, R G


    This paper reviews the main types of r.f. power amplifiers which are, or may be, used for particle accelerators. It covers solid-state devices, tetrodes, inductive output tubes, klystrons, magnetrons, and gyrotrons with power outputs greater than 10 kW c.w. or 100 kW pulsed at frequencies from 50 MHz to 30 GHz. Factors affecting the satisfactory operation of amplifiers include cooling, matching and protection circuits are discussed. The paper concludes with a summary of the state of the art for the different technologies.

  18. Power generation, operation and control

    Wood, Allen J; Sheblé, Gerald B


    Since publication of the second edition, there have been extensive changes in the algorithms, methods, and assumptions in energy management systems that analyze and control power generation. This edition is updated to acquaint electrical engineering students and professionals with current power generation systems. Algorithms and methods for solving integrated economic, network, and generating system analysis are provided. Also included are the state-of-the-art topics undergoing evolutionary change, including market simulation, multiple market analysis, multiple interchange contract analysis, c

  19. Monolithic solid oxide fuel cell technology advancement for coal-based power generation. Final report, September 1989--March 1994


    This project has successfully advanced the technology for MSOFCs for coal-based power generation. Major advances include: tape-calendering processing technology, leading to 3X improved performance at 1000 C; stack materials formulations and designs with sufficiently close thermal expansion match for no stack damage after repeated thermal cycling in air; electrically conducting bonding with excellent structural robustness; and sealants that form good mechanical seals for forming manifold structures. A stack testing facility was built for high-spower MSOFC stacks. Comprehensive models were developed for fuel cell performance and for analyzing structural stresses in multicell stacks and electrical resistance of various stack configurations. Mechanical and chemical compatibility properties of fuel cell components were measured; they show that the baseline Ca-, Co-doped interconnect expands and weakens in hydrogen fuel. This and the failure to develop adequate sealants were the reason for performance shortfalls in large stacks. Small (1-in. footprint) two-cell stacks were fabricated which achieved good performance (average area-specific-resistance 1.0 ohm-cm{sup 2} per cell); however, larger stacks had stress-induced structural defects causing poor performance.

  20. Fuel Cell Power Model Version 2: Startup Guide, System Designs, and Case Studies. Modeling Electricity, Heat, and Hydrogen Generation from Fuel Cell-Based Distributed Energy Systems

    Steward, D.; Penev, M.; Saur, G.; Becker, W.; Zuboy, J.


    This guide helps users get started with the U.S. Department of Energy/National Renewable Energy Laboratory Fuel Cell Power (FCPower) Model Version 2, which is a Microsoft Excel workbook that analyzes the technical and economic aspects of high-temperature fuel cell-based distributed energy systems with the aim of providing consistent, transparent, comparable results. This type of energy system would provide onsite-generated heat and electricity to large end users such as hospitals and office complexes. The hydrogen produced could be used for fueling vehicles or stored for later conversion to electricity.

  1. Continuous power generation and microbial community structure of the anode biofilms in a three-stage microbial fuel cell system

    Chung, Kyungmi; Okabe, Satoshi [Hokkaido Univ., Sapporo (Japan). Dept. of Urban and Environmental Engineering


    A mediator-less three-stage two-chamber microbial fuel cell (MFC) system was developed and operated continuously for more than 1.5 years to evaluate continuous power generation while treating artificial wastewater containing glucose (10 mM) concurrently. A stable power density of 28 W/m3 was attained with an anode hydraulic retention time of 4.5 h and phosphate buffer as the cathode electrolyte. An overall dissolved organic carbon removal ratio was about 85%, and coulombic efficiency was about 46% in this MFC system. We also analyzed the microbial community structure of anode biofilms in each MFC. Since the environment in each MFC was different due to passing on the products to the next MFC in series, the microbial community structure was different accordingly. The anode biofilm in the first MFC consisted mainly of bacteria belonging to the Gammaproteobacteria, identified as Aeromonas sp., while the Firmicutes dominated the anode biofilms in the second and third MFCs that were mainly fed with acetate. Cyclic voltammetric results supported the presence of a redox compound(s) associated with the anode biofilm matrix, rather than mobile (dissolved) forms, which could be responsible for the electron transfer to the anode. Scanning electron microscopy revealed that the anode biofilms were comprised of morphologically different cells that were firmly attached on the anode surface and interconnected each other with anchor-like filamentous appendages, which might support the results of cyclic voltammetry. (orig.)

  2. Maximum power output and load matching of a phosphoric acid fuel cell-thermoelectric generator hybrid system

    Chen, Xiaohang; Wang, Yuan; Cai, Ling; Zhou, Yinghui


    Based on the current models of phosphoric acid fuel cells (PAFCs) and thermoelectric generators (TGs), a new hybrid system is proposed, in which the effects of multi-irreversibilities resulting from the activation, concentration, and ohmic overpotentials in the PAFC, Joule heat and heat leak in the TG, finite-rate heat transfer between the TG and the heat reservoirs, and heat leak from the PAFC to the environment are taken into account. Expressions for the power output and efficiency of the PAFC, TG, and hybrid system are analytically derived and directly used to discuss the performance characteristics of the hybrid system. The optimal relationship between the electric currents in the PAFC and TG is obtained. The maximum power output is numerically calculated. It is found that the maximum power output density of the hybrid system will increase about 150 Wm-2, compared with that of a single PAFC. The problem how to optimally match the load resistances of two subsystems is discussed. Some significant results for practical hybrid systems are obtained.

  3. Sustainable energy recovery in wastewater treatment by microbial fuel cells: stable power generation with nitrogen-doped graphene cathode.

    Liu, Yuan; Liu, Hong; Wang, Chuan; Hou, Shuang-Xia; Yang, Nuan


    Microbial fuel cells (MFCs) recover energy sustainably in wastewater treatment. Performance of non-noble cathode catalysts with low cost in neutral medium is vital for stable power generation. Nitrogen-doped graphene (NG) as cathode catalyst was observed to exhibit high and durable activity at buffered pH 7.0 during electrochemical measurements and in MFCs with respect to Pt/C counterpart. Electrochemical measurements showed that the oxygen reduction reaction (ORR) on NG possessed sustained activity close to the state-of-art Pt/C in terms of onset potential and electron transfer number. NG-MFCs displayed maximum voltage output of 650 mV and maximum power density of 776 ± 12 mW m(-2), larger than 610 mV and 750 ± 19 mW m(-2) of Pt/C-MFCs, respectively. Furthermore, long-time test lasted over 90 days, during which the maximum power density of NG-MFCs declined by 7.6%, with stability comparable to Pt/C-MFCs. Structure characterization of NG implied that the relatively concentrated acidic oxygen-containing groups improved such long-time stability by repelling the protons due to the same electrostatic force, and thus the C-N active centers for ORR were left undestroyed. These findings demonstrated the competitive advantage of NG to advance the application of MFCs for recovering biomass energy in treatment of wastewater with neutral pH. PMID:24219223

  4. An investigation of a carbon dioxide-based fuel cell system as a power generation alternative for Mars exploration applications

    Salinas Mejia, Oscar Roberto

    The possibility of using a bifunctional carbon dioxide-based fuel cell system as the core of a propulsion system for a Mars exploration rotorcraft is investigated here. This concept involves the production of electricity by a stack of fuel cells that rely on carbon monoxide as the fuel and oxygen as the oxidizer. These two reactants are harvested from the Martian atmosphere by employing the same stack of cells as an electrolyzing unit. The general objectives of this research are to: prove the feasibility of the concept, produce a comprehensive model that allows the prediction of performance, and offer recommendations for the successful implementation of the concept. In this work, it is pointed out and demonstrated that, at least in theory, the overall electrochemical reaction required by this concept can be achieved by transporting hydrogen protons, hydroxyl radicals, carbonate radicals, or oxygen ions between the electrodes. Complete sets of reactions are prescribed for different types of fuel cells. Anodic and cathodic reactions are presented for acid, alkaline, carbonate, and solid oxide electrolytes. Subsequently, a more detailed consideration of all relevant phenomena is done by coupling elements of chemical kinetics, electrodics, electrochemistry, and thermodynamics with experimental data, to complete the demonstration of the feasibility of the carbon dioxide-based bifunctional fuel cell system. The understanding and inclusion of key processes and mechanisms allows the construction of a model that predicts the performance of the power generation subsystem advocated here. The model adopted in this work couples mechanistics with elements derived from the application of linear regression modeling techniques. Mechanistics are used to determine: thermodynamic equilibrium potential, overvoltages due to activation, ohmic resistance, and mass transport. This approach is empirical in part because the numerical parametric expressions suggested here have to be precised

  5. Self-stacked submersible microbial fuel cell (SSMFC) for improved remote power generation from lake sediments

    Zhang, Yifeng; Angelidaki, Irini


    external resistance (≤400 Ω in this study) was applied. In addition, the internal resistance and OCV were the most important parameters for predicting which cell unit had the highest probability to undergo voltage reversal. Use of a capacitor was found to be an effective way to prevent voltage reversal and...

  6. Solar Power Generation Development

    Robert L. Johnson Jr.; Gary E. Carver


    This project centered on creating a solar cell prototype enabling significant reductions in module cost and increases in module efficiency. Low cost was addressed by using plentiful organic materials that only comprise 16% of the total module cost, and by leveraging building integrated PV concepts that reduce the cost of key module components to zero. High efficiency was addressed by implementing multiband organic PV, low cost spectral splitting, and possibly integrating photovoltaic and photothermal mechanisms. This research has contributed to the design of multiband organic PV, and the sealing of organic PV cells. If one assumes that the aggregate multiband efficiency can reach 12%, projected cost would be $0.97/W. If the sealing technology enables 10 to 20 year lifetimes, the LCOE will match that of domestic coal. The final report describes progress towards these goals.

  7. Power generation, operation, and control

    Wood, Allen J


    A comprehensive text on the operation and control of power generation and transmission systems In the ten years since Allen J. Wood and Bruce F. Wollenberg presented their comprehensive introduction to the engineering and economic factors involved in operating and controlling power generation systems in electric utilities, the electric power industry has undergone unprecedented change. Deregulation, open access to transmission systems, and the birth of independent power producers have altered the structure of the industry, while technological advances have created a host of new opportunities

  8. Nuclear power generation

    The case for nuclear power, from both a world and a British standpoint, is first discussed, with particular reference to oil supply and demand. It is considered that oil and gas should in future be used as a feedstock for the chemical industry, for transportation purposes, and as a starting point for protein food for animals and later for humans; to squander so much by burning simply as a crude fuel cannot be right. It is considered that Britain should continue constructing nuclear stations at a steady modest rate, and that the fast reactor should receive increasing attention, despite the anti-nuclear lobby. The case for the fast breeder reactor is discussed in detail, including its development at UKAEA Harwell and Dounreay. Accusations against the fast reactor are considered, particularly those concerned with safety, and with the use or misuse of Pu. Public debates are discussed. (U.K.)

  9. Nuclear power generation modern power station practice


    Nuclear Power Generation focuses on the use of nuclear reactors as heat sources for electricity generation. This volume explains how nuclear energy can be harnessed to produce power by discussing the fundamental physical facts and the properties of matter underlying the operation of a reactor. This book is comprised of five chapters and opens with an overview of nuclear physics, first by considering the structure of matter and basic physical concepts such as atomic structure and nuclear reactions. The second chapter deals with the requirements of a reactor as a heat source, along with the diff

  10. Nuclear power generation cost methodology

    A simplified calculational procedure for the estimation of nuclear power generation cost is outlined. The report contains a discussion of the various components of power generation cost and basic equations for calculating that cost. An example calculation is given. The basis of the fixed-charge rate, the derivation of the levelized fuel cycle cost equation, and the heavy water charge rate are included as appendixes

  11. Intermittent contact of fluidized anode particles containing exoelectrogenic biofilms for continuous power generation in microbial fuel cells

    Liu, Jia


    Current generation in a microbial fuel cell can be limited by the amount of anode surface area available for biofilm formation, and slow substrate degradation kinetics. Increasing the anode surface area can increase the amount of biofilm, but performance will improve only if the anode material is located near the cathode to minimize solution internal resistance. Here we demonstrate that biofilms do not have to be in constant contact with the anode to produce current in an MFC. Granular activated carbon particles enriched with exoelectrogenic biofilm are fluidized (by stirring) in the anode chamber of the MFC, resulting in only intermittent contact between the particles and the anode current collector. The maximum power density generated is 951 ± 10 mW m-2, compared to 813 ± 2 mW m-2 for the control without stirring (packed bed), and 525 ± 1 mW m-2 in the absence of GAC particles and without stirring. GAC-biofilm particles demonstrate capacitor-like behavior, but achieve nearly constant discharge conditions due to the large number of particles that contact the current collector. These results provide proof of concept for the development of flowable electrode reactors, where anode biofilms can be electrically charged in a separate storage tank and then rapidly discharged in compact anode chambers. © 2014 Elsevier B.V. All rights reserved.

  12. Exergetic and exergoeconomic evaluation of a solid-oxide fuel-cell-based combined heat and power generation system

    Highlights: • Exergy-based evaluations of a SOFC-based power generation system have been made. • The exergy of fuel and the exergy of product are rigorously defined. • Cost balance and auxiliary equations are formulated for the exergoeconomic analysis. • The cost structure of the overall system has been analyzed. • Suggestions are made for improving the cost effectiveness of the entire system. - Abstract: Exergetic and exergoeconomic evaluations have been carried out for a 100 kW-class solid-oxide fuel-cell-based combined heat and power generation system, to find out the measures that would improve its efficiency, and, more importantly, its cost effectiveness. The exergoeconomic analysis is an appropriate combination of an exergetic analysis and an economic analysis; through exergoeconomics, we obtain the real cost associated with each stream and with the inefficiencies within each component in a system. For the analyses, the exergies of fuel and the exergies of product for all components have been defined. Subsequently, the exergetic efficiency of each component has been evaluated. By combining the results obtained from an economic analysis with the results of the exergetic analysis, the cost structure of the overall system has been figured out. The components, showing higher exergoeconomic factors such as SOFC stack, fuel blower, heat recovery water pump, and inverter, need reduction of investment cost, even if the associated efficiency would decreased because of this cost reduction. For the components, exhibiting lower exergoeconomic factors such as integrated reformer, fuel/water pre-heater, and air pre-heater, the main focus should be on efficiency improvements, even if higher investment expenditures would be associated with such improvements

  13. Powerful microsecond voltage pulse generator

    A microsecond voltage pulse generator, designed for investigations of high-power electron and ion beams generation in diode systems connected in parallel into a circuit with an inductive storage and plasma-erosion switch, is described. The generator consists of eight parallel pulsed voltage generators with 12 stages in each, assembled according to the Arkadiev-Marx scheme with two capacitors in each stage. The generator total energy at charged voltage of 80kV is 250 kJ. The main generator parameters are the following: the proper inductance is ≅0.7μH, wave resistance is ≅1.140hm, oscillation period is ≅3.83μs, attenuation is ≅105s-1. The results of the first experiments on generation of a microsecond high-current relativistic electron beam in a coaxial magnetically insulated diode are described

  14. Taming power: Generative historical consciousness.

    Winter, David G


    Power is a necessary dimension of all human enterprises. It can inspire and illuminate, but it can also corrupt, oppress, and destroy. Therefore, taming power has been a central moral and political question for most of human history. Writers, theorists, and researchers have suggested many methods and mechanisms for taming power: through affiliation and love, intellect and reason, responsibility, religion and values, democratic political structures, and separation of powers. Historical examples and social science research suggest that each has some success, but also that each is vulnerable to being hijacked by power itself. I therefore introduce generative historical consciousness (GHC) as a concept and measure that might help to secure the benefits of power while protecting against its outrages and excesses. I conclude by discussing the role that GHC may have played in the peaceful resolution of the Cuban Missile Crisis of 1962. PMID:26011649

  15. Power Generation from Coal 2011



    This report focuses mainly on developments to improve the performance of coal-based power generation technologies, which should be a priority -- particularly if carbon capture and storage takes longer to become established than currently projected. A close look is taken of the major ongoing developments in process technology, plant equipment, instrumentation and control. Coal is an important source of energy for the world, particularly for power generation. To meet the growth in demand for energy over the past decade, the contribution from coal has exceeded that of any other energy source. Additionally, coal has contributed almost half of total growth in electricity over the past decade. As a result, CO2 emissions from coal-fired power generation have increased markedly and continue to rise. More than 70% of CO2 emissions that arise from power generation are attributed to coal. To play its role in a sustainable energy future, its environmental footprint must be reduced; using coal more efficiently is an important first step. Beyond efficiency improvement, carbon capture and storage (CCS) must be deployed to make deep cuts in CO2 emissions. The need for energy and the economics of producing and supplying it to the end-user are central considerations in power plant construction and operation. Economic and regulatory conditions must be made consistent with the ambition to achieve higher efficiencies and lower emissions. In essence, clean coal technologies must be more widely deployed.

  16. Solar power generation technology, new concepts & policy

    Reddy, P Jayarama


    This book provides an overview of the current state of affairs in the field of solar power engineering from a global perspective. In four parts, this well-researched volume informs about (1) established solar PV (photovoltaic) technologies; (2) third-generation PV technologies based on new materials with potential for low-cost large-scale production; (3) solar cell technology based on new (third-generation) concepts such as quantum dot solar cells and nano wire solar cells using silicon and compound semiconductors; and (4) economic implications and effects, as well as policies and incentives i

  17. Power generation from solid fuels

    Spliethoff, Hartmut


    Power Generation from Solid Fuels introduces the different technologies to produce heat and power from solid fossil (hard coal, brown coal) and renewable (biomass, waste) fuels, such as combustion and gasification, steam power plants and combined cycles etc. The book discusses technologies with regard to their efficiency, emissions, operational behavior, residues and costs. Besides proven state of the art processes, the focus is on the potential of new technologies currently under development or demonstration. The main motivation of the book is to explain the technical possibilities for reduci

  18. Generation 'Next' and nuclear power

    My generation was labeled by Russian mass media as generation 'Next.' My technical education is above average. My current position is as a mechanical engineer in the leading research and development institute for Russian nuclear engineering for peaceful applications. It is noteworthy to point out that many of our developments were really first-of-a-kind in the history of engineering. However, it is difficult to grasp the importance of these accomplishments, especially since the progress of nuclear technologies is at a standstill. Can generation 'Next' be independent in their attitude towards nuclear power or shall we rely on the opinions of elder colleagues in our industry? (authors)

  19. Power generation with sour gas

    Williams, B. [Mercury Energy, Calgary, AB (Canada)


    This paper presents an overview of Mercury Energy and its experience with microturbines for power generation with sour gas. The economics of sour gas versus sweet gas were presented along with operational considerations for gas turbines and reciprocating engines. Mercury Electric was formed in 1995 as an independent power producer using waste gas. It tested the prototype and early production of microturbines for sour gas. Mercury Electric subsequently became Mercury Energy in 2002, and is now focused on exploration and production. The installation of the Gainsborough Battery in Saskatchewan offered insight into exhaust stacks, corrosion on microturbine exhaust enclosure, and the premium for low volume, sour trim compression required for hydrogen sulfide fuel gas. It was noted that small scale (less than 500 kW) sour gas fired generation is not competitive with grid power, but it may be viable for remote areas where grid power is not available. Larger scale (more than 1 MW) sour gas fired generation can compete with grid power under the right conditions. 2 tabs., 1 fig.

  20. Future Photovoltaic Power Generation for Space-Based Power Utilities

    Bailey, S.; Landis, G.; Raffaelle, R.; Hepp, A.


    A recent NASA program, Space Solar Power Exploratory Research and Technology (SERT), investigated the technologies needed to provide cost-competitive ground baseload electrical power from space based solar energy conversion. This goal mandated low cost, light weight gigawatt (GW) power generation. Investment in solar power generation technologies would also benefit high power military, commercial and science missions. These missions are generally those involving solar electric propulsion, surface power systems to sustain an outpost or a permanent colony on the surface of the moon or mars, space based lasers or radar, or as large earth orbiting power stations which can serve as central utilities for other orbiting spacecraft, or as in the SERT program, potentially beaming power to the earth itself. This paper will discuss requirements for the two latter options, the current state of the art of space solar cells, and a variety of both evolving thin film cells as well as new technologies which may impact the future choice of space solar cells for a high power mission application. The space world has primarily transitioned to commercially available III-V (GaInP/GaAs/Ge) cells with 24-26% air mass zero (AMO) efficiencies. Research in the III-V multi-junction solar cells has focused on fabricating either lattice-mismatched materials with optimum stacking bandgaps or new lattice matched materials with optimum bandgaps. In the near term this will yield a 30% commercially available space cell and in the far term possibly a 40% cell. Cost reduction would be achieved if these cells could be grown on a silicon rather than a germanium substrate since the substrate is ~65% of the cell cost or, better yet, on a polyimide or possibly a ceramic substrate. An overview of multi-junction cell characteristics will be presented here. Thin film cells require substantially less material and have promised the advantage of large area, low cost manufacturing. However, space cell requirements

  1. Preliminary study of the influence of solar cell degradation due to ESD on solar array power generation

    Okumura, Teppei; Toyoda, Kazuhiro; Kawakita, Shiro; Imaizumi, Mitsuru; 奥村 哲平; 豊田 和弘; 川北 史朗; 今泉 充; Cho, Mengu


    In space, an ElectroStatic Discharge (ESD) can occur on a solar array due to the plasma interaction. One of the issues of ESD is the degradation of solar cell electric performance. To establish the power degradation estimation method due to ESD in solar arrays, light current-voltage characteristics are evaluated in the current value at maximum power. From the results of the calculation, InGaP/GaAs/Ge solar arrays potentially suffer more serious power degradation than Si solar array.

  2. Fuel cell generator

    A high temperature solid electrolyte fuel cell generator comprising a housing means defining a plurality of chambers including a generator chamber and a combustion products chamber, a porous barrier separating the generator and combustion product chambers, a plurality of elongated annular fuel cells each having a closed end and an open end with the open ends disposed within the combustion product chamber, the cells extending from the open end through the porous barrier and into the generator chamber, a conduit for each cell, each conduit extending into a portion of each cell disposed within the generator chamber, each conduit having means for discharging a first gaseous reactant within each fuel cell, exhaust means for exhausting the combustion product chamber, manifolding means for supplying the first gaseous reactant to the conduits with the manifolding means disposed within the combustion product chamber between the porous barrier and the exhaust means and the manifolding means further comprising support and bypass means for providing support of the manifolding means within the housing while allowing combustion products from the first and a second gaseous reactant to flow past the manifolding means to the exhaust means, and means for flowing the second gaseous reactant into the generator chamber

  3. Water reactive hydrogen fuel cell power system

    Wallace, Andrew P; Melack, John M; Lefenfeld, Michael


    A water reactive hydrogen fueled power system includes devices and methods to combine reactant fuel materials and aqueous solutions to generate hydrogen. The generated hydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueled power system includes a fuel cell, a water feed tray, and a fuel cartridge to generate power for portable power electronics. The removable fuel cartridge is encompassed by the water feed tray and fuel cell. The water feed tray is refillable with water by a user. The water is then transferred from the water feed tray into a fuel cartridge to generate hydrogen for the fuel cell which then produces power for the user.

  4. Next Generation Geothermal Power Plants

    Brugman, John; Hattar, Mai; Nichols, Kenneth; Esaki, Yuri


    A number of current and prospective power plant concepts were investigated to evaluate their potential to serve as the basis of the next generation geothermal power plant (NGGPP). The NGGPP has been envisaged as a power plant that would be more cost competitive (than current geothermal power plants) with fossil fuel power plants, would efficiently use resources and mitigate the risk of reservoir under-performance, and minimize or eliminate emission of pollutants and consumption of surface and ground water. Power plant concepts were analyzed using resource characteristics at ten different geothermal sites located in the western United States. Concepts were developed into viable power plant processes, capital costs were estimated and levelized busbar costs determined. Thus, the study results should be considered as useful indicators of the commercial viability of the various power plants concepts that were investigated. Broadly, the different power plant concepts that were analyzed in this study fall into the following categories: commercial binary and flash plants, advanced binary plants, advanced flash plants, flash/binary hybrid plants, and fossil/geothed hybrid plants. Commercial binary plants were evaluated using commercial isobutane as a working fluid; both air-cooling and water-cooling were considered. Advanced binary concepts included cycles using synchronous turbine-generators, cycles with metastable expansion, and cycles utilizing mixtures as working fluids. Dual flash steam plants were used as the model for the commercial flash cycle. The following advanced flash concepts were examined: dual flash with rotary separator turbine, dual flash with steam reheater, dual flash with hot water turbine, and subatmospheric flash. Both dual flash and binary cycles were combined with other cycles to develop a number of hybrid cycles: dual flash binary bottoming cycle, dual flash backpressure turbine binary cycle, dual flash gas turbine cycle, and binary gas turbine

  5. Electric power generation in China

    In 1985, some 25% of all Chinese were still without electricity (totalling some 260 million people exclamation point). In 1990. per capita electricity consumption was 520 kWh/year, about one-fourth of the world average. Yet all this is changing very quickly. As part of the government's reform and open policy, designed to speed economic development, the electric power industry is being challenged to match the economic growth rate one-for-one. The planned annual growth of installed generating capacity this decade is 9%. Newly added capacity is expected to be between 13 and 15 GW per year. (In 1991, installed capacity was 151 GW, while total electric energy produced was 677.5 TWh - enough to place fourth in production behind the United States, Japan and Germany.) To achieve these goals, the government is working to increase the number of financing channels available for new electric power construction, and to grant more decision-making power to electric power enterprises. Efforts are also under way to improve energy conservation, enhance international exchange and speed up the electrification of rural areas. This paper takes a look at the various power generation activities in China that are based on diesel, gas and gas turbine engines. 10 figs

  6. Adoption of nuclear power generation

    This article develops a model of the innovation-adoption decision. The model allows the economic situation of a utility and its perception of uncertainty associated with an innovation to affect the probability of adopting it. This model is useful when uncertainties affecting decisions about adoption persist throughout the diffusion process, thereby making the usual adoption model implicit in rate-of-diffusion studies inappropriate. An empirical test of the model finds that firm size, power pool size, and selected aspects of uncertainty about the innovation are significant predictors of US utility companies' decisions on whether or not to adopt nuclear power generation. 17 references, 2 tables

  7. Power generation in microbial fuel cell fed with post methanation distillery effluent as a function of pH microenvironment.

    Kaushik, Anubha; Chetal, Anu


    The effect of anolyte and catholyte pH on power generation in an MFC using post methanation distillery effluent (PMDE) was studied in batch mode. Higher anodic pH (7-9) and low cathodic pH (2) were more favorable and at the optimal cathode:anode pH ratio of 2:8, power density attained was 0.457 W/m(3). An initial feed solution pH up to 10 was tolerated by the MFC. However, internal resistance increased 1.5 times and power density decreased by 60% at pH 10 as compared to that at pH 7, the normal anolyte pH. Internal resistance of the MFC was minimum (266 ohms) at cathodic pH 2, thus favoring better power generation. Under low cathodic and high anodic pH ratio of the MFC, a low internal resistance favored both high current density and power density. PMID:23994694

  8. The Development of Fuel Cell Technology for Electric Power Generation - From Spacecraft Applications to the Hydrogen Economy

    Scott, John H.


    The fuel cell uses a catalyzed reaction between a fuel and an oxidizer to directly produce electricity. Its high theoretical efficiency and low temperature operation made it a subject of much study upon its invention ca. 1900, but its relatively high life cycle costs kept it as "solution in search of a problem" for its first half century. The first problem for which fuel cells presented a cost effective solution was, starting in the 1960's that of a power source for NASA's manned spacecraft. NASA thus invested, and continues to invest, in the development of fuel cell power plants for this application. However, starting in the mid-1990's, prospective environmental regulations have driven increased governmental and industrial interest in "green power" and the "Hydrogen Economy." This has in turn stimulated greatly increased investment in fuel cell development for a variety of terrestrial applications. This investment is bringing about notable advances in fuel cell technology, but these advances are often in directions quite different from those needed for NASA spacecraft applications. This environment thus presents both opportunities and challenges for NASA's manned space program.

  9. Reference costs for power generation

    The first part of the 2003 study of reference costs for power generation has been completed. It was carried out by the General Directorate for Energy and Raw Materials (DGEMP) of the French Ministry of the Economy, Finance and Industry, with the collaboration of power-plant operators, construction firms and many other experts. A Review Committee of experts including economists (Forecasting Department, French Planning Office), qualified public figures, representatives of power-plant construction firms and operators, and non-governmental organization (NGO) experts, was consulted in the final phase. The study examines the costs of power generated by different methods (i.e. nuclear and fossil-fuel [gas-, coal-, and oil-fired] power plants) in the context of an industrial operation beginning in the year 2015. - The second part of the study relating to decentralized production methods (wind, photovoltaic, combined heat and power) is still in progress and will be presented at the beginning of next year. - 1. Study approach: The study is undertaken mainly from an investor's perspective and uses an 8% discount rate to evaluate the expenses and receipts from different years. In addition, the investment costs are considered explicitly in terms of interest during construction. - 2. Plant operating on a full-time basis (year-round): The following graph illustrates the main conclusions of the study for an effective operating period of 8000 hours. It can be seen that nuclear is more competitive than the other production methods for a year-round operation with an 8% discount rate applied to expenses. This competitiveness is even better if the costs related to greenhouse-gas (CO2) emission are taken into account in estimating the MWh cost price. Integrating the costs resulting from CO2 emissions by non-nuclear fuels (gas, coal), which will be compulsory as of 2004 with the transposition of European directives, increases the total cost per MWh of these power generation methods. Two

  10. Induction generator powered coaxial launchers

    Most coaxial accelerator concepts to date have used switched power supplies to energize coils in the vicinity of the projectile, or have tolerated a grossly oversized power supply which energizes all coils during the course of the launch. Coordination of the switching, while engineeringly possible, provides opportunities for failure which reduces the reliability of the system as compared to a passively activated system requiring no switching. Excitation of un-used sections of a launcher dramatically reduces launch efficiency, and increases both power supply and cooling requirements. A launcher design which avoids the need for switching and automatically excites only the windings in the vicinity of the projectile is presented in this paper. The energy store for the launcher consists of rotating induction machines. The excitation for the launcher is provided by an excitation winding on the projectile, which makes the projectile act like the rotor of a synchronous condenser. This combination of super-synchronous induction machines (the energy stores) and synchronous alternators (the projectile) is called an induction generator. This paper provides a description of the induction generator powered launcher concept, and investigates scaling laws to assess the applicability of this technology for tactical and space launch applications

  11. Fuel cells multi-stack power architectures and experimental validation of 1 kW parallel twin stack PEFC generator based on high frequency magnetic coupling dedicated to on board power unit

    This paper presents a study of a polymer electrolyte fuel cell (PEFC) multi-stack generator and its power electronic interface dedicated to an on board vehicle power unit. A parallel electric architecture has been designed and tested. First, a dynamic model of the PEFC stack, valid for high frequencies and compatible with power converter interactions, has been developed. This model is used for simulations of the global fuel cell and power converter behaviors. Second, an inventory of generic multi-stack fuel cells architectures is presented in order to couple electrically the fuel cell stacks to an on board DC bus (in series, parallel, through magnetic coupling..). This state of the art is completed by an overview of several candidate power converter topologies for fuel cells. Then, among all the possible technical solutions, an original power converter architecture using a high frequency planar transformer is proposed, which allows parallel and series magnetic couplings of two fuel cell stacks. Then, the study focuses on a first step, which is the association of two PEFC stacks. Such a structure, having good efficiency, is well adapted for testing and operation of fuel cells in normal and degraded working modes, which correspond to real constraints on board a vehicle. Finally, experimental validations on a 2 x 500 W twin stack PEFC with power converter interface demonstrate the technological feasibility for the embarked multi-stack fuel cells generator. The 1 kW power level chosen for the experimentation is close to that of a small on board PEFC auxiliary power unit (APU)

  12. Transforming Ontario's Power Generation Company

    The OPG Review Committee was formed by the Ontario Ministry of Energy to provide recommendations and advice on the future role of Ontario Power Generation Inc. (OPG) in the electricity sector. This report describes the future structure of OPG with reference to the appropriate corporate governance and senior management structure. It also discusses the potential refurbishing of the Pickering A nuclear generating Units 1, 2 and 3. The electricity system in Ontario is becoming increasingly fragile. The province relies heavily on electricity imports and the transmission system is being pushed to near capacity. Three nuclear generating units are out of service. The problems can be attributed to the fact that the electricity sector has been subjected to unpredictable policy changes for more than a decade, and that the largest electricity generator (OPG) has not been well governed. OPG has had frequent senior management change, accountability has been weak, and cost overruns have delayed the return to service of the Pickering nuclear power Unit 4. It was noted that the generating assets owned and operated by OPG are capable of providing more than 70 per cent of Ontario's electricity supply. Decisive action is needed now to avoid a potential supply shortage of about 5,000 to 7,000 megawatts by 2007. In its current state, OPG risks becoming a burden on ratepayers. Forty recommendations were presented, some of which suggest that OPG should become a rate-regulated commercial utility focused on running and maintaining its core generating assets. This would require that the government act as a shareholder, and the company operate like a commercial business. It was also emphasized that the market must be allowed to bring in new players. refs., tabs., figs

  13. Electric power generation the changing dimensions

    Tagare, D M


    "This book offers an analytical overview of established electric generation processes, along with the present status & improvements for meeting the strains of reconstruction. These old methods are hydro-electric, thermal & nuclear power production. The book covers climatic constraints; their affects and how they are shaping thermal production. The book also covers the main renewable energy sources, wind and PV cells and the hybrids arising out of these. It covers distributed generation which already has a large presence is now being joined by wind & PV energies. It covers their accommodation in the present system. It introduces energy stores for electricity; when they burst upon the scene in full strength are expected to revolutionize electricity production. In all the subjects covered, there are references to power marketing & how it is shaping production. There will also be a reference chapter on how the power market works"--Provided by publisher.

  14. New energy technologies for power generation

    Intensive R and D activity in the recent years is responsible for the development of various new technologies for power generation including fluidized bed combustion systems, gasifier-combined cycle plants, fuel cells and magneto-hydrodynamic power plants, advanced nuclear technologies such as fast-breeder reactor and fusion technology and renewable technologies such as solar, wind, hydro, geothermal, and ocean-thermal conversion plants. In this paper, the technical and economic facts regarding some of these technologies are briefly presented for the purpose of consistent technology evaluation and future planning for power generation. Most of these technologies are not yet commercialized or demonstrated and much uncertainty lies in any projections of their cost and performance data. For these technologies, the projections of cost and performance assume that the technology has already been successfully developed and is in a mature state of commercial use. (author)

  15. Treatment of seafood processing wastewater using upflow microbial fuel cell for power generation and identification of bacterial community in anodic biofilm.

    Jayashree, C; Tamilarasan, K; Rajkumar, M; Arulazhagan, P; Yogalakshmi, K N; Srikanth, M; Banu, J Rajesh


    Tubular upflow microbial fuel cell (MFC) utilizing sea food processing wastewater was evaluated for wastewater treatment efficiency and power generation. At an organic loading rate (OLR) of 0.6 g d(-1), the MFC accomplished total and soluble chemical oxygen demand (COD) removal of 83 and 95%, respectively. A maximum power density of 105 mW m(-2) (2.21 W m(-3)) was achieved at an OLR of 2.57 g d(-1). The predominant bacterial communities of anode biofilm were identified as RB1A (LC035455), RB1B (LC035456), RB1C (LC035457) and RB1E (LC035458). All the four strains belonged to genera Stenotrophomonas. The results of the study reaffirms that the seafood processing wastewater can be treated in an upflow MFC for simultaneous power generation and wastewater treatment. PMID:27254294

  16. Photovoltaic technologies for commercial power generation

    Photovoltaic power generation is an attractive source of energy since it involves the direct conversion of sunlight into electricity with no moving parts and no pollution. Following the demonstration of the first solar cell 35 years ago at Bell Laboratories, a steady stream of scientific and commercial progress has led to a rapid increase in applications in recent years. The first commercial application of solar cells occurred more than 20 years ago when they were used to supply power for space satellites, and even today photovoltaic arrays are used to supply electricity for most satellites and space probes. This paper reviews the status of the various photovoltaic technologies as well as present applications. The prospects for both distributed and central station grid-connected systems are discussed. The paper concludes with a discussion of the institutional and political factors that will affect the introduction of grid-connected photovoltaic power systems

  17. Photovoltaic technologies for commerical power generation

    The author reports photovoltaic power generation is an attractive source of energy since it involves the direct conversion of sunlight into electricity with no moving parts and no pollution. Following the demonstration of the first solar cell 35 years ago at Bell Laboratories, a steady stream of scientific and commercial progress has led to a rapid increase in applications in recent years. The first commercial application of solar cells occurred more than 20 years ago when they were used to supply power for space satellites, and even today photovoltaic arrays are used to supply electricity for most satellites and space probes. This paper reviews the status of the various photovoltaic technologies as well as present applications. The prospects for both distributed and central station grid-connected systems are discussed. The paper concludes with a discussion of the institutional and political factors that will affect the introduction of grid-connected photovoltaic power systems

  18. Gas-fired electric power generating technologies

    The workshop that was held in Madrid 25-27 May 1994 included participation by experts from 16 countries. They represented such diverse fields and disciplines as technology, governmental regulation, economics, and environment. Thus, the participants provided an excellent cross section of key areas and a diversity of viewpoints. At the workshop, a broad range of topics regarding gas-fired electric power generation was discussed. These included political, regulatory and financial issues as well as more specific technical questions regarding the environment, energy efficiency, advanced generation technologies and the status of competitive developments. Important technological advances in gas-based power and CHP technologies have already been achieved including higher energy efficiency and lower emissions, with further improvements expected in the near future. Advanced technology trends include: (a) The use of gas technology to reduce emissions from existing coal-fired power plants. (b) The wide-spread application of combined-cycle gas turbines in new power plants and the growing use of aero-derivative gas turbines in CHP applications. (c) Phosphoric acid fuel cells that are being introduced commercially. Their market penetration will grow over the next 10 years. The next generation of fuel cells (solid oxide and molten carbonate) is expected to enter the market around the year 2000. (EG)

  19. Performance of two different types of anodes in membrane electrode assembly microbial fuel cells for power generation from domestic wastewater

    Hays, Sarah


    Graphite fiber brush electrodes provide high surface areas for exoelectrogenic bacteria in microbial fuel cells (MFCs), but the cylindrical brush format limits more compact reactor designs. To enable MFC designs with closer electrode spacing, brush anodes were pressed up against a separator (placed between the electrodes) to reduce the volume occupied by the brush. Higher maximum voltages were produced using domestic wastewater (COD = 390 ± 89 mg L-1) with brush anodes (360 ± 63 mV, 1000 Ω) than woven carbon mesh anodes (200 ± 81 mV) with one or two separators. Maximum power densities were similar for brush anode reactors with one or two separators after 30 days (220 ± 1.2 and 240 ± 22 mW m-2), but with one separator the brush anode MFC power decreased to 130 ± 55 mW m-2 after 114 days. Power densities in MFCs with mesh anodes were very low (<45 mW m-2). Brush anodes MFCs had higher COD removals (80 ± 3%) than carbon mesh MFCs (58 ± 7%), but similar Coulombic efficiencies (8.6 ± 2.9% brush; 7.8 ± 7.1% mesh). These results show that compact (hemispherical) brush anodes can produce higher power and more effective domestic wastewater treatment than flat mesh anodes in MFCs. © 2011 Elsevier B.V. All rights reserved.

  20. Is it possible to design a portable power generator based on micro-solid oxide fuel cells? A finite volume analysis

    Pla, D.; Sánchez-González, A.; Garbayo, I.; Salleras, M.; Morata, A.; Tarancón, A.


    The inherent limited capacity of current battery technology is not sufficient for covering the increasing power requirements of widely extended portable devices. Among other promising alternatives, recent advances in the field of micro-Solid Oxide Fuel Cells (μ-SOFCs) converted this disruptive technology into a serious candidate to power next generations of portable devices. However, the implementation of single cells in real devices, i.e. μ-SOFC stacks coupled to the required balance-of-plant elements like fuel reformers or post combustors, still remains unexplored. This work aims addressing this system-level research by proposing a new compact design of a vertically stacked device fuelled with ethanol. The feasibility and design optimization for achieving a thermally self-sustained regime and a rapid and low-power consuming start-up is studied by finite volume analysis. An optimal thermal insulation strategy is defined to maintain the steady-state operation temperature of the μ-SOFC at 973 K and an external temperature lower than 323 K. A hybrid start-up procedure, based on heaters embedded in the μ-SOFCs and heat released by chemical reactions in the post-combustion unit, is analyzed allowing start-up times below 1 min and energy consumption under 500 J. These results clearly demonstrate the feasibility of high temperature μ-SOFC power systems fuelled with hydrocarbons for portable applications, therefore, anticipating a new family of mobile and uninterrupted power generators.

  1. Power Generation from Coal 2010



    Coal is the biggest single source of energy for electricity production and its share is growing. The efficiency of converting coal into electricity matters: more efficient power plants use less fuel and emit less climate-damaging carbon dioxide. This book explores how efficiency is measured and reported at coal-fired power plants. With many different methods used to express efficiency performance, it is often difficult to compare plants, even before accounting for any fixed constraints such as coal quality and cooling-water temperature. Practical guidelines are presented that allow the efficiency and emissions of any plant to be reported on a common basis and compared against best practice. A global database of plant performance is proposed that would allow under-performing plants to be identified for improvement. Armed with this information, policy makers would be in a better position to monitor and, if necessary, regulate how coal is used for power generation. The tools and techniques described will be of value to anyone with an interest in the more sustainable use of coal.

  2. Reactive power of the ozone generators

    The paper presents the analysis of the reactive power flow in the ozone generator power system and discusses some possibilities of its minimization. Discharge elements of the ozone generator comprise strong non-linear capacitive energy receiver and supply system should provide the ozone generator with the active power P necessary to carry out reactions in the inter-electrode zone, the reactive capacitive power Qc that is to generate electric field at the gap and the dielectric of the discharge elements and the distortion power QD due to the ozone generator non-linearity. The reactive power is provided to the circuit from the power network and the same amount is returned during every period of supply voltage resulting in the energy loss at the elements of the power system. Their minimizations in the ozone generators allow reducing power loss in the process of the ozone generation and improve overall efficiency of the system. (author)

  3. Electronic load for testing power generating devices

    Friedman, E. B.; Stepfer, G.


    Instrument tests various electric power generating devices by connecting the devices to the input of the load and comparing their outputs with a reference voltage. The load automatically adjusts until voltage output of the power generating device matches the reference.

  4. Performance of two different types of anodes in membrane electrode assembly microbial fuel cells for power generation from domestic wastewater

    Hays, Sarah; Zhang, Fang; Logan, Bruce E.


    Graphite fiber brush electrodes provide high surface areas for exoelectrogenic bacteria in microbial fuel cells (MFCs), but the cylindrical brush format limits more compact reactor designs. To enable MFC designs with closer electrode spacing, brush anodes were pressed up against a separator (placed between the electrodes) to reduce the volume occupied by the brush. Higher maximum voltages were produced using domestic wastewater (COD = 390 ± 89 mg L-1) with brush anodes (360 ± 63 mV, 1000 Ω) than woven carbon mesh anodes (200 ± 81 mV) with one or two separators. Maximum power densities were similar for brush anode reactors with one or two separators after 30 days (220 ± 1.2 and 240 ± 22 mW m-2), but with one separator the brush anode MFC power decreased to 130 ± 55 mW m-2 after 114 days. Power densities in MFCs with mesh anodes were very low (wastewater treatment than flat mesh anodes in MFCs.

  5. Numerical analysis of electrical power generation and internal reforming characteristics in seal-less disk-type solid oxide fuel cells

    Shimada, Takanobu; Momma, Akihiko; Takano, Kiyonami; Kato, Tohru

    For seal-less type solid oxide fuel cells, its power generation characteristics and distribution of the gas composition depend on not only the electrochemical reaction, but also complex kinetics and transport phenomena, because the internal reforming reaction and the water-gas shift reaction take place together with reverse diffusion of the ambient gas from the surroundings of the cell. The purpose of this paper is to theoretically explain the experimental results of the anodic concentration profile of gaseous species previously reported in a practical seal-less disk-type cell which used pre-reforming methane with steam as a fuel. A numerical model that takes into account the transport phenomena of the gaseous species and the internal reforming reaction with the water-gas shift reaction together with the assumption of the cell outlet boundary condition was constructed to numerically analyse the gas composition distribution and power generation characteristics. Numerical analyses by the model were conducted for the several cases reported as the experiment. The calculated results in the anode gas concentration profile and in the voltage-current characteristics show good agreement with the experimental data in every case, and then the validity of the simulation model was verified. Therefore, the model is useful for a seal-less disk-type cell which is operated by a fuel including non-reformed methane.

  6. Renewable Electricity Generation via Solar-Powered Methanol Reforming: Hybrid Proton Exchange Membrane Fuel Cell Systems Based on Novel Non-Concentrating, Intermediate-Temperature Solar Collectors

    Real, Daniel J.

    Tremendous research efforts have been conducted studying the capturing and conversion of solar energy. Solar thermal power systems offer a compelling opportunity for renewable energy utilization with high efficiencies and excellent cost-effectiveness. The goal of this work was to design a non-concentrating collector capable of reaching temperatures above 250 °C, use this collector to power methanol steam reforming, and operate a proton exchange membrane (PEM) fuel cell using the generated hydrogen. The study presents the construction and characterization of a non-concentrating, intermediate-temperature, fin-in-tube evacuated solar collector, made of copper and capable of reaching stagnation temperatures of 268.5 °C at 1000 W/m2 irradiance. The collector was used to power methanol steam reforming, including the initial heating and vaporization of liquid reactants and the final heating of the gaseous reactants. A preferential oxidation (PROX) catalyst was used to remove CO from simulated reformate gas, and this product gas was used to operate a PEM fuel cell. The results show 1) that the outlet temperature is not limited by heat transfer from the absorber coating to the heat transfer fluid, but by the amount of solar energy absorbed. This implicates a constant heat flux description of the heat transfer process and allows for the usage of materials with lower thermal conductivity than copper. 2) It is possible to operate a PEM fuel cell from reformate gas if a PROX catalyst is used to remove CO from the gas. 3) The performance of the fuel cell is only slightly decreased (~4%) by CO2 dilution present in the reformate and PROX gas. These results provide a foundation for the first renewable electricity generation via solar-powered methanol reforming through a hybrid PEM fuel cell system based on novel non-concentrating, intermediate-temperature solar collectors.

  7. Integration of stochastic generation in power systems

    Papaefthymiou, G.


    Stochastic Generation is the electrical power production by the use of an uncontrollable prime energy mover, corresponding mainly to renewable energy sources. For the large-scale integration of stochastic generation in power systems, methods are necessary for the modeling of power generation uncerta

  8. Assembly of coupled redox fuel cells using copper as electron acceptors to generate power and its in-situ retrieval

    Zhang, Hui-Min; Xu, Wei; Li, Gang; Liu, Zhan-Meng; Wu, Zu-Cheng; Li, Bo-Geng


    Energy extraction from waste has attracted much interest nowadays. Herein, a coupled redox fuel cell (CRFC) device using heavy metals, such as copper, as an electron acceptor is assembled to testify the recoveries of both electricity and the precious metal without energy consumption. In this study, a NaBH4-Cu(II) CRFC was employed as an example to retrieve copper from a dilute solution with self-electricity production. The properties of the CRFC have been characterized, and the open circuit voltage was 1.65 V with a maximum power density of 7.2 W m-2 at an initial Cu2+ concentration of 1,600 mg L-1 in the catholyte. 99.9% of the 400 mg L-1 copper was harvested after operation for 24 h, and the product formed on the cathode was identified as elemental copper. The CRFC demonstrated that useful chemicals were recovered and the electricity contained in the chemicals was produced in a self-powered retrieval process.

  9. Different electrode configurations to optimize performance of multi-electrode microbial fuel cells for generating power or treating domestic wastewater

    Ahn, Yongtae


    Scaling-up of microbial fuel cells (MFCs) for practical applications requires compact, multiple-electrode designs. Two possible configurations are a separator electrode assembly (SEA) or closely spaced electrodes (SPA) that lack a separator. It is shown here that the optimal configuration depends on whether the goal is power production or rate of wastewater treatment. SEA MFCs produced a 16% higher maximum power density (328 ± 11 mW m-2) than SPA MFCs (282 ± 29 mW m-2), and higher coulombic efficiencies (SEAs, 9-31%; SPAs, 2-23%) with domestic wastewater. However, treatment was accomplished in only 12 h with the SPA MFC, compared to 36 h with the SEA configuration. Ohmic resistance was not a main factor in performance as this component contributed only 4-7% of the total internal resistance. Transport simulations indicated that hindered oxygen diffusion into the SEA reactor was the primary reason for the increased treatment time. However, a reduction in the overall rate of substrate diffusion also may contribute to the long treatment time with the SEA reactor. These results suggest that SEA designs can more effectively capture energy from wastewater, but SPA configurations will be superior in terms of treatment efficiency due to a greatly reduced time needed for treatment. © 2013 Elsevier B.V. All rights reserved.

  10. Silicon quantum dots embedded in amorphous SiC matrix for third-generation solar cells: Microstructure control by RF discharge power

    Cheng, Qijin; Levchenko, Igor; Song, Denyuan; Xu, Shuyan; Ostrikov, Kostya Ken


    A low-frequency (460 kHz), low-pressure, thermally non-equilibrium, high-density inductively coupled plasma (ICP) has been used to synthesize a novel, advanced photovoltaic material suitable for fabrication of third-generation solar cells. Silicon quantum dots (SQDs) embedded in an amorphous silicon carbide matrix were prepared at a very low substrate temperature of approximately 200°C without any hydrogen dilution. The effect of the radio-frequency (RF) power of the plasma discharge on the morphology and structure of the embedded quantum dots was studied. A brief discussion on the possible mechanisms of the quantum dot formation in the ICP is presented. This study is relevant to third-generation photovoltaic solar cells.

  11. Combined heat and power generation with fuel cells in residential buildings in the future energy system; Kraft-Waerme-Kopplung mit Brennstoffzellen in Wohngebaeuden im zukuenftigen Energiesystem

    Jungbluth, C.H.


    Combined heat and power generation (CHP) is regarded as one of the cornerstones of a future sustainable energy system. The application of this approach can be substantially extended by employing fuel cell technologies in small units for supplying heat to residential buildings. This could create an additional market for combined heat and power generation corresponding to approx. 25% of the final energy demand in Germany today. In parallel, the extensive application of distributed fuel cell systems in residential buildings would have substantial effects on energy infrastructures, primary energy demand, the energy mix and greenhouse gas emissions. It is the aim of the present study to quantify these effects via scenario modelling of energy demand and supply for Germany up to the year 2050. Two scenarios, reference and ecological commitment, are set up, and the application and operation of fuel cell plants in the future stock of residential buildings is simulated by a bottom-up approach. A model of the building stock was developed for this purpose, consisting of 213 types of reference buildings, as well as detailed simulation models of the plant operation modes. The aim was, furthermore, to identify economically and ecologically optimised plant designs and operation modes for fuel cells in residential buildings. Under the assumed conditions of the energy economy, economically optimised plant sizes for typical one- or two-family homes are in the range of a generating capacity of a few hundred watts of electrical power. Plant sizes of 2 to 4.7 kW{sub el} as discussed today are only economically feasible in multifamily dwellings. The abolition of the CHP bonus reduces profitability, especially for larger plants operated by contractors. In future, special strategies for power generation and supply can be an economically useful addition for the heat-oriented operation mode of fuel cells. On the basis of the assumed conditions of the energy economy, a technical potential for

  12. Microfluidic fuel cells for energy generation.

    Safdar, M; Jänis, J; Sánchez, S


    Sustainable energy generation is of recent interest due to a growing energy demand across the globe and increasing environmental issues caused by conventional non-renewable means of power generation. In the context of microsystems, portable electronics and lab-on-a-chip based (bio)chemical sensors would essentially require fully integrated, reliable means of power generation. Microfluidic-based fuel cells can offer unique advantages compared to conventional fuel cells such as high surface area-to-volume ratio, ease of integration, cost effectiveness and portability. Here, we summarize recent developments which utilize the potential of microfluidic devices for energy generation. PMID:27367869

  13. Specification for dispersed fuel-cell generator

    Handley, L. M.; Cohen, R.


    A general description and performance definition for a standard 11-mw fuel cell power plant designed for electric utility dispersed-generation applications are provided. Additional features available at the option of the purchaser are also described. The power plant can operate singly or grouped with other power plants to produce larger mutli-megawatt power stations. A 33-mw station is discussed as representative of multiple power plant installations. The power plant specification defines power rating, heat rate, fuels, operating modes, siting characteristics, and available options. A general description included in the attachments covers equipment, typical site arrangement, auxiliary subsystems, maintenance, fuel flexibility, and general fluid and electrical schematics.

  14. Coal gasification integration with solid oxide fuel cell and chemical looping combustion for high-efficiency power generation with inherent CO2 capture

    Highlights: • A novel power system integrating coal gasification with SOFC and chemical looping combustion. • The plant net power efficiency reaches 49.8% with complete CO2 separation. • Energy and exergy analysis of the entire plant is conducted. • Sensitivity analysis shows a nearly constant power output when SOFC temperature and pressure vary. • NiO oxygen carrier shows higher plant efficiency than using Fe2O3 and CuO. - Abstract: Since solid oxide fuel cells (SOFC) produce electricity with high energy conversion efficiency, and chemical looping combustion (CLC) is a process for fuel conversion with inherent CO2 separation, a novel combined cycle integrating coal gasification, solid oxide fuel cell, and chemical looping combustion was configured and analyzed. A thermodynamic analysis based on energy and exergy was performed to investigate the performance of the integrated system and its sensitivity to major operating parameters. The major findings include that (1) the plant net power efficiency reaches 49.8% with ∼100% CO2 capture for SOFC at 900 °C, 15 bar, fuel utilization factor = 0.85, fuel reactor temperature = 900 °C and air reactor temperature = 950 °C, using NiO as the oxygen carrier in the CLC unit. (2) In this parameter neighborhood the fuel utilization factor, the SOFC temperature and SOFC pressure have small effects on the plant net power efficiency because changes in pressure and temperature that increase the power generation by the SOFC tend to decrease the power generation by the gas turbine and steam cycle, and v.v.; an advantage of this system characteristic is that it maintains a nearly constant power output even when the temperature and pressure vary. (3) The largest exergy loss is in the gasification process, followed by those in the CO2 compression and the SOFC. (4) Compared with the CLC Fe2O3 and CuO oxygen carriers, NiO results in higher plant net power efficiency. To the authors’ knowledge, this is the first analysis

  15. Electronic power generators for ultrasonic frequencies

    Ciovica, D.


    The design and construction of an ultrasonic frequency electronic power generator are discussed. The principle design elements of the generator are illustrated. The generator provides an inductive load with an output power of two kilowatts and a variable output frequency in the fifteen to thirty KiloHertz range. The method of conducting the tests and the results obtained with selected materials are analyzed.

  16. Low Power Microrobotics Utilizing Biologically Inspired Energy Generation Project

    National Aeronautics and Space Administration — Description: building a small microrover that employs energy generated by a bacterial source Objective: investigate the usability of a microbial fuel cell to power...

  17. Wind Generators and Market Power

    Misir, Nihat

    Electricity production from wind generators holds significant importance in European Union’s 20% renewable energy target by 2020. In this paper, I show that ownership of wind generators affects market outcomes by using both a Cournot oligopoly model and a real options model. In the Cournot...... oligopoly model, ownership of the wind generators by owners of fossil-fueled (peakload) generators decreases total peakload production and increases the market price. These effects increase with total wind generation and aggregate wind generator ownership. In the real options model, start up and shut down...

  18. AGAPUTE - Advanced gas purification technologies for co-gasification of coal, refinery by-products, biomass & waste, targeted to clean power produced from gas & steam turbine generator sets and fuel cells. FINAL REPORT

    Di Donato, Antonello; Puigjaner Corbella, Lluís; Velo García, Enrique; Nougués, José María; Pérez Fortes, María del Mar; Bojarski, Aarón David


    Informe Final del Projecte ECSC RFC-CR-04006: AGAPUTE - Advanced gas purification technologies for co-gasification of coal, refinery by-products, biomass & waste, targeted to clean power produced from gas & steam turbine generator sets and fuel cells

  19. Biofuel Cells – Alternative Power Sources

    Energy generation from renewable sources and effective waste treatment are two key challenges for the sustainable development. Microbiological (or Bio-) Fuel Cells provide an elegant solution by linking both tasks. Biofuel cells, which can directly generate electricity from biodegradable substances, have rapidly gained increasing research attention. Widely available fuel sources and moderate operational conditions make them promising in renewable energy generation, wastewater treatment, power sources for remote devices, etc. This paper reviews the use of microorganisms as biocatalysts in microbiological fuel cells. The principle of biofuel cells and their construction elements are discussed. Keywords: alternative power sources, biofuel cells, biocatalysts

  20. Distributed Generation and Resilience in Power Grids

    Scala, Antonio; Chessa, Alessandro; Caldarelli, Guido; Damiano, Alfonso


    We study the effects of the allocation of distributed generation on the resilience of power grids. We find that an unconstrained allocation and growth of the distributed generation can drive a power grid beyond its design parameters. In order to overcome such a problem, we propose a topological algorithm derived from the field of Complex Networks to allocate distributed generation sources in an existing power grid.

  1. An integrated power generation system combining solid oxide fuel cell and oxy-fuel combustion for high performance and CO2 capture

    An integrated power generation system combining solid oxide fuel cell (SOFC) and oxy-fuel combustion technology is proposed. The system is revised from a pressurized SOFC-gas turbine hybrid system to capture CO2 almost completely while maintaining high efficiency. The system consists of SOFC, gas turbine, oxy-combustion bottoming cycle, and CO2 capture and compression process. An ion transport membrane (ITM) is used to separate oxygen from the cathode exit air. The fuel cell operates at an elevated pressure to facilitate the use of the ITM, which requires high pressure and temperature. The remaining fuel at the SOFC anode exit is completely burned with oxygen at the oxy-combustor. Almost all of the CO2 generated during the reforming process of the SOFC and at the oxy-fuel combustor is extracted from the condenser of the oxy-combustion cycle. The oxygen-depleted high pressure air from the SOFC cathode expands at the gas turbine. Therefore, the expander of the oxy-combustion cycle and the gas turbine provides additional power output. The two major design variables (steam expander inlet temperature and condenser pressure) of the oxy-fuel combustion system are determined through parametric analysis. There exists an optimal condenser pressure (below atmospheric pressure) in terms of global energy efficiency considering both the system power output and CO2 compression power consumption. It was shown that the integrated system can be designed to have almost equivalent system efficiency as the simple SOFC-gas turbine hybrid system. With the voltage of 0.752 V at the SOFC operating at 900 oC and 8 bar, system efficiency over 69.2% is predicted. Efficiency penalty due to the CO2 capture and compression up to 150 bar is around 6.1%.

  2. Electric power generation using photovoltaic solar cells for low income rural population; Geracao de energia eletrica com celula solar fotovoltaica para populacao rural de baixa renda

    Gastaldi, Andre Fava; Souza, Teofilo Miguel de; Mesquita, Rafael Pimenta [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Guaratingueta, SP (Brazil). Centro de Energias Renovaveis], e-mail:


    With the growing electric energy use demand and almost not expansion of the energy mesh (basically composed by hydroelectric plants) existing in the country, several others methods of alternative energy generation may be necessary. Beyond that, the usually employed energy is becoming much more costly, rarer and politically more impracticable like burn fuels as oil and coal. The use of renewable approaches of energy, that are 'infinite' energies (as the wind and the light of the sun, for example), can become an excellent alternative. In this new energy group, the solar energy transformed by the use of photo voltage cells is becoming very important. The 'clear' solar radiation tends to be a more intelligent and practical option, and the future technology of energy storage will be able to solve the problem of the regions that have less sunny days. Its main advantages on the other alternative sources of energy are the trustworthiness and the previsibility. Its biggest disadvantage consists on the fact that technical limitations can not allow a solar energy generator to distribute electricity for a city. It is interesting to notice that with the development of projects as this in alternative energy, isolated areas that does not access electricity distribution network (as some far regions), it has become the most viable option of generation of electric energy. Another point is that even with the distribution network it has to be checked if it is possible to use this electricity consulting the company credential that work at those localities of consumption. Moreover, many regions of the country already installed the solar energy system for water heating, confirming that, the existing structure allows the installation of a a solar cells generation energy system without many problems. In this project, we introduce a method for electric energy generation by solar cells for rural population of low gains. This option uses low cost materials but with a good

  3. Decentralized power generation from biogas

    Areva Bioenergies proposes ready-to-use biogas production and valorization units that use industrial effluents (liquid effluents, spent water, solid wastes). Biogas valorization is performed through cogeneration plants with an output power of 500 kW to 10 MW. This brochure presents Areva's global offer in methanation projects (support, engineering, optimization). Areva Bioenergies counts 20 dual-purpose power plants in operation or under construction in the world which represent an installed power of 220 MW

  4. Directly driven generators for wind power applications

    Lampola, P. [Helsinki Univ. of Technology, Espoo (Finland). Lab. of Electromechanics


    The article deals with an analysis of directly driven, low-speed wind generators. The generators studied were a permanent-magnet synchronous machine and an asynchronous machine. The machines were compared with a typical generator of a wind power plant. The electromagnetic optimization of the machines was done by the finite element method. The rated power of the generators was 500 kW and the rotational speed was 40 rpm. (author)

  5. Development of Micro-sized Microbial Fuel Cells as Ultra-Low Power Generators Using Nano-engineered Materials and Sustainable Designs

    Mink, Justine E.


    Many of the most pressing global challenges today and in the future center around the scarcity of sustainable energy and water sources. The innovative microbial fuel cell (MFC) technology addresses both as it utilizes bacteria to convert wastewaters into electricity. Advancing this technology requires a better understanding of the optimal materials, designs and conditions involved. The micro-sized MFC was recently developed to serve this need by providing a rapid testing device requiring only a fraction of the materials. Further, development of micro-liter scale MFCs has expanded into potential applications such as remote and self-sustained power sources as well as on-chip energy generators. By using microfabrication, the fabrication and assembly of microsized MFCs is potentially inexpensive and mass produced. The objective of the work within this dissertation was to explore and optimize the micro-sized MFC to maximize power and current generation towards the goal of a usable and application-oriented device. Micro-sized MFCs were examined and developed using four parameters/themes considered most important in producing a high power generating, yet usable device: Anode- The use of nano-engineered carbon nanomaterials, carbon nanotubes and graphene, as anode as well as testing semiconductor industry standard anode contact area materials for enhanced current production. 5 Cathode- The introduction of a membrane-less air cathode to eliminate the need for continuous chemical refills and making the entire device mobile. Reactor design- The testing of four different reactor designs (1-75 μLs) with various features intended to increase sustainability, cost-effectiveness, and usability of the microsized MFC. Fuels- The utilization of real-world fuels, such as industrial wastewaters and saliva, to power micro-sized MFCs. The micro-sized MFC can be tailored to fit a variety of applications by varying these parameters. The device with the highest power production here was

  6. Conscience of Japanese on nuclear power generation

    There are considerably many investigations and researches on the attitude of general public to nuclear power generation, but those which analyzed the contents of attitude or the research which got into the problem of what method is desirable to obtain the understanding of nuclear power generation for power generation side is rarely found. Therefore, the research on where is its cause was begun. As the result, since the attitude to nuclear power generation is related to the attitudes to many things that surround nuclear power generation in addition to that directly to nuclear power generation, it is necessary to elucidate the problem synthetically. The social investigation was carried out for the public of from 18 to 79 years old who live in the supply area of Kansai Electric Power Co., Inc. The data were obtained from those selected by probabilistic sampling, 1000 in urban area (rate of recovery 76%) and 440 in country area (rate of recovery 77%). The way of thinking on making questionnaire is shown. The investigation and the analysis of the obtained data were carried out. What do you recollect as a dangerous matter, the attitude to nuclear power generation, the structure of the conscience to nuclear power generation and its significance, the type classification of people and its features are reported and discussed. (K.I.)

  7. Radio-frequency power generation

    Carter, Richard G.


    This paper reviews the main types of radio-frequency power amplifiers which are, or may be, used for high-power hadron accelerators. It covers tetrodes, inductive output tubes, klystrons and magnetrons with power outputs greater than 10 kW continuous wave or 100 kW pulsed at frequencies from 50 MHz to 30 GHz. Factors affecting the satisfactory operation of amplifiers include cooling, matching and protection circuits are discussed. The paper concludes with a summary of the state of the art for...

  8. Forecasting Electric Power Generation of Photovoltaic Power System for Energy Network

    Kudo, Mitsuru; Takeuchi, Akira; Nozaki, Yousuke; Endo, Hisahito; Sumita, Jiro

    Recently, there has been an increase in concern about the global environment. Interest is growing in developing an energy network by which new energy systems such as photovoltaic and fuel cells generate power locally and electric power and heat are controlled with a communications network. We developed the power generation forecast method for photovoltaic power systems in an energy network. The method makes use of weather information and regression analysis. We carried out forecasting power output of the photovoltaic power system installed in Expo 2005, Aichi Japan. As a result of comparing measurements with a prediction values, the average prediction error per day was about 26% of the measured power.

  9. Power generation using photovoltaic induction in an isolated power network

    Owing to increased emphasis on renewable resources, the development of suitable isolated power generators driven by energy sources, the development of suitable isolated power generators driven by energy sources such as photovoltaic, wind, small hydroelectric, biogas and etc. has recently assumed greater significance. A single phase capacitor self excited induction generator has emerged as a suitable candidate of isolated power sources. This paper presents performance analysis of a single phase self-excited induction generator driven by photovoltaic (P V) system for low power isolated stand-alone applications. A single phase induction machine can work as a self-excited induction generator when its rotor is driven at suitable speed by an photovoltaic powered do motor. Its excitation is provided by connecting a single phase capacitor bank at a stator terminals. Either to augment grid power or to get uninterrupted power during grid failure stand-alone low capacity ac generators are used. These are driven by photovoltaic, wind power or I C engines using kerosene, diesel, petrol or biogas as fuel. Self-excitation with capacitors at the stator terminals of the stator terminals of the induction machines is well demonstrated experimentally on a P V powered dc motor-induction machine set. The parameters and the excitation requirements of the induction machine run in self-excited induction generator mode are determined. The effects of variations in prime mover speed,terminal capacitance and load power factor on the machine terminal voltage are studied

  10. Infrared power cells for satellite power conversion

    Summers, Christopher J.


    An analytical investigation is performed to assess the feasibility of long-wavelength power converters for the direct conversion of IR radiation onto electrical power. Because theses devices need to operate between 5 and 30 um the only material system possible for this application is the HgCdTe system which is currently being developed for IR detectors. Thus solar cell and IR detector theories and technologies are combined. The following subject areas are covered: electronic and optical properties of HgCdTe alloys; optimum device geometry; junction theory; model calculation for homojunction power cell efficiency; and calculation for HgCdTe power cell and power beaming.

  11. Miniature Gas-Turbine Power Generator

    Wiberg, Dean; Vargo, Stephen; White, Victor; Shcheglov, Kirill


    A proposed microelectromechanical system (MEMS) containing a closed- Brayton-cycle turbine would serve as a prototype of electric-power generators for special applications in which high energy densities are required and in which, heretofore, batteries have been used. The system would have a volume of about 6 cm3 and would operate with a thermal efficiency >30 percent, generating up to 50 W of electrical power. The energy density of the proposed system would be about 10 times that of the best battery-based systems now available, and, as such, would be comparable to that of a fuel cell. The working gas for the turbine would be Xe containing small quantities of CO2, O2, and H2O as gaseous lubricants. The gas would be contained in an enclosed circulation system, within which the pressure would typically range between 5 and 50 atm (between 0.5 and 5 MPa). The heat for the Brayton cycle could be supplied by any of a number of sources, including a solar concentrator or a combustor burning a hydrocarbon or other fuel. The system would include novel heat-transfer and heat-management components. The turbine would be connected to an electric power generator/starter motor. The system would include a main rotor shaft with gas bearings; the bearing surfaces would be made of a ceramic material coated with nanocrystalline diamond. The shaft could withstand speed of 400,000 rpm or perhaps more, with bearing-wear rates less than 10(exp -)4 those of silicon bearings and 0.05 to 0.1 those of SiC bearings, and with a coefficient of friction about 0.1 that of Si or SiC bearings. The components of the system would be fabricated by a combination of (1) three-dimensional xray lithography and (2) highly precise injection molding of diamond-compatible metals and ceramic materials. The materials and fabrication techniques would be suitable for mass production. The disadvantages of the proposed system are that unlike a battery-based system, it could generate a perceptible amount of sound, and

  12. Powerful nanosecond pulse train generator

    A generator permitting to shape on the load pulsed with the repetition frequency of 103-106 Hz and more is described. The amplitude of shaped voltage pulses is up to 150 kV at pulse duration equal to 50 ns. The generator comprises connected in-series with the load two shaping and two transmission lines realized on the base of the KVI-300 low-ohmic cable. The shaping lines are supplied from two independently connected pulse voltage generators for obtaining time interval between pulses > 10-6 s; they may be also supplied from one generator for obtaining time interval -6 s. At the expense of reducing losses in the discharge circuit the amplitude of the second pulse grows with increase of time interval between pulses up to 300 ns, further on the curve flat-topping exists. The described generator is used in high-current accelerators, in which the primary negative pulse results in generation of explosive-emission plasma, and the second positive pulse provides ion beam shaping including ions of heavy metal used for production of a potential electrode. The generator multipulse mode is used for successive ion acceleration in the transport system

  13. On Maximal Power Point of Photovoltaic Power Generation System

    Setiawan, Eko; Hodaka, Ichijo


    Numerous studies have been developed to get the maximum power of photovoltaic (PV). Most of the studies assume that the maximum power will be reached when the PV works at the maximum power point (MPP). Since the real target is maximizing power at the load-side, that assumption should be clarified. This paper presents an analysis of photovoltaic power generation system. Some numerical value is applied to realize the value. Based on the analysis, difference value of photovoltaic MPP and load MP...

  14. High power density carbonate fuel cell

    Yuh, C.; Johnsen, R.; Doyon, J.; Allen, J. [Energy Research Corp., Danbury, CT (United States)


    Carbonate fuel cell is a highly efficient and environmentally clean source of power generation. Many organizations worldwide are actively pursuing the development of the technology. Field demonstration of multi-MW size power plant has been initiated in 1996, a step toward commercialization before the turn of the century, Energy Research Corporation (ERC) is planning to introduce a 2.85MW commercial fuel cell power plant with an efficiency of 58%, which is quite attractive for distributed power generation. However, to further expand competitive edge over alternative systems and to achieve wider market penetration, ERC is exploring advanced carbonate fuel cells having significantly higher power densities. A more compact power plant would also stimulate interest in new markets such as ships and submarines where space limitations exist. The activities focused on reducing cell polarization and internal resistance as well as on advanced thin cell components.

  15. A large capacity turbine generator for nuclear power generation

    In future large capacity nuclear power plant, capacity of a generator to be applied will be 1800 MVA of the largest class in the world. In response to this, the Mitsubishi Electric Co., Ltd. began to carry out element technology verification of a four-pole large capacity turbine generator mainly using upgrading technique of large capacity, since 1994 fiscal year. And, aiming at reliability verification of the 1800 MVA class generator, a model generator with same cross-section as that of an actual one was manufactured, to carry out some verifications on its electrified tests, and so on. Every performance evaluation result of tests on the model generator were good, and high reliability to design and manufacturing technique of the 1800 MVA class generator could be verified. In future, on the base of these technologies, further upgrading of reliability on the large capacity turbine generator for nuclear power generation is intended to be carried out. (G.K.)

  16. Generate light with wind power

    Iqbal, Fowad


    The report explain the steps taken to improve a product (SOLVINDEN), which uses sun and wind energy to generate light and is used for outdoor decoration. The research involves improvements in both designas well function. As the form follows function in the product functionality of the form is very important in selection of the form. Some of important topics which are considered are different way of using wind to charge batteries, blades profiles and shape, way of optimizing generator, ratio o...

  17. Probabilistic Evaluation of Wind Power Generation

    The power supplied by wind turbine generators (WTG) is widely random following the stochastic nature of weather conditions. For planning and decision making purposes, understanding and evaluation of the behaviour and distribution of WTG's output power are crucial. Monte Carlo simulation enables the realization of artificial futures by generating a huge number of sample paths of outcomes to perform this analysis. The paper presents an algorithm developed for a random wind speed generator governed by the probability density function of Weibull distribution and evaluates the WTG's output by using the power curve of wind turbines. The method may facilitate assessment of suitable turbine site as well as generator selection and sizing.

  18. Cycloidal tidal power generation - Phase 1



    This report summarises the findings of a project investigating the economic and technical viability of a cycloidal tidal stream generator and developing a performance prediction model to assess the applicability of cycloidal turbines to power generation. The concept of cycloidal power generation is described along with the use of the model to examine the performance of six designs in the tidal flow off the west coast of Scotland. Details are given of the estimated power generated and cost reductions using optimised designs. Areas to be examined for design optimisation are listed.

  19. Probabilistic Evaluation of Wind Power Generation

    Muhamad Razali, N. M.; Misbah, Muizzuddin


    The power supplied by wind turbine generators (WTG) is widely random following the stochastic nature of weather conditions. For planning and decision making purposes, understanding and evaluation of the behaviour and distribution of WTG's output power are crucial. Monte Carlo simulation enables the realization of artificial futures by generating a huge number of sample paths of outcomes to perform this analysis. The paper presents an algorithm developed for a random wind speed generator governed by the probability density function of Weibull distribution and evaluates the WTG's output by using the power curve of wind turbines. The method may facilitate assessment of suitable turbine site as well as generator selection and sizing.

  20. Solar energy thermally powered electrical generating system

    Owens, William R. (Inventor)


    A thermally powered electrical generating system for use in a space vehicle is disclosed. The rate of storage in a thermal energy storage medium is controlled by varying the rate of generation and dissipation of electrical energy in a thermally powered electrical generating system which is powered from heat stored in the thermal energy storage medium without exceeding a maximum quantity of heat. A control system (10) varies the rate at which electrical energy is generated by the electrical generating system and the rate at which electrical energy is consumed by a variable parasitic electrical load to cause storage of an amount of thermal energy in the thermal energy storage system at the end of a period of insolation which is sufficient to satisfy the scheduled demand for electrical power to be generated during the next period of eclipse. The control system is based upon Kalman filter theory.

  1. Microwave power engineering generation, transmission, rectification

    Okress, Ernest C


    Microwave Power Engineering, Volume 1: Generation, Transmission, Rectification considers the components, systems, and applications and the prevailing limitations of the microwave power technology. This book contains four chapters and begins with an introduction to the basic concept and developments of microwave power technology. The second chapter deals with the development of the main classes of high-power microwave and optical frequency power generators, such as magnetrons, crossed-field amplifiers, klystrons, beam plasma amplifiers, crossed-field noise sources, triodes, lasers. The third

  2. Electric power generation. Thermal power generating systems. 2. rev. and enl. ed.

    This is a manuscript for a lecture contents: 1. Steam power and fundamentals of the steam power process, 2. conventional, nuclear and other steam generation processes, 3. cooling systems for steam power plants, 4. gas turbine power plants and combined-cycle power plants, 5. cogeneration, 6. development of thermal power plants and environmental effects. (orig.)

  3. Generator technology for HTGR power plants

    Approximately 15% of the worlds installed capacity in electric energy production is from generators developed and manufactured by GEC Alsthom. GEC Alsthom is now working on the application of generators for HTGR power conversion systems. The main generator characteristics induced by the different HTGR power conversion technology include helium immersion, high helium pressure, brushless excitation system, magnetic bearings, vertical lineshaft, high reliability and long periods between maintenance. (author)

  4. Vietnam Power Sector : Generation Options

    World Bank


    This report discusses the energy sector in Vietnam. The central task for the energy sector is to meet demands for electricity in sufficient quantity and of an acceptable quality, in as commercially and financially efficient a way as possible. Several issues arise if this task is to be accomplished in the short and medium term. They are: optimizing power investments; financing the investmen...

  5. Performance Analysis and Optimum Operation Planning of Distributed Energy System Based on Micro Gas Turbine-Solid Oxide Fuel Cell Hybrid Power Generation

    Morita, Aina; Kimijima, Shinji

    In this paper, the economical and energy saving advantages of the distributed energy system, which consists of a micro gas turbine-solid oxide fuel cell hybrid power generation system, waste heat recovery devices and air-conditioning equipments, are investigated. Firstly, the thermodynamical performance evaluation of the hybrid system with the heat recovery devices is discussed to estimate the energy conversion efficiency of the whole system. Secondly, by using 1inear programming technique, the optimum operation planning of the cogeneration plant based on the hybrid system is discussed to predict the reduction of the primary fuel consumption and utility cost. Throughout detailed investigation, it is found that the energy conversion efficiency, which includes the waste heat utilization, reaches over 80% (LHV). In addition, the optimum operation of the hybrid system, of which power generation capacity is appropriate for the energy demand, achieve the highly effective energy saving against the traditional energy supply scheme, that is, the fuel reduction reaches around 40% to the conventional value.

  6. Economic feasibility analysis of distributed electric power generation based upon the natural gas-fired fuel cell


    The final report provides a summary of results of the Cost of Ownership Model and the circumstances under which a distributed fuel cell is economically viable. The analysis is based on a series of micro computer models estimates of the capital and operations cost of a fuel cell central utility plant configuration. Using a survey of thermal and electrical demand profiles, the study defines a series of energy user classes. The energy user class demand requirements are entered into the central utility plant model to define the required size the fuel cell capacity and all supporting equipment. The central plant model includes provisions that enables the analyst to select optional plant features that are most appropriate to a fuel cell application, and that are cost effective. The model permits the choice of system features that would be suitable for a large condominium complex or a residential institution such as a hotel, boarding school or prison. Other applications are also practical; however, such applications have a higher relative demand for thermal energy, a characteristic that is well-suited to a fuel cell application with its free source of hot water or steam. The analysis combines the capital and operation from the preceding models into a Cost of Ownership Model to compute the plant capital and operating costs as a function of capacity and principal features and compares these estimates to the estimated operating cost of the same central plant configuration without a fuel cell.

  7. Capacity value evaluation of photovoltaic power generation

    The paper presents an example of capacity value (kW-value) evaluation of photovoltaic generation from power companies generation planning point of view. The method actually applied to evaluate the supplying capability of conventional generation plants is briefly described. 21 figs, 1 tab

  8. Ergonomics and nuclear power generation

    The design and construction of nuclear power plants are executed to rigorous standards of safety and reliability. Similarly the human interface within the nuclear power plant must meet very high standards, and these must be demonstrated to be maintained and assured through time. The control room, as the operating nerve-centre of the plant, carries a large part of this responsibility. It is the work space dimension within which the operator-instrumentation interface must function as efficiently as possible. This paper provides an overview of how ergonomics has been used as a major tool in reshaping the man-machine interface within the control room in the interest of safety and reliability. Topics covered in the paper include workspace design, control panel layout, demarcation and labelling, switch and meter types, and annunciated and unannunciated alarms

  9. The generation of sex cells

    Deglincerti, Alessia; Brivanlou, Ali H.


    Primordial germ cells (PGCs) are the earliest population of germ cells established during embryonic development and constitute the beginning of the totipotent state. A recent study provides a new protocol for the efficient generation of PGC-like cells from human embryonic stem cells, providing an in vitro platform to study human PGC differentiation and specification.

  10. Converters for Distributed Power Generation Systems

    Blaabjerg, Frede; Yang, Yongheng


    Power electronics technology has become the enabling technology for the integration of distributed power generation systems (DPGS) such as offshore wind turbine power systems and commercial photovoltaic power plants. Depending on the applications, a vast array of DPGS-based power converter...... topologies has been developed and more are coming into the market in order to achieve an efficient and reliable power conversion from the renewables. In addition, stringent demands from both the distribution system operators and the consumers have been imposed on the renewable-based DPGS. This article...

  11. Power: towards a third generation definition

    J. Zaaiman


    Full Text Available Power is a well-established concept in the social sciences especially in the political sciences. Although it is widely used in scientific discourse, different definitions and perspectives prevail with regard to it. This article aims to explore the possibilities of taking the debate further towards a third generation definition of social power. Although first generation definitions (associated with Weber and Dahl and second generation definitions (associated with inter alia Giddens and Morriss are still widely used in the academic field, they do not reflect the depth of the continuous debate on the concept of power. Viewpoints, especially with regard to agency and freedom, are not reflected in current definitions. To this can also be added the important dynamic relationship between power and change. This article summarises the important aspects of power debates relevant for defining power and discusses possible ways in which this can be accommodated in a definition of power. The current debate on the relationship between power and change is also reinterpreted with regard to defining social power. The article concludes by proposing necessary aspects of a third generation definition of power and suggests such a definition.

  12. Microscale combustion and power generation

    Cadou, Christopher


    Recent advances in microfabrication technologies have enabled the development of entirely new classes of small-scale devices with applications in fields ranging from biomedicine, to wireless communication and computing, to reconnaissance, and to augmentation of human function. In many cases, however, what these devices can actually accomplish is limited by the low energy density of their energy storage and conversion systems. This breakthrough book brings together in one place the information necessary to develop the high energy density combustion-based power sources that will enable many of

  13. Electric power generation in large-scale power plants

    Future electric power consumption will be depending on the economic development of the Federal Republic of Germany. Thermal power plants are fueled with non-renewable energy sources, i.e. coal, petroleum, natural gas or nuclear power. It is therefore important to assess the global coverage of these energy sources and to take stock of the reserves of the Federal Republic of Germany. If the waste heat left from electric power generation was made use of in dual-purpose power plants total energy consumption could be considerably reduced. Large-scale power plants do have to face and cope with the lack of distribution networks to supply the consumer. (DG)

  14. Liberation of electric power and nuclear power generation

    In Japan, as the Rule on Electric Business was revised after an interval of 35 years in 1995, and a competitive bid on new electric source was adopted after 1996 fiscal year, investigation on further competition introduction to electric power market was begun by establishment of the Basic Group of the Electric Business Council in 1997. By a report proposed on January, 1999 by the Group, the Rule was revised again on March, 1999 to start a partial liberation or retail of the electric power from March, 2000. From a viewpoint of energy security and for solution of global environmental problem in Japan it has been decided to positively promote nuclear power in future. Therefore, it is necessary to investigate how the competition introduction affects to development of nuclear power generation and what is a market liberation model capable of harmonizing with the development on liberation of electric power market. Here was elucidated on effect of the introduction on previous and future nuclear power generation, after introducing new aspects of nuclear power problems and investigating characteristic points and investment risks specific to the nuclear power generation. And, by investigating some possibilities to development of nuclear power generation under liberation models of each market, an implication was shown on how to be future liberation on electric power market in Japan. (G.K.)

  15. Exoelectrogenic bacteria that power microbial fuel cells

    Logan, Bruce E.


    There has been an increase in recent years in the number of reports of microorganisms that can generate electrical current in microbial fuel cells. Although many new strains have been identified, few strains individually produce power densities as high as strains from mixed communities. Enriched anodic biofilms have generated power densities as high as 6.9 W per m2 (projected anode area), and therefore are approaching theoretical limits. To understand bacterial versatility in mechanisms used for current generation, this Progress article explores the underlying reasons for exocellular electron transfer, including cellular respiration and possible cell-cell communication.

  16. Power Smoothing and MPPT for Grid-connected Wind Power Generation with Doubly Fed Induction Generator

    Kai, Takaaki; Tanaka, Yuji; Kaneda, Hirotoshi; Kobayashi, Daichi; Tanaka, Akio

    Recently, doubly fed induction generator (DFIG) and synchronous generator are mostly applied for wind power generation, and variable speed control and power factor control are executed for high efficiently for wind energy capture and high quality for power system voltage. In variable speed control, a wind speed or a generator speed is used for maximum power point tracking. However, performances of a wind generation power fluctuation due to wind speed variation have not yet investigated for those controls. The authors discuss power smoothing by those controls for the DFIG inter-connected to 6.6kV distribution line. The performances are verified using power system simulation software PSCAD/EMTDC for actual wind speed data and are examined from an approximate equation of wind generation power fluctuation for wind speed variation.

  17. Development of micro power generators - A review

    The demand for energy sources that are compact, lightweight and powerful has significantly increased in recent years. Traditional chemical batteries which are highly developed are unable to meet the demand for high energy intensity. This gap is expected to widen in the future as electronic devices need more power to support enhanced functionalities. Hydrocarbon fuels have energy densities much greater than the best batteries. Therefore, taking advantage of the high energy density of chemical fuels to generate power becomes an attractive technological alternative to batteries. To address the growing demand for smaller scale and higher energy density power sources, various combustion-based micro power generators are being developed around the world. This review paper provides an update on recent progresses and developments in micro-scale combustion and micro power generators. The paper, broadly divided into four main sections, begins with a review of various methods to enhance and stabilize the combustion at micro-scale, subsequently improving the efficiency. This is followed by a description of various micro-thermophotovoltaic power generators. The third section focuses on MEMS based solid propellant micro-propulsion system. Lastly, a brief review is made to other micro power generators.

  18. Sustainable Power Generation by Plasma Physics

    Anyaegbunam F. N. C. (Ph.D.


    Full Text Available One of the greatest challenges of developing countries today is electric power generation. The demand for Electric power is far above generation and distribution capacities. For instance, only about 4000MW of electricity is available for nearly 170 million people in Nigeria today. On the other hand, the cities are littered with municipal solid wastes in open dumps which are dangerous to health and environment. Sustainable and successful waste management should be safe, effective, environmentally friendly and economically viable.Application of plasma Physics in waste to energy can be one of the novel ways of sustainable power generation. In plasma gasifying cupola, the organic waste materials are gasified to generate a syngas and steam which can be used to generate electricity by integrated gasification combine circle. The inorganic part of the waste is vitrified to a benign residue used for construction. This paper describes the physics and technology involved, reviews the power situation in Nigeria and the benefits of implementation of this technology in waste to electric power generation. This might be an environmentally Safe and sustainable economic solution for waste management and alternative clean power generation

  19. Power and the future generation

    In this keynote address, the author, who was acting president of AECL at the time of the conference, emphasizes the importance of nuclear energy to Canada, and its future importance to the developing countries. In 1992, nuclear energy supplied 15% of Canada's electricity, employed 30,000 people in Canada, created at least 10,000 jobs in other sectors, generated federal tax revenues of C$700 million, and by supplanting coal and gas imports saved about C$1 billion. Export sales prospects in China, Korea, Turkey, the Philippines, Indonesia and Thailand are indicated. AECL is presently undergoing reorganization for greater efficiency. A public opinion poll indicated about 70% Canadian public support for nuclear energy

  20. The third generation of nuclear power development

    Developing nations use the nuclear plant option to satisfy important overall national development objectives, in addition to providing economical electric power. The relative importance of these two objectives changes as the nuclear program develops and the interim milestones are reached. This paper describes the three typical stages of nuclear power development programs. The first and the second generations are development phases with the third generation reaching self sufficiency. Examples are presented of European and Far East countries or regions which have reached of are about to step into the third generation phase of development. The paper concludes that to achieve the objective of a nuclear power self sufficiency, other than merely filling the need of economical electric power, a careful technology transfer plan must be followed which sets realistic and achievable goals and establishes the country as a reliable and technically competent member of the nuclear power industry. (author)

  1. Sustainable Power Generation by Plasma Physics

    Anyaegbunam F. N. C. (Ph.D.)


    One of the greatest challenges of developing countries today is electric power generation. The demand for Electric power is far above generation and distribution capacities. For instance, only about 4000MW of electricity is available for nearly 170 million people in Nigeria today. On the other hand, the cities are littered with municipal solid wastes in open dumps which are dangerous to health and environment. Sustainable and successful waste management should be safe, effective, environmen...

  2. Bike-powered electricity generator



    Full Text Available Finding new energy sources is an important challenge of our times. A lot of research focuses on identifying such sources that can also be exploited with relatively simple and efficient systems. These sources can be either new materials that can be used to generate energy, or solutions to scavenge already existing forms of energy. Part of the latter class of solutions, the system presented in this paper converts the energy consumed by many people in gyms (or even at home, during exercise into electric energy. This energy exists anyway, because people want to be healthier or to look better. Currently, this significant (in our opinion amount of energy is actually wasted and transformed into heat. Instead, in this study, a prototype scavenging system (dedicated to fitness/stationary bikes to collect and (reuse this energy is presented. Specifically, we depict the design of a low-budget system that uses existing, discrete components and is able to scavenge some of the energy spent by the biker. The experimental results show that the system is functional, but its efficiency is limited by (mechanical losses before the collection.

  3. Bipolar high voltage pulse power generator

    Lukeš, Petr; Člupek, Martin; Babický, Václav; Šunka, Pavel

    Monterey, 2005, s. 44. [IEEE International Pulsed Power Conference/15th./. Portola Plaza Hotel, Monterey, CA, USA (US), 13.06.2005-17.06.2005] R&D Projects: GA AV ČR KSK2043105 Keywords : bipolar * pulse power generator * corona discharge Subject RIV: BL - Plasma and Gas Discharge Physics

  4. Reactive power management of power networks with wind generation

    Amaris, Hortensia; Ortega, Carlos Alvarez


    As the energy sector shifts and changes to focus on renewable technologies, the optimization of wind power becomes a key practical issue. Reactive Power Management of Power Networks with Wind Generation brings into focus the development and application of advanced optimization techniques to the study, characterization, and assessment of voltage stability in power systems. Recent advances on reactive power management are reviewed with particular emphasis on the analysis and control of wind energy conversion systems and FACTS devices. Following an introduction, distinct chapters cover the 5 key

  5. Nuclear power generation through a diagram

    It composed of a lot of charts about energy use and civilization, energy for food, clothing and shelter, tendency of consumption of world energy, distribution chart energy resources of the world and dependence of energy import in major countries, increased demand of electric power, influence of outage, plan for development of power long term in Korea, nuclear power generation of the world, nuclear reactor use, trend electric charges in Korea, radiation and management of radioactive waste, all kinds of disasters and public opinions.

  6. Space photovoltaic power generation. Uchu taiyo hatsuden ni tsuite

    Kudo, I. (Electrotechnical Laboratory, Tsukuba (Japan))


    Introduction is made of space photovoltaic power generation which is the ultimate clean energy source. This is a system to obtain electric energy from the solar cells placed on a geostatic orbit and transmit the power onto the earth by microwave. The US formulates a plan of placing 60[times]5GW power generation satellites to obtain 300GW power on the earth in 2000. As for the scale of space structure, the array of solar cells is dimensionally 10km[times]5km and the power transmitting antenna is 1km in diameter. The electric energy is amplified to microwave and power-transmitted by wireless onto the earth. The ground rectenna which receives it is dimensionally 10km[times]13km. The biggest difficulty consists in transportation of construction materials onto the orbit. In Japan, activity comprises three matters, which are research committee organized three years ago by the Agency of Industrial Science and technology, 10MW class model conceptually designed by the Institute of Space and Astronautical Science, and experiment conducted by Kyoto University on the power transmission by wireless. Pertaining to the research on the space power generation, the following two points are judged still unclarified: Reason for which the electric power companies did not apply the power transmission by wireless regarded as high in transmission efficiency. Influence of the microwave on the ionosphere and biosystem. 7 refs., 4 figs.

  7. Thinking small: Onsite power generation may soon be big

    Utilities are retheinking the way they do business. Eventually, smaller and cleaner generation units located near major load centers could begin to supplement power from central plants. The technologies necessary to this transition are emerging in the form of open-quotes distributed generation.close quotes These technologies typically produce power on a relatively small scale (less than 50 MW per unit) and can be sited in congested urban areas as well as near remote customers. This allows utilities to meet new demand for electricity without building central generating stations and without substantially expanding or upgrading the power delivery system-in other words, at lower cost. Some distributed-generation technologies, such as fuel cells and solar energy harnessed by photovoltaic (PV) cells, are just beginning to carve out niches in th power market. Others, such as engine generator sets and battery storage, have evolved into robust, high-technology systems. In the case of fuel cells and engine-driven systems, natural gas is emerging as an environmentally friendly fuel that should remain available for decades at competitive prices. As gas-fueled distributed power is deployed, utility infrastructures for delivering gas and electricity to customers could become more integrated, allowing planners to smooth load profiles for energy services and creating greater synergies between the two. As distributed-generation technologies become more practical and cost-effective, utilities may find that change can be a path toward least-cost service and sustainable profitability

  8. Nuclear power generation incorporating modern power system practice

    Myerscough, PB


    Nuclear power generation has undergone major expansion and developments in recent years; this third edition contains much revised material in presenting the state-of-the-art of nuclear power station designs currently in operation throughout the world. The volume covers nuclear physics and basic technology, nuclear station design, nuclear station operation, and nuclear safety. Each chapter is independent but with the necessary technical overlap to provide a complete work on the safe and economic design and operation of nuclear power stations.

  9. Fuel cycles for electric power generation

    An illustrative data base is presented of material quantities and environmental effluents in the fuel cycles for alternative technologies of thermally generated power. The entire fuel cycle for each of ten alternative technologies is outlined for a representative power plant generating 1000 Mw of electrical power. The required utilization of material resources and the fuel cycle material quantities are indicated on a flow sheet for each technology. The technologies considered include: light-water nuclear reactors, coal, residual fuel oil, natural gas, geothermal steam, breeder fission reactors, solar energy, and thermonuclear fusion

  10. Draft, development and optimization of a fuel cell system for residential power generation with steam reformer; Entwurf, Aufbau und Optimierung eines PEM-Brennstoffzellensystems zur Hausenergieversorgung mit Dampfreformer

    Brandt, H.


    The first development cycle of a residential power generation system is described. A steam reformer was chosen to produce hydrogen out of natural gas. After carbon monoxide purification with a preferential oxidation (PrOx) unit the hydrogen rich reformat gas is feed to the anode of the PEM-fuel cell, where due to the internal reaction with air oxygen form the cathode side water, heat and electricity is produced. Due to an incomplete conversion the anode off gas contains hydrogen and residual methane, which is feed to the burner of the steam reformer to reduce the needed amount of external fuel to heat the steam reformer. To develop the system the components are separately investigated and optimized in their construction or operation to meet the system requirements. After steady state and dynamic characterization of the components they were coupled one after another to build the system. To operate the system a system control was developed to operate and characterize this complex system. After characterization the system was analyzed for further optimization. During the development of the system inventions like a water cooled PrOx, an independent fuel cell controller or a burner for anodic off gas recirculation were made. The work gives a look into the interactions between the components and allows to understand the problems by coupling such components. (orig.)

  11. Identification and characterization of a highly variable region in mitochondrial genomes of fusarium species and analysis of power generation from microbial fuel cells

    Hamzah, Haider Mousa

    In the microbial fuel cell (MFC) project, power generation from Shewanella oneidensis MR-1 was analyzed looking for a novel system for both energy generation and sustainability. The results suggest the possibility of generating electricity from different organic substances, which include agricultural and industrial by-products. Shewanella oneidensis MR-1 generates usable electrons at 30°C using both submerged and solid state cultures. In the MFC biocathode experiment, most of the CO2 generated at the anodic chamber was converted into bicarbonate due the activity of carbonic anhydrase (CA) of the Gluconobacter sp.33 strain. These findings demonstrate the possibility of generation of electricity while at the same time allowing the biomimetic sequestration of CO2 using bacterial CA. In the mitochondrial genomes project, the filamentous fungal species Fusarium oxysporum was used as a model. This species causes wilt of several important agricultural crops. A previous study revealed that a highly variable region (HVR) in the mitochondrial DNA (mtDNA) of three species of Fusarium contained a large, variable unidentified open reading frame (LV-uORF). Using specific primers for two regions of the LV-uORF, six strains were found to contain the ORF by PCR and database searches identified 18 other strains outside of the Fusarium oxysporum species complex. The LV-uORF was also identified in three isolates of the F. oxysporum species complex. Interestingly, several F. oxysporum isolates lack the LV-uORF and instead contain 13 ORFs in the HVR, nine of which are unidentified. The high GC content and codon usage of the LV-uORF indicate that it did not co-evolve with other mt genes and was horizontally acquired and was introduced to the Fusarium lineage prior to speciation. The nonsynonymous/synonymous (dN/dS) ratio of the LV-uORFs (0.43) suggests it is under purifying selection and the putative polypeptide is predicted to be located in the mitochondrial membrane. Growth assays

  12. Nanostructured electrodes for Solar Power Generation Project

    National Aeronautics and Space Administration — The key to achieving high-power solar arrays for NASA applications is the development of high-efficiency, thin-film solar cells that can be fabricated directly on...

  13. Conditional prediction intervals of wind power generation

    Pinson, Pierre; Kariniotakis, Georges


    A generic method for the providing of prediction intervals of wind power generation is described. Prediction intervals complement the more common wind power point forecasts, by giving a range of potential outcomes for a given probability, their so-called nominal coverage rate. Ideally they inform...... integrate expertise on the characteristics of prediction errors for providing conditional interval forecasts. By simultaneously generating prediction intervals with various nominal coverage rates, one obtains full predictive distributions of wind generation. Adapted resampling is applied here to the case of...

  14. Power Generation and Distribution via Distributed Coordination Control

    Kim, Byeong-Yeon; Oh, Kwang-Kyo; Ahn, Hyo-Sung


    This paper presents power coordination, power generation, and power flow control schemes for supply-demand balance in distributed grid networks. Consensus schemes using only local information are employed to generate power coordination, power generation and power flow control signals. For the supply-demand balance, it is required to determine the amount of power needed at each distributed power node. Also due to the different power generation capacities of each power node, coordination of pow...

  15. Certification of power generation from sewage gas

    This article discusses the certification of power generated from sewage gas in packaged co-generation units in Switzerland. Since 2003, such electricity can be sold as 'green power' to consumers, who pay an additional charge for this ecologically generated power. Since the eco-balance of this electricity generated in wastewater treatment plant is considered as being excellent, the prestigious 'Naturemade Star' label has been awarded to it. This label sets most stringent requirements. The Canius wastewater treatment plant in the 'Lenzerheide' in eastern Switzerland is taken as an example to illustrate the procedure that has to be gone through to receive certification. This certification is carried out by independent auditors and guarantees that the 'green' electricity offered by the utility meets the high ecological criteria set by the label

  16. NaBH4 (sodium borohydride) hydrogen generator with a volume-exchange fuel tank for small unmanned aerial vehicles powered by a PEM (proton exchange membrane) fuel cell

    A proton exchange membrane fuel cell system integrated with a NaBH4 (sodium borohydride) hydrogen generator was developed for small UAVs (unmanned aerial vehicles). The hydrogen generator was composed of a catalytic reactor, liquid pump and volume-exchange fuel tank, where the fuel and spent fuel exchange the volume within a single fuel tank. Co–B catalyst supported on a porous ceramic material was used to generate hydrogen from the NaBH4 solution. Considering the power consumption according to the mission profile of a UAV, the power output of the fuel cell and auxiliary battery was distributed passively as an electrical load. A blended wing-body was selected considering the fuel efficiency and carrying capability of fuel cell components. First, the fuel cell stack and hydrogen generator were evaluated under the operating conditions, and integrated into the airframe. The ground test of the complete fuel cell UAV was performed under a range of load conditions. Finally, the fuel cell powered flight test was made for 1 h. The volume-exchange fuel tank minimized the fuel sloshing and the change in center of gravity due to fuel consumption during the flight, so that much stable operation of the fuel cell system was validated at different flight modes. - Highlights: • PEMFC system with a NaBH4 hydrogen source was developed for small UAVs. • Volume-exchange fuel tank was used to reduce the size of the fuel cell system. • Passive power management was used for a stable power output during the flight. • BWB UAV was selected by taking the fuel cell integration into consideration. • Stable operation of the fuel cell system was verified from the flight test

  17. Economics of power generation from imported biomass

    Attention is paid to the economics of import of biomass to the Netherlands, and subsequent utilisation for power generation, as a means to reduce dependence on (imported) fossil fuels and to reduce CO2 emission. Import of wood to the extent of 40 PJ or more from Baltic and South American states seems to be readily achievable. Import of biomass has various advantages, not only for the European Union (reduced CO2 emissions) but also for the countries of origin (employment creation). However, possible disadvantages or risks should be taken into account. With that in mind, import of biomass from Baltic states seems very interesting, although it should be noted that in some of those countries the alternative of fuel-switching to biomass seems to be more cost-effective than import of biomass from those countries. Given the expected increase in inland biomass consumption in the Baltic countries and the potential substantial future demand for biomass in other Western European countries it is expected that the biomass supply from Baltic countries will not be sufficient to fulfill the demand. An early focus on import from other countries seems advisable. Several power generation options are available with short to medium term potential and long term potential. The margin between costs of biomass-fuelled power and of coal fired power will be smaller, due to substantial improvements in power generating efficiency and reductions of investment costs of options for power generation from biomass, notably Biomass Gasification Combined Cycle. 18 refs

  18. Flywheel-powered X-ray generator

    Siedband, M. P.


    The use of a small flywheel appears to be a practical alternative to other power sources for mobile X-ray system applications. A 5 kg flywheel has been constructed which runs at 10 krpm and stores 30 KJ while requiring less than 500 W to bring the system up to speed. The wheel is coupled to an aircraft alternator and can yield pulsed power levels over 50 KWp. The aircraft alternator has the advantage of high frequency output which has also permitted the design of smaller high voltage transformers. A series of optical sensors detecting shaft position function as an electronic commutator so that the alternator may operate as a motor to bring the wheel up to operating speed. The system permits the generation of extremely powerful X-rays from a variety of low power sources such as household power outlets, automobile batteries or sources of poorly regulated electrical power such as those found in third world countries.

  19. LPGC, Levelized Steam Electric Power Generator Cost

    1 - Description of program or function: LPGC is a set of nine microcomputer programs for estimating power generation costs for large steam-electric power plants. These programs permit rapid evaluation using various sets of economic and technical ground rules. The levelized power generation costs calculated may be used to compare the relative economics of nuclear and coal-fired plants based on life-cycle costs. Cost calculations include capital investment cost, operation and maintenance cost, fuel cycle cost, decommissioning cost, and total levelized power generation cost. These programs can be used for quick analyses of power generation costs using alternative economic parameters, such as interest rate, escalation rate, inflation rate, plant lead times, capacity factor, fuel prices, etc. The two major types of electric generating plants considered are pressurized-water reactor (PWR) and pulverized coal-fired plants. Data are also provided for the Large Scale Prototype Breeder (LSPB) type liquid metal reactor. Costs for plant having either one or two units may be obtained. 2 - Method of solution: LPGC consists of nine individual menu-driven programs controlled by a driver program, MAINPWR. The individual programs are PLANTCAP, for calculating capital investment costs; NUCLOM, for determining operation and maintenance (O and M) costs for nuclear plants; COALOM, for computing O and M costs for coal-fired plants; NFUEL, for calculating levelized fuel costs for nuclear plants; COALCOST, for determining levelized fuel costs for coal-fired plants; FCRATE, for computing the fixed charge rate on the capital investment; LEVEL, for calculating levelized power generation costs; CAPITAL, for determining capitalized cost from overnight cost; and MASSGEN, for generating, deleting, or changing fuel cycle mass balance data for use with NFUEL. LPGC has three modes of operation. In the first, each individual code can be executed independently to determine one aspect of the total

  20. Microfabricated thermoelectric power-generation devices

    Fleurial, Jean-Pierre (Inventor); Ryan, Margaret A. (Inventor); Borshchevsky, Alex (Inventor); Phillips, Wayne (Inventor); Kolawa, Elizabeth A. (Inventor); Snyder, G. Jeffrey (Inventor); Caillat, Thierry (Inventor); Kascich, Thorsten (Inventor); Mueller, Peter (Inventor)


    A device for generating power to run an electronic component. The device includes a heat-conducting substrate (composed, e.g., of diamond or another high thermal conductivity material) disposed in thermal contact with a high temperature region. During operation, heat flows from the high temperature region into the heat-conducting substrate, from which the heat flows into the electrical power generator. A thermoelectric material (e.g., a BiTe alloy-based film or other thermoelectric material) is placed in thermal contact with the heat-conducting substrate. A low temperature region is located on the side of the thermoelectric material opposite that of the high temperature region. The thermal gradient generates electrical power and drives an electrical component.

  1. Fast generation of dendritic cells

    Kvistborg, P; Bøgh, Marie; Claesson, M H; Pedersen, A W


    Dendritic cells (DC) are potent antigen presenting cells capable of inducing immune responses. DC are widely used as vaccine adjuvant in experimental clinical settings. DC-based vaccines are normally generated using a standard 8day DC protocol (SDDC). In attempts to shorten the vaccine production...

  2. Hydropower generator and power system interaction

    Bladh, Johan


    After decades of routine operation, the hydropower industry faces new challenges. Large-scale integration of other renewable sources of generation in the power system accentuates the role of hydropower as a regulating resource. At the same time, an extensive reinvestment programme has commenced where many old components and apparatus are being refurbished or replaced. Introduction of new technical solutions in existing power plants requires good systems knowledge and careful consideration. Im...

  3. Bipolar high voltage pulse power generator

    Lukeš, Petr; Člupek, Martin; Babický, Václav; Šunka, Pavel

    Monterey : IEEE, 2007 - (Maenchen, J.; Schamiloglu, E.), s. 1061-1064 ISBN 0-7803-9190-X. [IEEE International Pulsed Power Conference/15th./. Portola Plaza Hotel, Monterey (US), 13.06.2005-17.06.2005] R&D Projects: GA AV ČR KSK2043105 Institutional research plan: CEZ:AV0Z20430508 Keywords : bipolar * pulse power generator * corona discharge Subject RIV: BL - Plasma and Gas Discharge Physics

  4. Smart Grid Technologies: Next Generation Power Sy

    Jyotsna P. Gabhane; Manisha N.Nimbalkar; Tejal Irkhede


    In the next-generation electric power systems that incorporate diversified renewable energy resources, automated and intelligent management is a critical component that determines the effectiveness and efficiency of these power systems. The management automation and intelligence are envisioned to offer a variety of advantages over the current systems in terms of digitalization, flexibility, intelligence, resilience, sustainability, and customization, which entitles the name Smart Grid to the ...

  5. On reliability optimization for power generation systems


    The reliability level of a power generation system is an important problem which is concerned by both electricity producers and electricity consumers. Why? It is known that the high reliability level may result in additional utility cost, and the low reliability level may result in additional consumer's cost, so the optimum reliability level should be determined such that the total cost can reach its minimum. Four optimization models for power generation system reliability are constructed, and the proven efficient solutions for these models are also given.

  6. Mechanism of power generation - the MHD way

    The basic physical principles of magnetohydrodynamics and the application of this principle for power generation (direct energy conversion) are explained. A magnetohydrodynamic generator (MHDG) is described both in the Faraday and Hall modes. The advantages of the Faraday mode and the Hall mode for different geometries of the generator are mentioned. The conductor used is a fluid - an ionised gas (plasma) or a liquid metal at high temperature. The difficulties in maintaining high temperature and high velocity for the gas and very low temperature at the same time side by side for superconducting magnets to produce a strong magnetic field, are pointed out. The most commonly used gas is purified air. The advantages of MHD generators and the present power crisis have compelled further research in this field in spite of the high costs involved. (A.K.)

  7. Power generator system for HCL reaction

    A power generation system includes a nuclear reactor having a core which in addition to generating heat generates a high frequency electromagnetic radiation. An electromagnetic radiation chamber is positioned to receive at least a portion of the radiation generated by the reactor core. Hydrogen and chlorine are connected into the electromagnetic reactor chamber and react with controlled explosive violence when exposed to the radiation from the nuclear reactor. Oxygen is fed into the reactor chamber as a control medium. The resulting gases under high pressure and temperature are utilized to drive a gas turbine generators. In an alternative embodiment the highly ionized gases, hydrogen and chlorine are utilized as a fluid medium for use in magnetohydrodynamic generators which are attached to the electromagnetic reactor chambers

  8. Globally Secured Power Generation through Vibration

    Nimika Aggarwal


    Full Text Available Global security is an important basis of the entire human security system. Since Industry revolution, human began to suffer from many kinds of pollution and ecosystem degradation, such as air pollution, water pollution, soil loss and degradation, etc. The need to generate power (or say electricity is the demand for today’s life because of the fact that even if there is a lot of medium to generate power then there are lot of medium for pollution as well so there would still be a shortage of clean electricity. Comparison of different forms of commercial power generation by use of the fuel cycle methods developed in European studies shows that the health burdens are extreme in areas where power stations (based on coal, Ignite, and oil are situated as they pollute the outdoor air to large extent therefore one has to overcome this state. This paper reviews the state of knowledge regarding the generation of electricity by pressure or vibration produced by our footsteps which make the generation eco-friendly and easy.

  9. Electricity generation and microbial community structure of air-cathode microbial fuel cells powered with the organic fraction of municipal solid waste and inoculated with different seeds

    El-Chakhtoura, Joline


    The organic fraction of municipal solid waste (OFMSW), normally exceeding 60% of the waste stream in developing countries, could constitute a valuable source of feed for microbial fuel cells (MFCs). This study tested the start-up of two sets of OFMSW-fed air-cathode MFCs inoculated with wastewater sludge or cattle manure. The maximum power density obtained was 123±41mWm-2 in the manure-seeded MFCs and 116±29mWm-2 in the wastewater-seeded MFCs. Coulombic efficiencies ranged between 24±5% (manure-seeded MFCs) and 23±2% (wastewater-seeded MFCs). Chemical oxygen demand removal was >86% in all the MFCs and carbohydrate removal >98%. Microbial community analysis using 16S rRNA gene pyrosequencing demonstrated the dominance of the phylum Firmicutes (67%) on the anode suggesting the possible role of members of this phylum in electricity generation. Principal coordinate analysis showed that the microbial community structure in replicate MFCs converged regardless of the inoculum source. This study demonstrates efficient electricity production coupled with organic treatment in OFMSW-fueled MFCs inoculated with manure or wastewater. © 2014 Elsevier Ltd.

  10. Iron-nitrogen-activated carbon as cathode catalyst to improve the power generation of single-chamber air-cathode microbial fuel cells.

    Pan, Yajun; Mo, Xiaoping; Li, Kexun; Pu, Liangtao; Liu, Di; Yang, Tingting


    In order to improve the performance of microbial fuel cell (MFC), iron-nitrogen-activated carbon (Fe-N-C) as an excellent oxygen reduction reaction (ORR) catalyst was prepared here using commercial activated carbon (AC) as matrix and employed in single chamber MFC. In MFC, the maximum power density increased to 2437±55mWm(-2), which was 2 times of that with AC. The open circuit potential (OCP) of Fe-N-C cathode (0.47) was much higher than that of AC cathode (0.21V). The R0 of Fe-N-C decreased by 47% from 14.36Ω (AC) to 7.6Ω (Fe-N-C). From X-ray photoelectron spectroscopy (XPS), pyridinic nitrogen, quaternary nitrogen and iron species were present, which played an important role in the ORR performance of Fe-N-C. These results demonstrated that the as-prepared Fe-N-C material provided a potential alternative to Pt in AC air cathode MFC for relatively desirable energy generation and wastewater treatment. PMID:26898678

  11. Power generation alternatives for the XXI century

    Forecasts from different specialized sources indicate that the power consumption in the world will continue to increase. In Argentina it is expected that for the year 2020 the consumption will double the present values. In 2003, in our country, fossil fuels - carbon, oil, gas - contributed approximately 48% to the power generation, while hydroelectricity was 43% and nuclear power 9%. Fossil fuels have some advantages, main ones are present low cost and easy transport, but they have also many disadvantages in terms of contamination, environmental effects and non-renewable resources. The Carbon Dioxide (CO2), that is produced when burning fossil fuels, is considered as one of the major sources of global warming in earth (Greenhouse effect), with devastating climate consequences in certain regions as dry seasons, floods etc. In Argentina total CO2 emissions in year 1998 (last measured) were 114 million Tons. Although absolute emission values are not high, when compared with those of certain developed countries, some mitigation measures could be adopted. Emissions due to transport are diminishing thanks to a strong reconversion of public and private vehicles to run on natural gas instead of gasoline or diesel. But what are we going to do to optimize Power Generation lowering fossil fuels consumption? Some environmental NGO's insist that the only solution is to use the 'so called' renewable energies - Solar, Wind, Biomas, Geothermal - but these sources contribute only with less than 0,03% to Power Generation in our country. Figures provided by the World Energy Council shows that only 2% of Power used commercially all around the world comes from 'renewables'. Although this output could be increased in the future, WEC estimates very difficult to reach even 5% for year 2020 Solar energy is employed successfully in some countries to heat water for household purposes or to produce little amount of electricity for specific purposes. It is tempting to think that wind and sun

  12. PEOPLE - The cutting edge in power generation

    As competition for the United States power consumer increases, generating companies must seek new ways to do business. One way to keep up with the pace of change is to implement unique ideas into various areas of daily operation at the generating station. From subtle new management styles to ambitious employee education programs, changes in operating the management techniques can produce valuable results over time. An educated confident workforce is capable of vast improvement in efficiency and technical competence. We become empowered

  13. Controller For Standalone Hybrid Renewable Power Generation

    P. Madhu Prabhuraj #1 R.M. Sasiraja


    The project utilizes the resources available locally like sunlight, wind and biogas plant which can be installed with aids from government. A controller is designed to switch between generation sources with preference to renewable modes. When renewable energy is excess, the biogas is shut down and the power is used to pump water to a higher level, which can later be used for agriculture and micro hydro generation. In the hybrid system, energy has a higher reliability, can be cost effective an...

  14. Contribution to MPC coordination of distributed and power generation systems

    Sandoval Moreno, John Anderson


    This thesis is mainly about coordination of distributed systems, with a special attention to multi-energy electric power generation ones. For purposes of optimality, as well as constraint enforcement, Model Predictive Control (MPC) is chosen as the underlying tool, while wind turbines, fuel cells, photovoltaic panels, and hydroelectric plants are mostly considered as power sources to be controlled and coordinated. In the first place, an application of MPC to a micro-grid system is proposed, i...

  15. Joint venture power generation - a successful experiment

    In order to boost the development plans and to maintain the pace of economic activities, a strong need was felt to find out alternative ways and means for setting up new power generation projects to meet the rapidly growing demand. The most feasible way to overcome above difficulties, to a great extent, is to establish a power plant by joining of hands by a group of continuous process industries situated in some industrial area. One such experiment of setting up joint power plant has, very successfully, been carried out. A glance at the experiment in retrospect would be interesting. (author)

  16. Development of low grade waste heat thermoelectric power generator

    Suvit Punnachaiya; Paiboon Kovitcharoenkul; Decho Thong-aram


    This research aimed to develop a 50 watt thermoelectric power generator using low grade waste heat as a heat source,in order to recover and utilize the excess heat in cooling systems of industrial processes and high activity radioisotope sources. Electricity generation was based on the reverse operation of a thermoelectric cooling (TEC) device. The TEC devices weremodified and assembled into a set of thermal cell modules operating at a temperature less than 100°C. The developed powergenerator...


    Mustafa ENGİN; Metin ÇOLAK


    In this paper, a solar-wind hybrid power generating, system that will be used for security lighting was designed. Hybrid system was installed and solar cells, wind turbine, battery bank, charge regulators and inverter performance values were measured through the whole year. Using measured values of overall system efficiency, reliability, demanded energy cost per kWh were calculated, and percentage of generated energy according to resources were defined. We also include in the paper a discussi...

  18. Optimal power flow for distribution networks with distributed generation

    Radosavljević Jordan; Jevtić Miroljub; Klimenta Dardan; Arsić Nebojša


    This paper presents a genetic algorithm (GA) based approach for the solution of the optimal power flow (OPF) in distribution networks with distributed generation (DG) units, including fuel cells, micro turbines, diesel generators, photovoltaic systems and wind turbines. The OPF is formulated as a nonlinear multi-objective optimization problem with equality and inequality constraints. Due to the stochastic nature of energy produced from renewable sources, i....

  19. Unconventional systems for lunar base power generation and storage

    Recent advances in thin film solar photovoltaic converters (PV's) can furnish multimegawatt power levels during lunar daylight periods with only modest mass requirements. The extended duration of lunar night (ca. 354 hr) and the high specific mass of earth-imported energy storage systems (regenerative fuel cells, batteries, etc.) render PV plus import storage power systems non-competitive with nuclear power plants for lunar bases. However, power storage or generation methods which can be constructed using primarily lunar materials, used either alone or with lightweight PV's, can be attractive alternatives to nuclear power. Three separate generic systems which can provide favorable low import mass goals have been identified and studied. These are: gravitational energy generation using lunar soil, thermal energy storage using basalt rock or glass, and electrochemical storage using lunar derived electrodes or fuels. Design, structural and operational features of these methods are described

  20. Microelectromechanical power generator and vibration sensor

    Roesler, Alexander W.; Christenson, Todd R.


    A microelectromechanical (MEM) apparatus is disclosed which can be used to generate electrical power in response to an external source of vibrations, or to sense the vibrations and generate an electrical output voltage in response thereto. The MEM apparatus utilizes a meandering electrical pickup located near a shuttle which holds a plurality of permanent magnets. Upon movement of the shuttle in response to vibrations coupled thereto, the permanent magnets move in a direction substantially parallel to the meandering electrical pickup, and this generates a voltage across the meandering electrical pickup. The MEM apparatus can be fabricated by LIGA or micromachining.

  1. Green power perspectives on sustainable electricity generation

    Neiva de Figueiredo, Joao


    Green Power: Perspectives on Sustainable Electricity Generation; João Neiva de Figueiredo and Mauro GuillénAn Overview of Electricity Generation Sources; Akhil Jariwala and Saumil JariwalaGermany's Energy Revolution; José Carlos Thomaz, Jr. and Sean MichalsonChina's Energy Profile and the Importance of Coal; Julia Zheng and Xiaoting ZhengChina's Search for Cleaner Electricity Generation Alternatives; Julia Zheng and Xiaoting ZhengRenewable Energy in Spain: A Quest for Energy Security; José Normando Bezerra, Jr.Renewable Energy in French Polynesia: From Unpredictable to Energy Independence? Dia

  2. Wind power generation and dispatch in competitive power markets

    Abreu, Lisias

    Wind energy is currently the fastest growing type of renewable energy. The main motivation is led by more strict emission constraints and higher fuel prices. In addition, recent developments in wind turbine technology and financial incentives have made wind energy technically and economically viable almost anywhere. In restructured power systems, reliable and economical operation of power systems are the two main objectives for the ISO. The ability to control the output of wind turbines is limited and the capacity of a wind farm changes according to wind speeds. Since this type of generation has no production costs, all production is taken by the system. Although, insufficient operational planning of power systems considering wind generation could result in higher system operation costs and off-peak transmission congestions. In addition, a GENCO can participate in short-term power markets in restructured power systems. The goal of a GENCO is to sell energy in such a way that would maximize its profitability. However, due to market price fluctuations and wind forecasting errors, it is essential for the wind GENCO to keep its financial risk at an acceptable level when constituting market bidding strategies. This dissertation discusses assumptions, functions, and methodologies that optimize short-term operations of power systems considering wind energy, and that optimize bidding strategies for wind producers in short-term markets. This dissertation also discusses uncertainties associated with electricity market environment and wind power forecasting that can expose market participants to a significant risk level when managing the tradeoff between profitability and risk.

  3. Magnetic field generation device for magnetohydrodynamic electric power generation

    An existent magnetic field generation device for magnetohydrodynamic electric power generation comprises at least a pair of permanent magnets disposed to an inner circumferential surface of a yoke having such a cross sectional area that two pairs of parallel sides are present, in which different magnetic poles are opposed while interposing a flow channel for a conductive fluid therebetween. Then, first permanent magnets which generate main magnetic fields are disposed each at a gap sandwiching a plane surface including a center axis of a flow channel for the conductive fluid. Second permanent magnets which generate auxiliary magnetic fields are disposed to an inner circumferential surface of a yoke intersecting the yoke to which the first permanent magnets are disposed. The magnetic poles on the side of the flow channel for the second permanent magnets have identical polarity with that of the magnetic poles of the adjacent first permanent magnets. As a result, a magnetic flux density in the flow channel for the conductive fluid can be kept homogeneous and at a high level from a position of the axial line of the flow channel to the outer circumference, thereby enabling to remarkably improve a power generation efficiency. (N.H.)

  4. Plasma plume MHD power generator and method

    Hammer, J.H.


    A method is described of generating power at a situs exposed to the solar wind which comprises creating at separate sources at the situs discrete plasma plumes extending in opposed directions, providing electrical communication between the plumes at their source and interposing a desired electrical load in the said electrical communication between the plumes.

  5. Economic analysis of nuclear power generation

    An energy security index was developed to measure how the introduction of nuclear power generation improved the national security of energy supply in Korea. Using the developed index, a quantitative effort was made to analyze the relationship between the nuclear power generation and the national energy security. Environmental impacts were evaluated and a simplified external cost of a specific coal-fired power plant in Korea was estimated using the QUERI program, which was developed by IAEA. In doing so, efforts were made to quantify the health impacts such as mortality, morbidity, and respiratory hospital admissions due to particulates, SOx, and Nox. The effects of CO2 emission regulation on the national economy were evaluated. In doing so, the introduction of carbon tax was assumed. Several scenarios were established about the share of nuclear power generation and an effort was made to see how much contribution nuclear energy could make to lessen the burden of the regulation on the national economy. This study re-evaluated the methods for estimating and distributing decommissioning cost of nuclear power plant over lifetime. It was resulted out that the annual decommissioning deposit and consequently, the annual decommissioning cost could vary significantly depending on estimating and distributing methods. (author). 24 refs., 44 tabs., 9 figs

  6. On risk of nuclear power generation

    When energy consumption becomes high and industrial activities become active, the risk of the death due to traffic accidents and work place accidents becomes high. On the other hand, if energy consumption is very low, and industrial activities are not active, there is the demerit or risk that human life becomes short as the result. In this study, on the viewpoint of the effects that poverty, electric power generation, nuclear reactor accidents, various disasters and spreading diseases exert to human life, the risks were determined quantitatively, and the risk of nuclear power generation was investigated by comparing it with other risks. When the relation of the energy consumption per one person with human life was investigated in various countries, there was considerably good correlation. In order to clarify the factors that exert influence to average life, the survival number curves of now and in the past were discussed on their change. The effects on average human life of poverty, the atmospheric contamination caused by power stations, the serious accidents in nuclear power stations such as that in Chernobyl, unexpected disasters such as Great Hanshin Earthquake and spreading diseases are reported. The comparison of the risk of nuclear power generation with other risks is shown. (K.I.)

  7. Nitrate as an Oxidant in the Cathode Chamber of a Microbial Fuel Cell for Both Power Generation and Nutrient Removal Purposes

    Fang, Cheng; Min, Booki; Angelidaki, Irini


    operation without catalyst. Nitrate was reduced to nitrite and ammonia in the liquid phase at a ratio of 0.6% and 51.8% of the total nitrate amount. These results suggest that nitrate can be successfully used as an oxidant for power generation without aeration and also nitrate removal from water in MFC...

  8. Comprehensive standards: the power generation case

    This study presents an illustrative data base of material quantities and environmental effluents in the fuel cycles for alternative technologies of thermally generated power. The entire fuel cycle for each of the alternative ten technologies is outlined for a representative power plant generating 1000 Mw of electrical power. The required utilization of material resources and the fuel-cycle material quantities are indicated on a flow sheet for each technology. The technologies considered are: (1) Light Water Nuclear Reactor; (2)Coal: Appalachian Bituminous and Northwestern Sub-bituminous; (3) Residual fuel oil; (4) Natural Gas; (5) High Sulfur Coal, with Coal Gasification and Sulfur Removal; (6) High Sulfur Coal, with SO2 recovery by Wet-Limestone Scrubbing; (7) Geothermal Steam; (8) Breeder Fission Reactor; (9) Solar Energy; and (10) Thermonuclear Fusion

  9. Optical generation of radio-frequency power

    An optical technique for high-power radio-frequency (RF) signal generation is described. The technique uses a unique photodetector based on a traveling-wave design driven by an appropriately modulated light source. The traveling-wave photodetector (TWPD) exhibits simultaneously a theoretical quantum efficiency approaching 100 % and a very large electrical bandwidth. Additionally, it is capable of dissipating the high-power levels required for the RF generation technique. The modulated light source is formed by either the beating together of two lasers or by the direct modulation of a light source. A system example is given which predicts RF power levels of 100's of mW's at millimeter wave frequencies with a theoretical ''wall-plug'' efficiency approaching 34%

  10. Feasibility of wind power generation in Ghana

    Technical appraisal, cost-benefit analysis, energy payback time and energy ratio have been examined to assess the feasibility of wind power generation in Ghana. At a site of average wind speed of 6.23 m/s and a height of 30 m, a 7.5 kW turbine of up-wind horizontal rotor of 6.3 m diameter produced 17.65 MW-h of energy. For payback period of 10 years, the projected cost of the energy produced by a single turbine was estimated to be GHC 0.30 (∼ 20 cents) per kWh (compared to 14 cents/kWh for photovoltaic generation and 10 cents/kWh for solar thermal), which therefore makes large scale optimized wind power generation competitive in Ghana (each renewable energy conversion system requires very high initial capital investment). For the wind aero-generation system of 20 years life span, the energy ratio estimated was 2.1; indicating that wind power generation is a feasible investment project. A computer code was developed for the financial analysis and to predict the net present value of the investment depending on the prevailing cost indices. (au)