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used to assist industry in its efforts to bring photovoltaic technology to competitive maturity, domestically and internationally.

Solar Thermal Technology

The technology base for solar thermal technology has dramatically improved as a result of significant achievements within the last two years. These achievements include substantial system cost reductions and performance enhancement due to the research in advanced solar thermal components and subsystems which resulted, in part, from DOE's cooperative efforts with industry. At present, solar thermal technologies are capable of delivering electricity at 13¢/kWhe. However, solar thermal technology must be capable of 5¢/kWhe for electric power production and $9/MBtu for thermal energy in order to be competitive with a mix of other energy generating technologies. The FY 1987 program, with a budget request of $15.3 million for operating expenses, emphasizes activities which address the component and subsystem improvements/advances necessary to approach these objectives. Heliostat sizes have increased three to four-fold, while costs have been reduced by 40% since Solar One (Barstow) became operational in 1982. The stretched membrane concept has the potential to further reduce the heliostat field and parabolic dish concentrator costs by another 50%. The FY 1987 research will continue the design and testing of these advanced concepts.

Central receivers using molten salt or sodium as heat transfer fluids would allow reductions in the size of advanced receivers and enable the development of low pressure receivers that are lighter in weight with lighter support structures. The new fluids can also be stored at high temperature and

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low pressure for plant operation during long hours of reduced insolation. Research efforts in this area to-date have established the basis for reduced receiver and storage costs by 50%, improving both the overall plant cost and levelized energy costs of solar thermal systems. The development and testing of these advanced subsystems will continue through FY 1987. The Vanguard dish module has proven the high conversion efficiency of sunlight to electricity by achieving a 29% net (31% gross) system efficiency using a kinematic Stirling engine. Development of the free-piston Stirling engine concept, in cooperation with NASA, will continue in FY 1987. This engine has the potential to achieve the long-term goals of high reliability and performance at competitive cost. Additional research projects which are underway and will continue in FY 1987 include the development of a thermochemical cell in which spent chemicals would be regenerated by solar energy to produce electricity. Additionally, several present methods for producing solar thermal electricity generating systems are limited to operation below 750°F due to excessive thermal losses. Researchers will continue to study approaches for replacing the sensible heat transport methods with thermochemical energy transport and storage processes which have the potential to dramatically reduce thermodynamic losses and thereby increase overall efficiency. Experiments addressing the technical feasibility of thermochemical transport will also be undertaken.

Biofuels

Biofuels energy technologies utilize a variety of organic feedstocks,

such as terrestrial and aquatic crops and municipal waste, which can be converted by thermochemical and biochemical processes into high-value gaseous,

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liquid, and solid fuels. Biofuels currently are supplying approximately 2.7 quads or almost 4% to the U.S. energy supply. Development of advanced biofuels technologies offers the potential for significant additional contributions over the longer term. The FY 1987 budget request for Biofuels Energy Systems is $11.6 million for operating expenses and $0.6 million for capital equipment. During FY 1987, the Biofuels Program will focus on key long-range research and development issues to provide a technology base for private sector development of biofuels production and conversion technologies.

Feedstock production research supported within the Budget Request in shortrotation intensive culture will include genetic selection to improve biomass yields, along with examination of monoculture plantings to determine operational yields and susceptibility to disease and pests. Research on herbaceous energy crops will focus on screening of promising species which can be grown on marginal croplands, as well as small-scale experimental plots. Aquatic species research will include species screening, genetic research, and small-scale experiments to improve the productivity of microalgal species and the efficiency of conversion processes.

Thermochemical conversion research will focus on liquefaction and pyrolysis of biomass feedstocks to produce high-value liquid and gaseous fuels. Municipal solid waste research will continue to address the production of liquid and gaseous fuels via thermal liquefaction and gasification. Combustion kinetics and emissions research will also be conducted.

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Research in biochemical conversion will focus on improving processes for conversion of organic materials to alcohol fuels in order to advance the technology for competitive production of octane enhancers and additives for transportation fuels. Research in the anaerobic digestion of municipal waste will address the improvement of microorganisms, as well as attempt to understand the biochemistry and physiology of the anaerobic digestion process.

Wind Energy

Updated information, recently received, indicates that there are presently over 13,000 wind turbines operating in the U.S. with an installed capacity greater than 1100 MW. However, many areas remain where continued research efforts are needed to establish the knowledge base necessary for industrial development of viable wind technology within the context of evolving competitive and unsubsidized electric energy supply markets. It is the objective of the Wind Energy Research Program to improve the understanding of fundamental atmospheric fluid flows and their effects on wind turbines and to translate this understanding into tools that industry can use to design and develop improved, more reliable, cost competitive wind turbines. The FY 1987 budget request of $8.1 million for operating expenses and $.2 million for capital equipment will fund the research required to accomplish these objectives.

Commercial development which started at the 50 kw size has now moved into the 100-200 kw range. With the success of those tests and the current successful operation of the larger Mod-2 experiments, sufficient data is now available to industry to proceed with larger systems. The large experimental Mod-2 and

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Mod-5 projects will be closed in FY 1987 to concentrate resources on fundamental structural and aerodynamic research to benefit all system sizes.

Major improvements in turbine energy capture are believed to be achievable through aerodynamics research activities. Tests on specially instrumented commercial machines will continue in order to collect actual operating data in a wide range of environments. This will improve the understanding of the performance of different turbines' energy capture as it is affected by turbulence, wakes, and micro-siting and will further the development of air foils tailored to wind turbine requirements.

FY 1987 structural dynamics research activities will improve the understanding of how aerodynamic loads induce structural stresses and rotor and tower material fatigue. Research efforts are aimed at the development of predictive models which take into account the complex interactions of forces on wind machines. Cooperative field assessment activities with industry are used in this area to acquire the data necessary to verify theories.

Advanced component development involves the application of basic science and research on aero and structural dynamics to develop components that could lead to major improvements in the energy production of advanced wind turbines. This area also includes studies on environmental effects of wind turbines, application of wind turbines as fuel savers with diesel generators for remote power generation, and on the interaction of wind machines with existing utility power systems.