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of analytical tools to allow architects and engineers to predict system performance. Researchers will also continue to monitor, analyze, and evaluate the performance and reliability of solar building technology. Analysis techniques are being developed for lategrating these solar technologies with conventional heating and cooling systems.

PHOTOVOLTAICS

Photovoltaics (PV) 18 on its way to becoming a significant energy supply option. The partnership between DOE and industry has resulted to date in

rising conversion efficiencies, increasing reliability, and lower costs, all

of which have helped the technology to establish a strong foothold in the

competitive energy market, with a broad range of viable applications. In FY 1987 the Photovoltaic Program, with a budget request of $19.6 million for operating expenses and $1.0 million for capital expenses, will seek to advance the basic understanding of technical 188ues associated with materials formation and physical phenomena of the PV cell.

Amorphous silicon 18 an attractive thia-film photovoltaic material that could establish PV technology as a broadly competitive electric power production option. U.S. research leads worldwide efforts in addressing the issues leading to the optimization of single junction submodules and the Investigation of higher efficiency multifunction concepts. The efforts will lay the ground work for a viable industrial effort capable of achieving 10 percent efficiency single Junction and 13 percent multiple Junction large

area submodules.

Polycrystalline thin films also represent promising candidates for meeting

the major programmatic criteria relating to cell efficiency, material processing requirements, and performance stability. Progress has been made

in the development of low cost deposition methods, and in cell efficiency.

PY 1987 efforts will concentrate on defining the scientific and technological barriers to approaching theoretical efficiency and on the development of large area fila fabrication concepto for the most promising of these

uterials.

As a result of DOE's program, single-crystal gallium arsenide and

single-crystal silicon solar cells currently hold records for the most efficient photovoltaic conversion of sunlight to electricity. But the efficiency of such materials 18 inherently limited because not all incident sunlight can be utilized due to the frequency selectivity of the specific nateriais involved. To overcome this difficulty, researchers are exploring concepts that will include seeking improvements in selected single-junction cells as well as studying concepts to mechanically or optically couple celle

or to fabricate, as one structure, two or more cells of different materials. The goal of this high priority effort in high efficiency concepts is to

achieve 35% efficient small area cells for use by industry as part of its

development effort.

The FY 1987 program will also maintain its unique capability for precise

measurement of material and cell parameters. This work at SERI guides researchers throughout the U.S. in understanding and correlating observed

physical phenomena. The program will also support other fundamental research

in quarternary and ternary compounds, and promote basic material work at

universities. Pinally, the wealth of information gathered by the progran

from materials to systems during its ten years of research and development will be used to assist industry in its efforts to bring photovoltaic technology to competitive naturity, 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 13c/kWhe.

However, solar thermal technology must be capable

of 5€/kWhe for electric power production and $9/MBtu for themal 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% siace 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 low

pressure for plant operation during long hours of reduced insolation. Re

search 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, 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

short-rotation intensive culture will include genetic selection to improve biomas8 yolds, 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 that 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

11quid and gaseous fuels via thermal liquefaction and gasification.

Combustion kinetics and emissions research will also be conducted.

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 laprovement 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 that started at the 50 kw size has now Roved into the 100-200 kw range. With the success of those tests and the current successful operation of the larger Mod-2 experimente, sufficient data 18 now available to Industry to proceed with larger systems. The large experimental Mod-2 and Mod-5 projects will be closed 10 FY 1987 to concentrate resources on

fundamental structual 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 la a wide range of environments. This will improve the understanding of the performance of different turbines' energy capture as it 18 affected by turbulence, wakes, and micro-biting and will further the development of air folls tailored to wind turbine requirements.

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