General Framework

The National PV Program works with the PV industry through cost-shared programs to develop and improve component designs, device manufacturability and systems. Education, technical transfer, technical assistance and competitive contracts were used extensively to accomplish the work in 2000. The U.S. Department of Energy web site (http://www.eren.doe.gov/pv/) provides information on and links to all aspects of the National PV Program. PV-related activities were balanced between PV cell and module development, manufacturing, system, and balance-of-system technologies.

PV-related manufacturers refined the Industry Roadmap in December 2000. The roadmap plan unifies the vision and long-term (2000-2020) strategies and goals for the PV industry. The vision provides the electrical/energy consumer competitive and environmentally friendly energy products and services from a thriving U.S.-based solar electric power industry. The National Photovoltaics Program Plan for 2000-2004 that was written in concert with the industry roadmap plan helps to guide the national program.

The National Center for Photovoltaics (NCPV), an alliance of organizations, serves as the focal point for the nation's capabilities in PV technologies and has proven to be an effective structure for planning and implementing the National PV Program. The National PV Program's R&D goals and strategies are formulated each year by its governing board in concert with the Industry Roadmap and through an all-encompassing annual operating plan.

PV technologies for both thin-film devices and crystalline devices continued partnership programs in 2000. The Thin-Film Partnership Program and the Crystalline Silicon Research Cooperative collaborated with manufacturers on technology issues that were common to all manufacturing processes and non-proprietary in nature to pool the nation's resources in order to maximize technology advancement. The U.S. Department of Energy also worked to reinforce the ongoing Million Solar Roofs Initiative with a goal to place one million PV and other solar energy systems on roofs by the year 2010.
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National Programme

• Research and Development 52% of budget
• Systems Engineering and Applications 24% of budget
• Technology Development 24% of budget

The total FY2000 federal budget for the National PV Program was authorized at USD 60,5 million dollars. Additional support for PV-related projects came from state and local governments, the PV industry, and utilities. Total industry cost share for contracts in the U.S. Department of Energy National PV Program was expected to be more than 32,5% of the total budget while some elements of the program saw greater than 50% cost share.

The NCPV relies on the core expertise of NREL and Sandia to create, develop, and deploy PV and related technologies. Other national PV resources that the NCPV draws on are Brookhaven National Laboratory, two Regional Experiment Stations (the Florida Solar Energy Center and the Southwest Technology Development Institute), and U.S. Department of Energy's Centers of Excellence in PV at the Georgia Institute of Technology and the University of Delaware (Institute of Energy Conversion). In addition, more than 180 university, industry and utility research partnerships across the country are linked together to function in a unified way. The NCPV awards most of its federal funds through competitive procurements to industry, universities, and other research centers around the country.
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Research and Development

Thin-film devices and materials development continued through the NCPV and Thin-film Partnership Program. Thin-film devices include amorphous silicon (a-Si), copper indium diselenide (CIS), copper indium gallium diselenide (CIGS), cadmium telluride (CdTe), thin-film silicon and others. The Thin-film Partnership Program helps to commercialize this promising technology. Among this year's achievements were efficiency records, gains in cell and module processing techniques, and new commercial production facilities. Responding to sustained research efforts, the efficiency of thin-film devices is steadily rising. In 2000, commercially available amorphous silicon (a-Si) modules showed stable efficiencies that were more than 7,2%; cadmium telluride (CdTe) modules that were rated 10,6% efficient; and CIS-based modules that were rated at more than 10% efficient.

• Research on amorphous silicon (a-Si)
  Research has moved efficiencies of a-Si devices toward the national goal of 13% efficiency and methods for increasing the deposition rate of a-Si were successful. Research produced a record low-defect-density deposition rate as high as 83 angstroms per second. The method used for the high deposition rate was hot-wire chemical deposition. The U.S. industrial capacity expanded to meet world-wide demand for a-Si products. United Solar Systems began construction of a new 25 MW manufacturing line in 2000. BP Solar now operates its 10 MW/year plant with enhanced throughput that produces tandem-junction, a-Si alloy modules in the 43 to 50 W range with glass-to-glass encapsulation.

• Research on cadmium telluride (CdTe)
  PV devices using CdTe can be manufactured using potentially low-cost techniques such as spraying, electrodeposition, and high-rate evaporation. Achieving high laboratory efficiencies using these low-cost techniques is an important objective of the National PV Program. To date, more than ten techniques have been used to grow CdTe layers resulting in cells operating at greater than 10%. Three of these methods are currently used in industry. BP Solar began production of a CdTe module with verified world-record aperture area efficiency of 10,6% and power output of 91,5 W. The changes in performance were the result of changes in the electro-deposition bath and a reduction in the thickness of the CdS film. The results also further the National PV Program 5-Year Plan milestone for a 10% CdTe-based module by 2004. First Solar, LLC has advanced its ultrahigh-rate vapor transport deposition through collaboration with the National PV Program. First Solar now produces CdTe plates at the rate of eight plates per minute in its new 100 MW per year plant.
  Commercial production of CdTe products progressed in 2000 as BP Solar, a participant in the Thin Film PV Partnership, fabricated modules made of thin-film CdTe material in its plant which was designed to produce up to 7 MW of CdTe modules per year.

• Research on Copper Indium Diselenide (CIS) and Copper-Indium-Gallium-Selenide (CIGS)
  Two major goals for CIS research are to transfer years of government-sponsored research on the technology to industry for pilot-scale manufacturing and to produce commercial modules with 10% efficiency. NREL scientists achieved replicable CIGS cells with efficiencies between 18,1 and 18,8% using a special plasma vapor deposition technique to sputter molybdenum onto the substrate used for CIGS deposition. Industry explored new deposition systems for large-area CIS devices. Co-evaporation of CdS/Cu(In,Ga)Se2 at the Institute of Energy Conversion produced solar cells with 14,9% efficiency. Two companies are now planning to use co-evaporation processes to produce CIS modules.
  Commercial products, using CIS alloys, were sold by Siemens Solar Industries (SSI) and by Global Solar in 2000. SSI produced 5- to 40-W PV modules made of CIS alloys that were more than 10% efficient. Global Solar produced flexible modules for a variety of field applications. SSI developed the new products using copper-indium-gallium-sulfurselenide (CIGSS) under contract to the Thin-film PV Partnership Program. Global Solar developed increased throughput of its CIGS modules via new high-speed scribing, integrated ink-jet hardware and high CIGS deposition rates.

• Research on crystalline silicon (c-Si) PV
  Because more than 90% of PV power systems sold today are made of crystalline silicon (c-Si), improvements to this technology have the potential for quick advancement to the marketplace. Fundamental research for scientific advances through the Crystalline Silicon Research Cooperative and other programs in crystalline silicon technologies continued in 2000. The program sponsored the 10th Workshop on Crystalline Silicon Materials and Processes to effectively communicate research results. In light of industry interest, a Cooperative Research and Development Agreement was established in 2000 to develop new direct-writing approaches to contact metalizations. The industry has set high priorities to the understanding of hydrogen passivation of impurities and defects to better control processes for high-efficiency c-Si modules. Researchers at Sandia continue to investigate plasma texturization of multi-crystalline cells.

• Research and Development of the Balance-of-System
  Research within the industry and the national laboratories has explored improved solid-state switching methodologies for inverters, new balance-of-system hardware designs, and entire PV systems that are cost effective. Some significant improvements in balance-of-system components developed in 2000 included new utility-interactive, stand-alone and micro-inverters that are listed for safety and code compliant for installation. Other inverter improvements include higher efficiency, reduced operating losses, lowered cost, improved quality control, and smaller size. Issues pertaining to environment, safety and health remained an essential aspect of working with the balance-of-system industry and were included in all work sponsored by the National PV Program.

• Research on High Performance and Concentrating PV
  The National PV Program plan contains a 10-year program goal to double the efficiency of multi-junction thin-film modules. There is also a goal to demonstrate a high-efficiency III-V cell in a pre-commercial concentrator module. To help achieve this objective, the High Performance PV Initiative was begun in 2000. The NCPV and Spectrolab are collaborating toward a goal of a 40% cell under concentrated sunlight. ENTECH Corporation produced a 28% efficient mini-module using a triple-junction, high-performance solar cell. Work continues on several fronts to develop materials that will perform well at very high concentrations of sunlight.

Manufacturing and Implementation

• Industry Roadmap
  Success of the National PV Program depends on the direction, resources, best scientific and technological approaches, use of the best technologies and continued efforts of the best and brightest among industry, federal laboratory and university partners. The National PV Program worked in concert with the industry to finalize the draft of an "Industry Roadmap" to support work that focused on the roadmap's vision and strategies to provide competitive PV products and services.

• Photovoltaic Manufacturing
  A major goal of the PV manufacturing project has been to help the U.S. PV industry improve manufacturing processes and equipment; accelerate manufacturing cost reductions for modules, balance-of-system components, and integrated systems; and enhance the investment opportunities for substantial scale-ups of U.S.-based manufacturing capacities. The PVMaT program transitioned existing and prototype production into advanced and improved manufacturing technology and processing for the industry through R&D.
  PVMaT was a major undertaking for the PV industry as well as for the U.S. Department of Energy. Approximately USD 90M in contract money has been invested through 2000 where the industry provided another USD 70 M (more than 43,3% of the total) as cost share. PVMaT began with a problem identification phase. It then progressed to improvement of processes, reduction of costs, and improvement of performance of PV modules. Solving generic manufacturing problems was a specialized effort. PVMaT then addressed areas of R&D related to cost-effective PV end-products, including module manufacturing, flexible manufacturing approaches, system integration, and balance-of-system. The latest partnerships in PVMaT include 14 cost-shared contracts placed with industrial partners in 1998. They were two- and three-year contracts for PV system and component technology and PV module manufacturing technology and some continued into 2000. New manufacturing facilities, production lines, and processes will take advantage of the improvements resulting from the PVMaT cost-shared work. Manufacturing and performance of systems and components were also advanced with PVMaT.
  A new solicitation for letters of interest in performing PV manufacturing R&D was released in August 2000. The solicitation was entitled "PV Manufacturing R&D - In-line Diagnostics and Intelligent Processing in Scale-up Manufacturing." It solicited interest from individual or teamed U.S. PV and related industries in addressing topics related to manufacturing PV modules, components and systems. The primary focus is to address approaches for intelligent processing and larger-scale manufacturing as identified in the PV Industry Roadmap. The solicitation is intended to be a first step toward more accelerated growth in the capability of the U.S. industry to produce cost-effective products.

• Systems Research and Development
  A systems engineering program that included a balance-of-system program continued this year with Sandia leading efforts to fund evolutionary changes to power processing hardware resulting in improved reliability and performance. The reliability of switchgear, ground-fault detection and interruption equipment, and component safety certification programs were also funded. Sandia continued working with industry in 2000 to improve "Total Quality Management" programs in the manufacturing and assembly areas. Sandia also assisted industry in "Highly Accelerated Life Tests (HALT™)" and "Highly Accelerated Stress Screens (HASS™)" to improve quality and reliability of hardware. The U.S. Department of Energy's PV Program test facilities at Sandia and NREL continue to contribute significantly to all of the programs.

Market Development

The National PV Program provided continuing support for state-supported PV applications using assistance through the Interstate Renewable Energy Council. Much of this work provided PV applications and education for parks and public spaces through the Photovoltaics for Utilities (PV4U) program. This approach to removing barriers to PV for utilities is a network of 15 state working groups that promote PV. For example, the PV4U consumer project works to educate and assist state-appointed consumer representatives about PV issues. Installation, metering, and utility interconnection of small-scale PV systems remains a high priority for this group.

Successful advances from the PV Building Opportunities in the U.S. (PV:BONUS) program to assist U.S. industry in exploring the potential market for building-integrated PV were used in 2000. PV on buildings or integrated into buildings to replace windows, skylights and walls, while generating electricity, were installed in 2000. No major national demonstration programs were active during 2000. Study programs were sponsored by various sectors of the PV program, state governments and utilities, but most of those programs were implemented because the target PV system was cost effective or because the sponsor was developing PV applications or training programs. Deregulation of the electric utilities has spurred several state programs that require installation of PV energy systems.
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Electrical and Personel Safety through Codes and Standards

The IEEE Standards Coordinating Committee (SCC21) made excellent progress in publishing a utility interconnect guideline for PV systems.The new IEEE929-2000 standard was published in January. NREL headed up the IEEE PV standards activities and also actively participated in the International Electrotechnical Commission activities for PV-related international standards. Underwriters Laboratories finalized the UL1741 "Standard for Static Inverters and Charge Controllers for Use in Photovoltaic Power Systems" and is now considering expansion of the standard to include inverters for all distributed generation. Coordination with the NEC and IEEE interconnect guidelines was essential for finalizing the UL1741 standard.

PowerMark Corporation continued as a non-profit certification body. PowerMark previously recognized the Arizona State University PV Testing Laboratory (PTL) and approved them for performing module certification tests based on the accreditation certificate they received from the American Association of Laboratory Accreditation. Module models have been qualified to IEEE1262/IEC1215 or IEEE1262/IEC1646 qualification standards since the work began in 1996. Additionally, the PTL has tested many module types to the UL1703 PV module standard to determine their suitability for listing and now has a reciprocity arrangement with European testing organizations.
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Market Development Incentives

Other National PV Program pilot projects and cooperative programs are underway in Africa, China, India, and Russia. Additional work through Winrock International, NREL, Sandia, and non-governmental agencies provides collaborative PV efforts in other countries such as Brazil, China, Central America, Ghana, Indonesia, Kenya, Philippines, the Dominican Republic, Russia, South Africa, and Venezuela.
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Future Outlook

The Million Solar Roofs Initiative promotes the use of solar thermal and PV to reduce the energy demands of buildings. It enables businesses and communities to install solar systems on one million rooftops across the United States by 2010. The U.S. Department of Energy leads this initiative by working with partners in the building industry, local governments, state agencies, the solar industry, electric service providers, and non-governmental organizations to remove market barriers and strengthen grassroots demand for solar technologies. In 2000, the Department of Energy had fifty partners that had made commitments for one million solar roofs by the year 2010. The Florida Energy Office, the Florida Department of Community Affairs and the U.S. Department of Energy through Sandia, the PV industry, the Florida Solar Energy Center and nine end-user groups have committed to contributing 20 000 of the nations million solar roofs. Photovoltaic systems installed in 2000 included 750 different systems amounting to approximately 3 MW peak rating.
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Further reading about the USA

• USA - Country information