Our recent columns have focused on federal energy legislation and the meager resources allotted to renewable energy in contrast to traditional energy sources. Federal government funding has been significant in the development of renewable energy sources. Private interests are often unable or unwilling to take the risk involved in the developing new energy sources since they operate on very short time horizons and find it difficult to justify the long-term investments necessary to develop a new technology.
The initial demand for solar cells came from government sponsored efforts to explore space. While solar cells proved their worth in space, it would take years of research and development to establish terrestrial applications for them and find niche markets to grow the industry.
For the past 25 years, the world PV market has grown at an average compounded rate of 20 percent per year. Silicon-based crystalline and polycrystalline solar cells dominate the world market.
Paul Maycock, editor of Photovoltaic News, expects crystalline solar cells to continue to play a dominant role in the marketplace due to increasing efficiency, declining manufacturing costs and their proven 30-year reliability.
Maycock also supports ongoing efforts to develop thin-film solar cells since they hold considerable promise for even lower cost manufacturing. According to Maycock, crystalline silicon modules cost from $2.70 to $2.90 per watt to manufacture while amorphous silicon cells cost $2.25.
Amorphous solar cells are only one form of thin-film technologies, and with low efficiencies appear best suited to large spaces such as rooftops of commercial buildings and residences.
Many of the improvements in cell efficiencies, panel performance and manufacturing are attributable to the research and development program coordinated by the National Renewable Energy Lab in Golden, Colo. The program has had three major themes since it was redesigned following cutbacks during the Reagan administration. One is to understand and increase the efficiency of solar cells. Second is to emphasize research on thin-film solar cells, including amorphous, copper indium, cadmium telluride and very high III-V stacked concentrator cells. The third theme covers research on the manufacturing process for solar cells.
A recent review of the program indicates that equipment and facilities are aging and failing at national laboratories and cooperating universities. Funds for personnel and equipment have been redirected to maintain equipment in need of replacement. Experienced personnel are migrating to other programs and the first wave of retiring personnel are in need of timely replacements to sustain the programs.
Since Japan and Germany have replaced the United States as leading world manufacturers of solar cells, sustaining government-sponsored research is important to address the growing competition for future PV markets.
Developing thin-film photovoltaics remains important. Their potential for low material costs, large-scale low cost production, flexibility and low weight give them significant advantages for building integrated applications of solar cells.
It has taken 50 years of research and development for PV technologies to reach the point where they are ready to become a significant source of electricity. Progress would have been much faster if federal funding for research and development had been more robust and continuously available at predictable levels.
Japan has captured the lions share of the worlds PV market by setting ambitious goals and providing sufficient public funding to meet those goals in a timely manner. We created the PV marketplace nearly 50 years ago, and still have the talent and research potential to be a significant player in ever expanding global markets.
While the pending federal energy bill has some funding for renewable research and development, it pales in comparison to what is being invested in coal and nuclear power. It is not a strong commitment to a sustainable energy system.
Reference: Solar Today, Vol. 18, No. 1 (January/February, 2004).