By Malinda Geisler, content specialist, AgMRC, Iowa State University, malindag@iastate.edu.
Profile revised May 2008.
Overview
Solar energy is a clean, renewable energy that may be used to supplement or replace existing power sources. Solar energy has many applications; a few include helping to reduce the reliance on overhead, electrical light sources; to heat water; or generate power to operate remote equipment.
The “solar cell” or photovoltaic (PV) cell technology was discovered in 1954 by Bell Telephone researchers. Just a few years later, PVs were already being used to power U.S. space satellites. The success of PVs in space created opportunities for commercial applications that continue to grow 50 years later.
Sales and Market Share
Even with successful applications in the space program, the solar industry did not experience rapid growth until the oil embargos of 1973 and 1979. With support from Federal and state tax incentives, the solar industry grew slowly over the next 10 years. Through consolidation of companies and restructuring of tax credit programs, the number of firms has decreased since 1990, yet the growth rate of solar collector equipment sales continues to grow.
Domestic shipments of solar thermal collectors were 19.5 million square feet (sq. ft.) in 2006. Total revenue for systems shipped in 2006 was $31.3 million. The residential market is the primary market for solar thermal collectors, accounting for 15.1 million sq. ft. of solar thermal collectors and 73 percent of total shipments, with swimming pool heating being the most common application. Installation of solar PV devices in the United States rose 33 percent in 2006 over 2005. The United States installed about 140 MW in 2006. Electricity generation is the most common end use for PV cells and modules. The average unit price of PV cells was $2.03 per peak watt in 2006. Module prices averaged $3.50 per watt in 2006.
Usage and Demand
In 2006, total U.S. net generation of all electricity was more than 4,065 billion kilowatts. Coal generated nearly 49 percent, nuclear generated 19.4 percent and natural gas accounted for 20 percent. Hydroelectric accounted for 7 percent and petroleum was 1.6 percent. Solar and wind combined totaled about 2.4 percent of the net electrical generation.
Sources
Electric Power Annual, Energy Information Administration, 2007.
Energy: Supply and Demand, People and the planet.net.
Solar Thermal and Photovoltaic Collector Manufacturing Activities 2006, Energy Information Administration, 2007.
Up with the Sun: Solar Energy and Agriculture, Union of Concerned Scientists, 1996.
World PV Industry Report Highlights, Marketbuzz, 2007.