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Solar Power Profile

By Malinda Geisler, content specialist, AgMRC, Iowa State University, malindag@iastate.edu.
Profile revised June 2012.


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 heating water, generating power to operate remote equipment and helping to reduce the reliance on overhead, electrical light sources.
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.

Solar thermal collectors are divided into low-, medium- and high-temperature collectors. Low-temperature collectors that collect less than 110 degrees Fahrenheit are used to heat swimming pools and low-grade water and space heaters. Medium-temperature collectors (greater than 110 degrees F, generally 140 to 180 degrees F) are mainly used for hot water heating. High-temperature collectors (180 degrees F or higher) are used primarily by utilities and independent producers to generate electricity for a grid. Total revenue of all solar thermal collector shipments was $96.7 million in 2009, up from $81.3 million in 2008, according to the most recent U.S. government report.

Domestic shipments of solar thermal collectors were 12.2 million square feet (sq. ft.) in 2009. The residential market is the primary market for solar thermal collectors, accounting for 10.2 million sq. ft. of solar thermal collectors and 84 percent of total shipments, with swimming pool heating being the most common application.

Usage and Demand

In 2011, total U.S. net generation of all electricity was more than 4 trillion kilowatthours. Coal generated 42 percent, nuclear generated 19 percent and natural gas accounted for 25 percent. Petroleum was less than 1.0 percent. Other renewables, including hydro, accounted for 13 percent. Solar energy accounted for 1 percent of the renewable energy. 

H.R. 1424 passed into law on Oct. 3, 2008. It was an eight-year extension of the 30 percent solar tax credit. It removed a monetary cap for residential solar electric installations.


American Solar Energy Society

Electricity Explained, Energy Information Administration.

Solar Thermal Collector Manufacturing Activities, Energy Information Administration.

Links checked August 2013.


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