Farmers are experts are tapping solar power for food and can also use solar energy many ways for energy independence. REAP funds a range of both solar thermal and solar electric projects.
Solar thermal technologies harness the sun’s energy to create hot water and hot air for on-farm and business use. They can use air or water to transfer the heat to its destination. REAP also funds high-temperature collectors that concentrate sunlight using mirrors or lenses and are used to generate electric power by transforming water into steam, which runs a turbine and electric generator.
USDA’s program rules separate solar thermal into large and small systems. Large systems are those for which the rated storage volume is greater than 240 gallons or have a collector area of more than 1,000 square feet. Small systems are all other systems.
Solar electric systems use the sun’s energy to directly generate electricity through photovoltaic panels. As with solar thermal systems, USDA’s program rules distinguish between large solar electric systems — which are larger than 10 kilowatts (kw) rated power — and small solar electric systems, which are 10 kw and smaller. Either system can be stand-alone (such as one that powers an irrigation pump) or connected to the electric grid (often occurs when the panels provide power for buildings and other centralized operations).