For consumers or organizations wishing to install on-site renewable energy systems, there are a variety of options available, including electricity generating systems and thermal systems that can displace electricity or fossil fuel use.
- Solar photovoltaics convert sunlight directly into electricity.
- Solar hot water systems use the sun's energy to heat water.
- Wind turbines convert the kinetic energy in wind into mechanical power that runs a generator to produce electricity.
- Geothermal heat pumps use the constant temperature of the upper 10 feet of the Earth to heat and cool buildings.
- Fuel cells produce electricity from hydrogen and oxygen and can be powered by a number of sources, including renewables.
- Biomass power systems use biomass feedstocks such as wood waste or methane from animal waste or other sources to generate electricity. Biomass resources can also be used in direct heat and combined heat and power applications.
- For general information about distributed generation systems, see Distributed Generation (Wikipedia).
There has been increased deployment of on-site renewable systems in recent years, by both residential and non-residential energy consumers. The increased availability of tax incentives, credits, and grants for renewable energy, as well as financing mechanisms, such as the residential power purchase agreement and leasing options for solar, have contributed to the growth in on-site renewable generation.
- In 2011, U.S. grid-connected PV capacity doubled from 2010. Cumulative installations increased to 4 GWDC, with 1,845 MWDC installed in 2011 alone. (Sherwood 2012 )
- Cumulative small-wind capacity (defined as turbines with capacity of 100 kilowatts or less) in the U.S. surpassed 200 MW in 2011. In 2011 alone, 22.7 megawatts of new small-wind capacity were installed in the U.S.
One issue for both residential and non-residential consumers to consider when installing an on-site system is who will own the associated renewable energy credits (RECs). RECs represent the environmental attributes of the power produced from renewable energy projects and are sold separate from commodity electricity. Owning RECs from a project allows consumers to make claims that they are supporting renewable energy. However, many on-site systems may choose to take advantage of the financial benefit of selling RECs, in order to make the project financially attractive. RECs may also be sold to a local utility in order to obtain an upfront incentive payment. The Federal Trade Commission (FTC) provides guidance to marketers to help them avoid making claims that are unfair or deceptive. See the FTC's Green Guides for more information.
Examples of Organizations with On-site Renewable Energy Systems
Below is a selected list of federal and state agencies, cities, universities, and businesses that have installed on-site renewable energy systems. You can find descriptions of green power generation by these organizations by following the links below. For additional information on organizations purchasing green power or installing on-site renewable energy systems, see the U.S. EPA Green Power Partnership.
American Wind Energy Association (AWEA). (2010). AWEA Small Wind Turbine Global Market Survey, Year Ending 2009. Washington, DC: American Wind Energy Association.
Coughlin, J.; Cory, K. (2009). Solar Photovoltaic Financing: Residential Sector Deployment. 66 pp.; NREL Report No. TP-6A2-44853.
NREL (2009). Solar Leasing for Residential Photovoltaic Systems. NREL/FS-6A2-43572.
Department of Energy (2010). Homeowners Guide to Financing a Grid-Connected Solar Electric System. 4 pp.; DOE/GO-102010-3129.
Department of Energy (2010). Selecting and Installing a Geothermal Heat Pump System.
Department of Energy (2010). Solar Water Heaters.
Department of Energy (2007). Small Wind Electric Systems: A U.S. Consumer's Guide.
Sherwood, L. (2012). U.S. Solar Market Trends 2011. Interstate Renewable Energy Council. August.