Community solar farm
A community solar farm or solar garden is a solar power installation that accepts capital from and provides credit for the output and tax benefits to individual and other investors. The power output of the farm is credited to the investors in proportion to their investment, with adjustments to reflect ongoing changes in capacity, technology, costs, and electricity rates. Companies, cooperatives, governments or non-profits operate the farms.
Centralizing the location of solar systems has advantages over residential installation that include:
- Trees, roof size and/or configuration, adjacent buildings, the immediate microclimate and/or other factors which may reduce power output.
- Building codes, zoning restrictions, homeowner association rules and aesthetic concerns.
- Lack of skills and commitment to install and maintain solar systems.
- Expanding participation to include renters and others who are not residential property owners.
The Solar Gardens Institute maintains a national directory of community solar projects and organizations. As of 2011 farms encompassed both photovoltaic and concentrating solar power technologies.
 United States
Federal and other tax policies are necessary to finance community solar farms. U.S. Senator Mark Udall introduced the SUN Act (Solar Uniting Neighborhoods) to extend the existing 30% tax credit to community solar farms in 2010 and 2011.
The bill would enable groups of individuals or homeowner associations to develop utility-scale solar power facilities in collaboration with local utilities that would distribute the power and credit owners based on their percentage of investment in the solar farm, extending the tax credits accordingly.
“These projects have the potential to drastically increase the adoption of clean energy nationwide, but the tax code hasn’t kept up,” Udall said. “You can get a 30-percent tax credit for putting a solar panel on your house, but not for investing in a solar farm.”
SolarShares (2007) offers customers of the Sacramento Municipal Utility District the opportunity to buy "shares" in its solar farm. The electricity generated by each customer’s “shares” appears as a credit on his or her energy bill, a savings expected to average between $4–$50 a month, given sunshine variability. For a monthly fee—starting at $10.75 a month (averaging 9%) for a 0.5 kW system—participants opt into solar power production. The current phase is sold out, although plans are in progress to expand capacity.
The PVUSA array in Davis, California (2001) provides virtual net metering for city-owned meters. The California legislature passed a law specifically allowing this for this individual array. A bill expanding solar gardens to the whole state (SB843) died in 2011.
In the Colorado state House, Rep. Claire Levy, D-Boulder, introduced a bill that requires the Public Utilities Commission to rewrite rules to direct investor-owned utilities to offer rebates for community solar gardens. Governor Bill Ritter signed the bill on June 5, 2010.
HB10-1342, the Community Solar Gardens Act specified:
- Energy must be sold directly to an investor-owned utility.
- Utility pays retail + REC’s.
- Utility provides Virtual Net Metering credit on the subscribing customer’s bill.
- System size limited to 2 megawatts (MW).
- 6 MW total limit on the program for first three years.
- There must be at least 10 subscribers.
- Subscribers must be located in same county or city as the solar garden. Subscribers whose county has a population less than 20,000 may subscribe in a neighboring county.
- Subscribers may buy up to 120% of their own power use worth of solar power.
- Either a for-profit or nonprofit entity may own and administer the solar garden.
State Representative Matt Patrick authored the Green Communities Act of 2008, authorizing what was formally known as “neighborhood net-metering”, which allowed a group of residents in a neighborhood/town to pool resources to cover the capital cost of a renewable energy installation.
Residents of Falmouth constructed a cooperatively run solar garden. Each member was to receive benefits from the co-op; including tax credits, S-RECs, and the output purchased by NSTAR for its residents. Known as the Brewster Community Solar Garden, it is a 345.6 kW community solar farm located on Cape Cod.
Massachusetts and the Federal government each offered incentives to improve solar economics. A traditional investment in photovoltaics without incentives would take 12 or more years to pay back the initial cost. The incentives lowered the payback period to 6–10 years.
Electric utilities in St. George built a large photovoltaic facility to exploit 310 days a year with sunlight, and allowed residents to purchase it to supplement conventional energy. The program required no set-up or maintenance for the participant.
Participation is sold in whole and half units of 1 kilowatt (“kW”). A 1 kW “unit” on the SunSmart grid cost $6,000. One unit equals approximately 15% of the average home’s monthly power (or about 140 kWh). A one-time tax credit of 25% of the purchase price, up to a maximum of $2,000, was available from the state of Utah. Purchasers received a monthly energy credit for the energy produced that month by the “unit” of panels.
 United Kingdom
 See also
- Galbraith, Kate (March 15, 2010). "For Renters, Solar Comes in Shares". New York Times.
- "Residential Solar Energy Installation - 13 FAQs And The Answers". Retrieved April 16, 2010.
- Taylor, E. (November 3, 2009). "Photovoltaics: Getting Started". PVPower. Retrieved April 16, 2010.
- Rubin, Evelyn (September 5, 2006). "Everything You Wanted To Know About Solar Power and Were Afraid To Ask". Seeking Alpha. Retrieved April 16, 2010.
- Solar Gardens Community Power
- Community Energy Directory
- "S. 3137, The Solar Uniting Neighborhoods (SUN) Act of 2010". Washington Watch. Retrieved April 15, 2010.
- Williams, David O. (March 18, 2010). "Udall’s SUN Act would extend tax credits to community ’solar farms’". The Colorado Independent. Retrieved April 2010.
- "Solar Shares". Sacramento Municipal Utility District. Retrieved May, 2010.
- Zheng, Connie (March 16, 2010). "Sacramento Offers Solar Shares for Renters". Retrieved April 15, 2010.
- Bill Number SB 843
- "SB843". California State Senate. June, 2011. Retrieved December 2011.
- Final Text of Community Solar Act
- "Falmouth Community Solar Garden". Retrieved April 15, 2010.
- Real time data
- "Tomorrow's Power today". SunSmart. Retrieved April 15, 2010.
- The Solar Park
- "Solar Uniting Neighborhoods legislation". US Senate. June 17, 2011. Retrieved December 2011.
- Sewall, Adam (March 17, 2010). "Solar Power Rundown for Wednesday, March 17". Retrieved April 15, 2010.