California’s Solar Equipment List Saves Time and Money

California’s commitment to solar energy development has created a large market for solar energy technologies of all sizes. In Senate Bill 1 (SB 1), enacted in 2006, the state legislature directed the California Energy Commission to establish criteria for which PV equipment would be eligible for rebates under the state’s solar electric incentive programs, along with conditions for those incentives and rating standards for solar incentive programs. Today the commission’s list ( includes information on thousands of models of PV modules, inverters, and other solar equipment, far more than other databases. The National Renewable Energy Laboratory (NREL) calls it “the most robust source of [performance and safety] information for PV equipment in the United States,” and “the de facto national eligible equipment list.”

Ensuring High Quality and Performance

SB 1 provided California state energy agencies with $3.3 billion over 10 years to support 3,000 megawatts of solar projects. To support this goal, the bill laid out specific expectations that projects had to meet in order to qualify for ratepayer-funded incentives, including the following:

  • High-quality solar energy systems with maximum performance to promote the highest energy production per ratepayer dollar
  • Optimal system performance during periods of peak demand.

In December 2007, the California Energy Commission established eligibility criteria, conditions for incentives, and ratings standards. All major components of solar energy systems (PV modules, inverters, and meters) had to be chosen from eligible equipment lists. To have their equipment included on the lists, manufacturers had to provide certification from a nationally recognized testing laboratory that the components met safety standards in the National Electrical Code. They also had to have the components tested once by an accredited test laboratory to verify performance in the field. The Energy Commission verified information provided by manufacturers.

Less than a decade later, numerous organizations are using the California list for diverse purposes. Fifteen states in addition to California that have solar PV incentive programs refer to the approved equipment list to calculate upfront incentives, project future costs for performance-based incentives, and/or determine whether the PV equipment is eligible for tax credits. Together with California, these states represent 70 percent of the U.S. solar market.

Other stakeholders that use the list include utilities, building designers and engineers, and project developers. Two federally funded solar PV performance models—NREL’s System Advisor Model (SAM) and Clean Power Research’s PowerClerk software—estimate the expected performance of specific PV systems in designated locations based on underlying data from the California list. These tools are used by software developers, utilities, and energy agencies nationwide. The California Energy Commission provides the data free of charge.


This blog post written by Jenny Weeks and Warren Leon, and was originally published in the Clean Energy States Alliance (CESA)’s 2015 report “Clean Energy Champions: The Importance of State Policies and Programs.” This report provides the first-ever comprehensive look at the ways states are advancing clean energy and suggests how to further encourage clean energy growth. For more information about CESA, please visit

See also: “Transitioning the California Energy Commission Eligible Equipment List to a National Platform” by the National Renewable Energy Laboratory (NREL), October 2013.

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Warren Leon is Executive Director of the Clean Energy States Alliance. He oversees the organization’s day-to-day operations and leads strategy development. He has written and edited many reports for CESA, including serving as lead author for  Returning Champions: State Clean Energy Leadership Since 2015  and  Solar with Justice: Strategies for Powering Up Under-Resourced Communities and Growing an Inclusive Solar Market . Prior to working for CESA, Warren was Director of the Massachusetts Renewable Energy Trust, Executive Director of the Northeast Sustainable Energy Association, and Deputy Director for Programs at the Union of Concerned Scientists. He co-authored the influential book  The Consumer's Guide to Effective Environmental Choices . He holds a Ph.D. from Harvard University.

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