Solar power in California

Solar power has been growing rapidly in the U.S. state of California because of high insolation, community support, declining solar costs, and a renewable portfolio standard which requires that 60% of California's electricity come from renewable resources by 2030, with 100% by 2045. Much of this is expected to come from solar power via photovoltaic facilities or concentrated solar power facilities.

At the end of 2023, California had a total of 46,874 MW of solar capacity installed, enough to power 13.9 million homes in the state. California ranked as the highest solar power generating state in the nation, with solar power providing for 28% of the state's electricity generation. The Solar Energy Industries Association predicts that California will increase its solar capacity by over 20,000 MW over the next five years, the second highest increase in solar capacity in the country behind Texas at 41,000 MW.

The state government has created various programs to incentivize and subsidize solar installations, including an exemption from property tax, cash incentives, net metering, streamlined permitting for residential solar, and, in 2020, requiring all new homes have solar panels.

Over the last 20 years, California has been home to a number of the world's largest solar facilities, many of which are located in the Mojave Desert. In 1991, the 354 MW Solar Energy Generating Systems plant (located in San Bernardino County, California) held the title until being bested by the 392 MW Ivanpah Solar Electric Generating System, a solar thermal plant located in San Bernardino County near the Nevada border.

The early to mid 2010s saw the sharpest increase in solar development. By the end of 2013, California had 490 MW of concentrated solar power and 5,183 MW of photovoltaics capacity in operation.

In 2014, the 550 MW Topaz Solar Farm became the new "world's largest operational" solar facility and went online in San Luis Obispo County, California. A second 550 MW facility, Desert Sunlight Solar Farm, went online in Riverside County in 2014, constructed by First Solar. In June 2015, the 579 MW Solar Star facility went online, becoming the new largest operational solar facility and making California host to the three largest photovoltaic solar facilities in the world. There are several proposals for even larger facilities seeking regulatory approval in California, such as the 2.7 GW Westlands Solar Park.

In 2014, California led the nation in the number of homes which have solar panels installed, totaling over 230,000. Many were installed because of the Million Solar Roof Initiative.

In December 2017, the Solar on Multifamily Affordable Housing (SOMAH) program was approved by the California Public Utilities Commission. The program plans to allocate one billion dollars from the state's greenhouse gas cap-and-trade program to incentivize owners of affordable, multi-family buildings to install solar, with a goal of adding 300 MW of capacity by 2030.