Driving the future

No place like California

The state produces more renewable energy than any other in the US

For about an hour on April 30th, grid operators at the California Independent System Operator (ISO), which serves about 80% of the state, had enough electricity from renewables (solar, wind, geothermal and small hydropower) to meet all of the demand in their area.

The State of California produces more renewable energy than any other US state. Much of the renewable power came from vast solar farms, located in the southern area of Los Angeles. Solar power makes up the majority of California’s renewables (helped along by its near year-round sunshine), followed by wind energy then to a lesser extent, geothermal, biomass, biogas and small hydro.

Governor Gavin Newsom’s budget proposal for next year includes around $2bn to boost the transition to green energy. California has set a goal of achieving 100% clean electricity by 2045, and President Joe Biden’s has pledged to decarbonize the US power grid by 2035.

California produces more renewable energy than any other in the US, much of it came from vast solar farms, located in the southern area of Los Angeles.

The record of last month shows all the progress California has made in the last decades. Since 2005 the share of energy from renewable sources has tripled. In 2019, over 60% came from renewable and zero-carbon sources, such as hydro and nuclear. Some 59% of the state’s electricity came from renewable and zero-carbon sources in 2020, according to the latest data from the California Energy Commission. 

Still, at the time the record fell, natural gas power plants were generating about 10% of the electricity on the California ISO’s grid.


In the Mojave Desert on the California-Nevada border, the Ivanpah Solar Electric Generating System uses 347,000 mirrors the size of garage doors to heat the water that feeds the steam generators. This solar thermal plant helps produce 10 per cent of the state's electricity. | Mark Boster / Los Angeles Times

As already explained, one of the major problems of renewables is their dependency on climate change: a solar farm can produce energy only during the day while a wind farm works only if there is wind. If these conditions don’t exist, both energy sources can’t ensure constant energy supply to meet the demand.

To face that, California is working on batteries to store extra renewable energy generated during the day so it’s available also at night. “The more storage that we can get online that can be charged by solar, the better our chances are of making sure that when the state needs power the most, it’s the cleanest it can be,” says Shannon Eddy, executive director of the Large-Scale Solar Association.


Renewables do not guarantee continuous supply. To address this problem, California is implementing batteries that can store the energy produced during daylight hours so that it can also be used at night.

Still, batteries only make up a small fraction of the power that’s needed when the sun goes down. Studies looking at how California can get to 100% carbon-free electricity by 2045 find that natural gas will continue to play a role for several decades

Gas has stuck around because it’s affordable and offers reliability to the grid. That is why California keeps almost 40 GW of gas in service to prevent energy shortfalls, especially on hot summer days. Gas also provides reliability services in local areas of the grid where it’s difficult (but possible) to replace it with local clean energy resources.


In western Kern County, solar panels occupy nearly two square miles of land forming the Beacon Solar Project, owned by the Los Angeles Department of Water and Power. | Mel Melcon/Los Angels Times

Adding to the challenge of retiring gas, California is shutting down its last nuclear plant — the Diablo Canyon nuclear facility, which is scheduled to shut down by 2025, and hydro is becoming less reliable due to drought. 

To line up replacements for these sources, in February of this year, the California Public Utilities Commission approved a long-range energy plan that would require nearly 24 GW of new renewables and more than 12 GW of new batteries by 2032. If California wants to hasten the transition from gas, it should procure even more capacity from diverse sources like geothermal and offshore wind.

According to Canary Media, California will also need to continue relying on its neighbours, the other Western states, which also have many clean energy resources. Both in Arizona and in Idaho the largest utilities have announced voluntary goals to reach 100% clean power. 

1st June 2022