CAISO said Thursday it set a record for renewables on its grid earlier this month when nearly all the ISO’s electricity came briefly from clean, renewable resources.

The peak of 97.6% happened at 3:39 p.m. PT on April 3 and broke the previous record of 96.4% set a week earlier on March 27. Even higher numbers are possible this month, the ISO said.

CAISO has been adding more renewable energy to its grid in support of the state’s goal of achieving 100% clean power for retail customers by 2045.  

“When we see renewable energy peaks like this, we are getting to re-imagine what the grid will look like for generations to come,” CAISO Board of Governors Chair Ashutosh Bhagwat said in a news release. “These moments help crystallize the vision of the modern, efficient and sustainable grid of the future.”

CAISO’s installed renewable energy mix consists of about 57% solar, 30% wind and smaller amounts of geothermal energy, small-hydro resources and biofuels. About 32% of California’s energy mix came from renewable power in 2020, the most recent year for which figures are available, according to the state Energy Commission.

The ISO also set a new solar peak of 13.6 GW early in the afternoon of April 8 and an all-time wind peak of 6.2 GW shortly before 3 p.m. March 4.

“Renewable peaks typically occur in the spring due to mild temperatures and the sun angle allowing for an extended window of strong solar production,” the news release said. “ISO analysis forecasts a potential for more renewable records in April.”

SPP reached a similar milestone last month when it became the first multistate grid operator to temporarily serve more than 90% of its demand with renewable energy. (See SPP Stuns with 90.2% Renewable Penetration Mark.)

SPP’s footprint includes high-wind regions of the Dakotas, Kansas, Missouri, Nebraska, Oklahoma and Texas, and its resource mix includes about 31 GW of installed wind capacity.