CAISO renewables set all-time record 97.6% with more records possible in April: operator

The California Independent System Operator set an all-time peak record when renewables provided 97.6% of the grid's electricity on April 3, with the potential for more renewable records in April, according to the grid operator.

The record was reached briefly at 3:39 pm PT April 3, surpassing the previous record from March 27 by 1.2 percentage points, CAISO announced April 14. The grid also set a historical solar peak of 13.628 GW just after noon April 8, surpassing a March 24 record by 1.3%, and an all-time wind peak of 6.265 GW just before 3pm March 4, surpassing a February record by 1.4%.

"When we see renewable energy peaks like this, we are getting to re-imagine what the grid will look like for generations to come," Ashutosh Bhagwat, chair of the ISO Board of Governors, said in the April 14 statement. "These moments help crystallize the vision of the modern, efficient and sustainable grid of the future."

The ISO has been integrating increasing amounts of clean power onto the grid to help reach the state's clean energy goal of carbon-free power by 2045.

"This new record is testament to the hard work and collaboration of many people, from policymakers to system operators," CAISO President and CEO Elliot Mainzer said in the April 14 statement. "While these all-time highs are for a brief time, they solidly demonstrate the advances being made to reliably achieve California's clean energy goals."

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

CAISO leads the US in utility-scale solar capacity at 14.628 GW, an increase of 9% year on year, according to the American Clean Power Association's quarterly report for Q4 2021. The ISO also ranks sixth for utility-scale wind at 6.142 GW, up 5% year on year, and was second overall for combined utility-scale wind, solar and battery storage capacity with a total of 22.929 GW for Q4 2021, a jump of 13% year on year due to a focus on battery storage additions.

Renewable additions

CAISO has collaborated with the California Public Utilities Commission, the California Energy Commission and a broad group of stakeholders on market and transmission improvements to integrate increasing amounts of renewable energy, according to the statement.

The grid operator has about 15 GW of grid-connected solar power capacity and almost 8 GW of wind online, with another 600 MW of solar and 200 MW of wind slated to be added by June 1.

In addition, the operator currently has more than 2.7 GW of storage, most of it in lithium-ion batteries, which is expected to grow to about 4 GW by June 1.

"Storage has been critical to reliability during the transition to renewable energy, as it charges using solar and wind output during the middle of the day, and reinjects it back onto the grid on hot summer evenings when solar production has ended and demand remains high," according to CAISO.