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California Energy Leaders Report Progress on Grid Reliability Ahead of Summer 2025

For Immediate Release: May 2, 2025

SACRAMENTO — After a series of climate-driven challenges between 2020 and 2022, California energy leaders are encouraged by recent progress and believe the state is better positioned to meet demand this summer, while remaining vigilant about ongoing risks.

The outlook was presented during today’s annual Summer Energy Reliability Workshop, where officials from the California Energy Commission (CEC), California Public Utilities Commission (CPUC), California Independent System Operator (California ISO), other state agencies and partners in the energy and utilities industry convened to assess readiness for the summer and strategies to manage extreme weather and potential grid challenges.

Thanks to rapid clean energy deployment, expansion of battery storage, and strategic efforts to build up emergency reserves, California heads into summer with more resources to meet electricity demand, including the extreme heat conditions experienced in recent years. Still, officials remain vigilant as the accelerating impacts of climate change contribute to more frequent and severe weather extremes.

“California’s grid is stronger, smarter, and cleaner than it has ever been,” said CEC Vice Chair Siva Gunda. “We’ve invested in the tools and resources needed to manage extreme weather and maintain reliability as we continue our transition to 100 percent clean energy.”

The state has taken aggressive action over the past five years to confront grid reliability challenges exposed by climate change. 

Today, California is better prepared:

• More than 20,000 megawatts (MW) of new clean energy supply have been added since 2021.
• Battery storage capacity statewide, including residential, commercial, and utility-scale installations, has surged past 13,000 MW, up from about 700 MW heading into 2020. This allows for solar and wind energy captured during the day to power homes and businesses in the critical evening hours.
• The Strategic Reliability Reserve, established by legislation after challenges in 2020 and 2021, now provides 4,000 MW of backup resources, including cleaner options like demand response programs and virtual power plants.
• The extension of operations at the Diablo Canyon Power Plant provides additional capacity during the clean energy transition, providing stability while new renewable resources and storage continue to come online.
• State energy agencies have improved forecasting, coordination, and operational strategies to better manage complex situations.
• Coordination with regional partners across the west, including the Western Energy Imbalance Market, continue to enhance grid reliability.

“Through historic clean energy investments, strategic planning, and a firm commitment to reliability, we have a grid that is now more capable of handling climate-change driven extreme heat events, which are becoming increasingly frequent,” said CPUC President Alice Reynolds.

California’s transformation proves that a clean energy future is compatible with reliability. In 2024, for the first time ever, California achieved 100 percent clean energy in the California ISO service area every three out of five days as the California ISO system reached 100 percent clean electricity for a period of the day on 219 different days. Solar energy output hit a peak of 19,600 MW, and battery discharges topped 8,000 MW in October 2024. Despite periods of extreme heat last year, the state did not issue a single Flex Alert in 2024, demonstrating the effectiveness of recent investment and coordination.

While California is well-positioned for summer 2025, officials caution that prolonged, Westwide heat events combined with sudden disruptions - such as wildfires impacting transmission lines - could still create tight grid conditions. As the fast-moving January wildfires in Los Angeles have shown, the growing volatility and sudden severity of climate-driven extremes continue to challenge expectations and highlight how quickly events can escalate.

“California’s grid is better prepared for extreme heat, but when multiple climate-driven events happen at once, the system could be pushed to its limits,” said California ISO Chief Operating Officer and Senior Vice President Mark Rothleder. “That’s why we remain vigilant and continue refining our emergency response playbook in light of new information and changing conditions.”

A combination of such events unfolded in 2022 when wildfires threatened key transmission infrastructure during a prolonged and widespread heatwave. The situation peaked on Sept. 6 when demand in the California ISO system reached its highest mark ever at 52,061 MW as residents across the state attempted to stay cool while temperatures were 10 to 15 degrees higher than average. 

Officials also highlighted how consumer engagement is a key factor in grid stability. Programs like Power Saver Rewards and public awareness of peak demand hours have helped reduce strain on the system, reducing the need for Flex Alerts in recent years.

“California’s success is a testament to smart policy, technological innovation, and the collective effort of agencies, utilities, businesses, and everyday Californians,” said Gunda. “But every summer brings unique challenges, and we must stay proactive.”

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About the California Energy Commission 
The California Energy Commission is leading the state to a 100 percent clean energy future for all. It has seven core responsibilities: developing renewable energy, transforming transportation, increasing energy efficiency, investing in energy innovation, advancing state energy policy, certifying power plants and preparing for energy emergencies.

About the California Public Utilities Commission
The CPUC regulates services and utilities, protects consumers, safeguards the environment, and assures Californians access to safe and reliable utility infrastructure and services. Visit cpuc.ca.gov for more information.

About the California Independent System Operator
The California Independent System Operator (ISO) is a nonprofit public benefit corporation focused on the continuous improvement and secure operation of a reliable grid for the benefit of consumers. It provides comprehensive grid planning, and ensures open, nondiscriminatory access to one of the world’s largest networks of high-voltage transmission power lines and operates a $9 billion competitive electricity market.

The ISO is at the forefront of integrating renewable power, storage systems and advanced technologies onto the grid to support state energy policies and decarbonization goals, while keeping reliability and cost effectiveness at the core of its operations and ensuring a sustainable and resilient energy future.