Summer readiness activities are well underway
Although the calendar still says winter, this week’s weather forecast tells a different story. Summer doesn’t officially begin until June 21, but teams across the California Independent System Operator (ISO) are already deep into preparations for the summer season. That is the time when electricity demand typically peaks across many parts of the West, and grid conditions face their greatest potential stress.
The ISO’s meteorology team is currently forecasting a hot summer across much of the region. The heat is expected early in the season, followed by a brief mid-summer reprieve before temperatures warm up again in late summer and fall.
Parts of the West are already getting a taste of what may come with the unusual early mid-March heat wave. Despite record-breaking temperatures for this time of year, the grid is performing well under these conditions.
Meanwhile, members of our Resource Assessment and Planning team are working on the ISO’s 2026 Summer Loads and Resources Assessment. This annual analysis evaluates resource availability on the grid for the months ahead, including the latest projections for hydroelectric power based on seasonal precipitation. While the report will not be published until May 4, one takeaway is already clear: the grid is heading into the season with considerably more resources online than last year.
In 2025, the ISO added 7,253 megawatts (MW) of new capacity to the grid. Nearly 5,000 MW of those additional resources—4,789.33 MW to be exact—was battery energy storage systems. These mostly four-hour, lithium-ion batteries play a critical role in meeting summer demand on hot evenings when the load remains high and solar power is ramping off the system.
With last year’s additions, the ISO has integrated 33,839 MW of capacity since 2020, including 16,003 MW of batteries, providing grid operators with more tools as demand grows.
Grid resources also received a boost recently from the Diablo Canyon nuclear power plant returning to full availability after annual maintenance.
That good news, however, is just part of the story. No power grid is immune to challenges during emergencies such as extended periods of extreme regional heat or cold, and natural disasters like wildfires, and other emergencies. Addressing these risks depends on strong planning, communication, coordination, and energy conservation, efforts that have been continuously strengthened as grid complexity has increased.
“Our coordination and communication with other entities, as well as our joint training exercises, have definitely increased with the growing complexity of the grid,” said John Phipps, the ISO’s Executive Director, Grid Operations. “With the dramatic change we’ve seen in technology in recent years, we have stepped up all those activities that are so important for maintaining reliability.”
Here is a short list of some of the activities that are already underway for 2026 or that will be soon:
- Updating the ISO’s “Extreme Weather Event” playbook, which describes potential actions taken by the California ISO before and during an extreme weather event to maximize the likelihood of maintaining reliable operations.
- Coordinating with partners at the Governor’s Office, the California Energy Commission and the California Public Utilities Commission to align roles, responsibilities, and messaging during an extreme event.
- Conducting multiple internal and external emergency response exercises in April and May, including tabletop drills.
- The annual Summer Readiness Leadership Roundtable May 5 brings together utility executives and other senior officials to discuss reliability risks and look for opportunities for additional coordination in advance of summer.
- Hosting the annual RC West summer outlook meeting, with briefings from CalFire and the Western natural gas system operators.
- After the RC West meeting, we also host a summer readiness workshop for system operations managers from California utilities.
- Closely monitoring current and planned transmission system maintenance outages, with the system expected to be near full capacity by early June.
Earlier in March we completed our annual RC West restoration drills, working with about 180 operators around the West on simulated exercises to get their electrical systems up and running again if they have outages. These drills, required by the North American Electric Reliability Corporation, are designed to ensure that each balancing authority within RC West’s oversight understands, maintains and can deploy its plan to rebuild its system in the event of a system disruption.
As we head into summer, we are doing so with added resources and the benefit of proven planning, outreach, communication, and coordination to help manage potential challenges.
For anyone wanting more information about summer readiness activities and related matters, you can go to the following links:
