Kevala Finds 17.5 GW of Substation Headroom in California, Equal to 32% of the 2032 Peak Forecast
- Analysis Energy Storage Solar + Storage Integration
Marin Holt
- 0
- 8 minutes read
- Local load servable at summer peak: 17.5 GW
- Share of CEC mid-case 2032 peak forecast: 32%
- Southern California Edison: 9,188 MW (37% of its forecast peak)
- Pacific Gas and Electric: 6,560 MW (26%)
- San Diego Gas and Electric: 1,788 MW (39%)
- Dispatch window studied: 4 p.m. to 9 p.m., June through September
Kevala is a grid analytics firm. It says California distribution substations could host front-of-meter solar and storage serving about 17.5 GW of local load at summer peak. The Coalition for Community Solar Access commissioned the study and released it in August 2026. The three investor-owned utilities carry the whole figure. Southern California Edison could meet 9,188 MW of non-coincident summer peak load. Pacific Gas and Electric could meet 6,560 MW of non-coincident summer peak load, and San Diego Gas and Electric 1,788 MW. Kevala measured a window of 4 p.m. to 9 p.m., June through September, and set one hard constraint. Nothing is allowed to export from the distribution substation back onto the higher-voltage system. Against the California Energy Commission mid-case 2032 forecast, the total equals 32% of expected peak demand. The utility shares differ. SCE reaches 37% of its forecast peak and SDG&E reaches 39%, while PG&E, the largest system of the three, reaches 26%.
How the Number Is Built
The study counts installations, not dispatch. Kevala reports that the three systems could support 3,112 separate 5 MW solar-and-storage installations. Those serve 15,560 MW of local load. Systems smaller than 5 MW could serve an additional 1,976 MW. Add those two figures and the result is the 17.5 GW headline.
Multiply 3,112 by 5 MW and the answer is 15,560 MW exactly. The load served equals the nameplate installed. That is the shape of a headroom count rather than a dispatch simulation. The unit of the answer is a block of equipment that fits under the no-export rule, not an hour of energy delivered. The per-utility counts land the same way, at 1,657 for SCE, 1,129 for PG&E and 326 for SDG&E, summing to 3,112.
The Gap
Kevala states the limit plainly. The work is an estimate of technical potential, not a development forecast, and it does not test constraints such as land availability. A substation with electrical headroom still sits in a service territory. Somebody has to find parcels, sign interconnection agreements and win local approval.
Three further constraints go unpriced. The study does not carry a cost per kilowatt, a queue timeline, or a storage duration. Serving load from 4 p.m. to 9 p.m. is a five-hour obligation. A four-hour battery does not cover it unless solar is still generating at the front of the window. Late September is when that assumption weakens.
Why It Matters
The no-export rule is the interesting part of the design. By forbidding backfeed to the transmission system, Kevala confines the whole 17.5 GW to the distribution side of the substation. That framing skips the two processes that gate utility-scale supply in California. Those are transmission upgrades and the interconnection queue above the substation.
The utility spread also says something the headline number hides. SDG&E, the smallest of the three systems, shows the highest proportional headroom at 39%. PG&E, the largest, shows the lowest at 26%. The 32% of expected peak demand is a statewide average, and a target set off it would ask more of PG&E than its own substations appear able to absorb.
PG&E did not dispute the direction. Spokesperson Paul Doherty said the findings match the utility’s own view that distributed resources will matter to the state energy mix. He pointed to its SAVE virtual power plant and to a new SHARE program funded by Google. Stephanie Doyle of the Solar Energy Industries Association called the analysis a road map. She said it points to relief for a strained transmission grid. Neither statement is a commitment to procure anything.
Critical Perspective
The 17.5 GW is a count of 5 MW blocks that clear a no-export rule, and 3,112 of those blocks are what produce the 15,560 MW before smaller systems are added. The Coalition for Community Solar Access commissioned the work, and its members are the developers who would build those blocks. Pacific Gas and Electric answered by pointing at its own SAVE virtual power plant and a new SHARE program funded by Google, which is a different product from a 5 MW front-of-meter system sitting on a substation feeder. What would a utility have to file, and by when, for any of the 9,188 MW that Kevala found under Southern California Edison to turn into a procurement order?
Sources
- Utility Dive: Front-of-meter solar, storage could serve 32% of California’s 2032 peak load, study
- Coalition for Community Solar Access: New Study Finds Opportunity for More Than 17.5 GW of Distributed Solar and Storage
- Kevala: News and Resources
