The story. Arevon has broken ground on a 250-megawatt battery in Daly City that will store enough electricity to power 321,000 homes for four hours during peak demand. The $600 million Cormorant project, set to come online in 2027, won't produce a single watt — instead it will shift clean energy from when it's abundant to when it's needed most.

The bigger picture. California's grid shows why that matters. Natural gas still generates 49% of the state's electricity, while utility-scale solar provides just 10% (EIA, 2025). Solar floods the grid at midday when demand is moderate, then drops off in late afternoon precisely as air conditioners ramp up — the state recorded 625 cooling degree days in 2023 (NOAA), a measure of how much warm-weather cooling buildings need, which translates directly into evening electricity spikes. Without storage, grid operators fire up gas plants to cover that gap. A 1,000-megawatt-hour battery like Cormorant can absorb midday solar surplus and discharge it during those peak evening hours, directly displacing gas generation. The project was expanded from its original 188 MW design, suggesting demand for grid balancing is growing faster than developers anticipated. Arevon already operates 3.7 GW across California with another 550 MW under construction.

The tension. Four hours of discharge is enough to cover an evening peak, but not an overnight calm. California needs many more projects at this scale to meaningfully cut into that 49% gas share — and each one requires years of permitting, construction, and grid integration before it displaces a single gas plant.