Arizona is having a grid battery growth spurt. Will that last?

Arizona has become one of the busiest states in the country for building grid-scale batteries, the large installations utilities use to store solar power for use after the sun goes down. So far this year it has added more battery capacity than any state except Texas, following a similar showing last year. Recent additions include three big projects, each able to store enough power to run for four hours at 250 megawatts, plus several smaller ones. Arizona also ranked near the top for new solar construction.

This buildout stems from contracts utilities like Arizona Public Service signed several years ago, back when the state's main power companies were under pressure to move away from gas plants and had pledged long-term climate goals, and when federal tax credits made solar and storage attractive investments. Batteries make sense in a sunny state like Arizona because they let utilities save cheap daytime solar power for use later, instead of building more gas plants for evening demand.

That said, the political mood in Arizona has shifted. The state's utility regulators recently dropped a renewable-energy target, APS walked back its own climate pledge, and state lawmakers have pushed bills that would favor gas and other "baseload" power over wind and solar. APS is also now planning around longer-duration, more expensive batteries rather than the four-hour type common today. Construction should stay strong through 2026 and into 2027, but industry watchers say Arizona's run at the top of the battery-building charts may not last much longer. For homeowners, this doesn't directly affect individual upgrades or rebates, but it does signal how much cheaper solar power might be available on the grid in the years ahead.