Tesla Powerwalls supply most of record 745 MW California grid dispatch

California home batteries just set a new record, and Tesla Powerwalls did most of the work. On October 6, more than 85,000 Powerwall owners sent over 600 MW to the grid as part of a combined 745 MW dispatch announced by Sunrun, the largest seller of Powerwalls in the country. That's 28% higher than the record set less than a month earlier. The batteries responded to a heat wave, discharging during evening peak hours at the request of the California Energy Commission and utilities, under state programs called Demand Side Grid Support and the Emergency Load Reduction Program. These programs pay homeowners for sending power back to the grid when prices spike, which is why this kind of event keeps growing.

If you already have a Powerwall or similar home battery in California and have it enrolled in one of these grid programs, this is the kind of event that can put money in your pocket. Sunrun's CEO noted that participating customers get compensated for helping grid reliability. Pairing a battery with solar panels is generally what makes these programs worthwhile, since it gives you power to send back during peak hours.

Looking ahead, Sunrun says a separate project funded by Google and run with PG&E plans to enroll nearly 21,000 devices in the San Jose area, with dispatches expected to start this month. It's an early piece of a larger plan announced in June to build a much bigger virtual power plant to help power data centers, though that part of the deal is still non-binding.