Sunrun, Tesla break residential VPP dispatch record in California
Home solar and storage firm Sunrun and EV giant Tesla have set an energy dispatch benchmark, with residential batteries around California creating the largest residential virtual power plant (VPP) dispatch event on record.
A total of more than 140,000 batteries dispatched more than 580 MW of peak power to the Golden State’s grid on Sept. 9, officials from the two companies say. That amount of electricity is enough to power all households throughout Sacramento County — all census-estimated 571,000-plus of them — during peak hours.
“Sunrun’s distributed home batteries are operating at a scale larger than many peaker power plants combined,” says Sunrun CEO Mary Powell. “Families depend on their Sunrun energy systems for outage protection and energy independence. This historic dispatch shows that the benefits of distributed energy go well beyond individual households as we help control the cost of electricity for all Californians and reduce the need for new costly poles and wires.”
The massive dispatch event was the west coast state’s answer to spiking energy prices during early September’s heat wave. High temperatures led to elevated demand for electricity, in turn creating an outsized increase in energy prices.
The companies say that the dispatch occurred for a three hour evening period at the request of the California Energy Commission and various utilities.
“Sunrun and Tesla coordinated (580 MW) of residential battery capacity during the event—combining (517 MW) from Tesla Powerwalls with (63 MW) from additional batteries,” Sunrun representatives say in a statement. “110,000 Powerwalls participated in the event; more than half of those (55%) are owned and operated by Sunrun. In addition, Sunrun dispatched more than 30,000 of its customers’ batteries from other manufacturers.”
Proof of concept
The massive dispatch event was a coordinated effort by Sunrun and Tesla, along with the California Energy Commission’s Demand Side Grid Support (DSGS) program and the California Public Utilities Commission’s Emergency Load Reduction Program (ELRP). The two entities called in their respective energy dispatches thanks to a combination of excessive heat and rising energy prices, which hit a dispatch tripwire after showing potential to cross $200 per MWh.
Despite the record-breaking performance from Sunrun and Tesla’s residential distributed power plant, the two companies say there is still room for more.
“Together, Sunrun and Tesla delivered more than (140 MW) of battery capacity to the grid,” Sunrun officials say. “Had the dispatch events from Sept. 9 and 10 occurred on the same night, Sunrun and Tesla would have had the ability to deliver over (720 MW) in a single dispatch.”
The dispatch event and its potential for even greater usage in an emergency is proof of concept for Sunrun, Tesla, and Renew Home’s wider mission. The companies’ combined initiative to unlock more than 16.8 GW of capacity from home batteries and other distributed energy resources was announced in June.
Research firm The Brattle Group finds that in total, these VPP programs from Sunrun and Tesla could provide up to $206 million in energy savings for California residents by 2028. These savings would benefit all grid-connected customers, and participants could further benefit from direct compensation for the power they give back to the grid.
