GM is working with PG&E to turn electric vehicles into a virtual power grid in California

General Motors and utility Pacific Gas and Electric are teaming up to determine how electric vehicles can be used to power people’s homes during a blackout — or even feed power back into the grid during times of peak demand. The pilot will take place in PG&E’s home state of California, where wildfires are putting strain on the state’s energy infrastructure.

GM is the latest automaker to team up with a utility around the idea of “vehicle-to-grid” technology. (PG&E has also partnered with BMW around a similar idea.) The idea is to use bi-directional charging equipment to push and pull energy from electric vehicles at any given time. In essence, it treats high-capacity batteries as not only tools to power EVs but backup storage cells for the electrical grid.

GM expects that it will have “1 million units of EV capacity” in North America by 2025, said Rick Spina, vice president of EV commercialization at the company. Unlike other automakers, GM has yet to release an EV with “vehicle-to-load” capabilities, but Spina said that it plans on correcting that via an over-the-air software update soon.

“We’re on the cusp of turning our EVs into a power source for our customers,” Spina said. “And these customers aren’t even aware of it.”

This summer, GM will test bi-directional charging technology at PG&E’s lab in Northern California, as well as the “software-defined communication protocols” that will enable power to flow from a charged EV into a person’s home automatically when the power fails. Later, GM and PG&E will identify a select group of customers in California to test these technologies in their own homes, with the goal of launching wider customer trials by the end of the year.

“Imagine a future in which there’s an EV in every garage that functions as a backup power source whenever it’s needed,” Spina said.

There’s still a lot to be determined, such as how GM will convert power from the EV battery from direct current to alternating current. Spina said the company has yet to determine whether that process will happen in the vehicle itself or through another piece of equipment, like a wall-mounted charger.

The potential, Spina said, is to transition away from dirty, gas-powered generators toward something cleaner and more useful. The average California home uses around 20 kilowatt-hours of power a day, while a Chevy Bolt has a battery with 60kWh capacity, Spina said. That translates into at least two or three days worth of electricity for a single home, he said.

Other possibilities include using a broad swath of EVs to “smooth” the grid during times of peak demand, like a summer heatwave. In those scenarios, Spina said he could envision some kind of payout of “customer benefit” to those EV owners who are using their vehicles to feed power back into the grid.

PG&E, which is based in San Francisco, serves a territory that’s a fertile testing ground for vehicle-to-grid technology. It’s already home to more than 320,000 electric vehicles. That’s roughly 20 percent of all electric cars in the US, according to the utility. By 2030, 5 million EVs are expected to be on the road in California. (Last year, California became the first state to ban the future sale of internal combustion engines.)

With enough EVs connected to the grid, they could become sizable “virtual power plants.” These are basically just networks of connected batteries that utilities might be able to call upon collectively when they need more juice. Interconnected residential solar power systems can also serve the same purpose. The hope is that by working together, all of those batteries can alleviate stress on the grid whenever there’s peak demand. Virtual power plants could also replace polluting, fossil-fueled “peaker plants” that utilities have historically relied on when they’re short on energy.