But utilities will likely play the biggest role in ushering in a new era of electricity grids, says Max Baumhefner, a senior attorney at the Natural Resources Defense Council. One easy way they can encourage EV drivers help the grid is by offering “time-of-use” rates, which make it cheaper for owners to charge at times when the grid is less taxed—for example, when most folks are asleep at night. After watching 10 years of success with these rates programs, Baumhefner has concluded that “if we give people a little nudge, they will respond.” This sort of strategy can actually keep costs down for all grid users by helping utilities use the infrastructure they already paid for more efficiently, and avoid making upgrades.

The trick will be standardization, says Katie Sloan, vice president of customer programs and services at the utility Southern California Edison. As more people start sending battery power back to the grid, it would help if the various EVs and charging systems were technologically integrated. “It’s really analogous to what we saw in the solar industry,” says Sloan. “That was the first time we were moving from one-way power flow into homes really having bidirectional power flow.” Similarly, automakers, charging companies, and utilities need to work together to make use of EV batteries sitting in garages.

So how would this work for a customer? A utility might ask EV owners to make their batteries available during extreme heat events, for example. “The customer who’s participating knows when their vehicle might be called to provide power,” says Samantha Houston, a senior vehicles analyst for the clean transportation program at the Union of Concerned Scientists. “Giving the customer a heads-up that it might happen, even if it’s just a day ahead, that can be super helpful.”

This could happen through email or an app, or even a notification that appears on the dashboard of the vehicle itself. The customer should be able to opt out of a given event if need be, like if they’re expecting to need a full charge on their EV in order to leave town. (Tesla has a similar opt-in program for their Powerwall home batteries, which dispatch power to the grid during peak demand.)

This month, during a record heat wave, California officials credited residents’ response to a daily text alert warning them to stop unnecessary energy usage—for example, unplugging their EVs—with avoiding rolling blackouts. But those EVs could also be used to power their owners’ homes, decreasing the overall demand on the grid. “We feel like EVs can provide the notion of helping make power outages invisible for customers,” says Aaron August, VP of business development and customer engagement at Pacific Gas and Electric, one of California’s major utilities. That is, if the power goes out, your home should be able to switch to battery power without you even noticing. “These are mobile power plants. And with the right configuration, you can weather an outage for hours at a time.”