You can’t tell when you’re passing one on the highway, but an electric vehicle may well have a superpower. It charges by plugging into the electric grid, of course, but it might also be able to send energy back into it. For a growing number of EVs, this vehicle-to-grid technology, or V2G, creates a revenue stream for drivers, who utilities pay to tap into their batteries when demand on the grid spikes.
Utilities across the country are pursuing pilot projects for the tech, figuring out how to coordinate hundreds, thousands, and eventually millions of EVs. To that end, today a coalition of companies—Eversource, National Grid, EnergyHub, Sunrun, and the Mobility House—is launching an early test of the technology in Massachusetts so utility customers can give it a try. Lessons learned here and elsewhere could drive the technique into the mainstream, making the grid more reliable and electricity cheaper, even if you don’t own an EV. “It’s great to have Massachusetts stepping into the lead here and doing this because these learnings are what’s going to allow this technology to scale,” said Chip Silverman, director of grid services at Sunrun, a solar and battery company.
In the new system, participants hook into an existing program called ConnectedSolutions, which allows homes to run off their residential batteries, among other things. Then when there’s a “demand response” event, like during a heat wave, EV batteries can help the grid keep up. Participants are compensated for this, just like some homeowners who provide energy from their solar panels.
“It’s really kind of a small number of hours per year that you’re discharging the battery,” said Russell Vare, vice president of vehicle-grid integration at the Mobility House North America, a provider of charging infrastructure. “It’s not necessarily like a daily discharge. It’s just during those peak times the events are called.”
Utilities like V2G because they’re dealing with escalating, overlapping challenges. For one, the demand for electricity is growing as more power-hungry data centers come online and people switch from internal combustion cars to EVs and from gas furnaces to heat pumps. At the same time, utilities are trying to ditch gas and coal in favor of renewables like wind and solar. These clean technologies, though, are intermittent, in that the wind isn’t always blowing and the sun isn’t always shining. Utilities need ways to bank energy for later use, which is why they’re building storage facilities and even using the Earth itself as a giant battery.
Already, Americans are struggling with skyrocketing energy prices for a variety of reasons. Utility shareholders are reaping profits, for instance, and customers are footing the bill for improvements, like burying power lines so they don’t spark wildfires or come down in a storm. Building battery facilities and stringing transmission lines will add still more costs—the inevitable price to pay for a cleaner, more reliable grid.
Except some of that spending may indeed be avoidable: The promise of V2G is that it can make electricity cheaper. While participants need a bidirectional charger to send energy back to the grid, a utility doesn’t need to reinvent the system as a whole. EV batteries are an existing, widespread, and reliable source of backup energy to tap into in times of high demand, like during the summer when everyone is running their air conditioning. “It’s the cheapest cost of flexible energy storage that will be available for the grid,” Vare said.
The hotter the planet gets, the more enticing V2G looks for utilities. People need additional AC to stay healthy, but the appliances require lots of power to run. If that energy isn’t coming from renewables, it’s causing even more warming and increasing demand for AC, and on and on. In a V2G system, vehicles that follow predictable schedules, like school buses and municipal fleets, will be especially useful, in addition to their batteries being enormous stores of energy. Even a typical EV battery, though, has around six times the capacity as a backup unit mounted outside a house.
