For as long as electric vehicles have been on America’s roads, some have dreamed of the day when they stop freeloading on the electric grid and start contributing to it.
Recent developments suggest the day is getting closer.
It may seem that America is beating a retreat from the EV, with the Trump administration killing the $7,500 tax credit and paring back government support to nothing. But automakers and power companies seem to think EVs are here to stay — and that at least some EV owners will use their big batteries to power homes and neighborhoods.
The newest development comes from Honda, which said in September that an EV coming next year, the Acura RSX, will be capable of bidirectional charging, meaning it can not just receive but also send electricity through its charging cable.
It joins other vehicles that can do the same, including Tesla’s Cybertruck, the Ford F-150 Lightning, the Nissan Leaf and a slate of EVs from General Motors. Meanwhile, bidirectional charging stations — crucial but expensive — are starting to enter commercial production.
“The communications from the automakers has sent a massive signal that this is imminent,” said Zach Woogen, the executive director of the Vehicle-Grid Integration Council, a trade group of automakers and companies at the boundary of cars and the grid.
However, the imminent arrival of bidirectional power has been heralded many times before.
The technology has been in “pilot purgatory” for years, with utilities excitedly announcing new projects to tie vehicles to the grid. At the end of those pilots, however, the power companies have seen few tangible benefits, and in the end little has changed.
“It’s been almost 14 years and is still in this pilot-project phase,” said Lance Noel, a vehicle-grid expert at the nonprofit Center for Sustainable Energy.
His personal start date was his work at the University of Delaware, which pioneered “vehicle-to-grid” technology back in the 1990s, well before Tesla brought EVs into the mainstream.
While it seems simple in concept, the task of exporting electricity from car to grid is extraordinarily hard. Moving upstream demands concerted effort from automakers, charging equipment makers, software companies, electric utilities, state regulators and lawmakers.
“We’re talking about some of the slowest-moving institutions,” Noel said.
Could EVs solve the power crunch?
A grid in crisis seems to be spurring more urgency.
Electricity demand is on an endless growth curve, as homes electrify and artificial intelligence requires vast new data centers. Electricity prices are going up. In places like California, where the most EV-to-grid action is, higher temperatures and more severe wildfires prompted by climate change are making it more costly to deliver electrons.
“The challenges that the grid faces are immense, urgent and fundamentally different from the challenges of the previous 10 to 20 years,” Woogen said.
The benefits of bidirectional charging could be substantial. Electric vehicles are giant roving batteries that on most days use only a fraction of their juice.
Utilities believe that by charging and discharging at strategic times, EVs could work alongside other electric devices like heat pumps and solar panels in ways that are now barely possible and help to make electricity cheaper and more reliable.
Still, lots of factors are poised to delay the future.
Automakers are in the business of making cars, not power plants. Utilities are in the habit of using stationary power sources, not ones that wander off to Walmart. And it’s unknown if car buyers will want to factor in their electricity bill when shopping for a car.
“It’s a hell of a lot of work to get all of these things on the table,” said Noel. “It’s not going anywhere all that fast.”
State of the art
A new partnership announced this month between Honda and Southern California Edison, one of the state’s largest utilities, offers a glimpse of how vehicle-to-grid could become real.
It applies to customers who own the Acura RSX. (Acura is a sub-brand of Honda.) Its bidirectional feature means they can use their plugged-in EV to power the house, or at least its most energy-hungry appliances, like the washer, dryer, pool pump or heat pump.
To understand why that’s groundbreaking, take a look at what’s currently possible with EVs.
Ford already touts its F-150 Lighting as a tool for keeping the power on during a blackout. So goes General Motors with its range of Chevrolet, GMC and Cadillac EVs. Their home-juicing ability is formidable: The F-150’s 98 kilowatt-hour battery could theoretically keep the average Southern California Edison home powered for almost six days.
But that solves only one problem: navigating a blackout. It only works when the house is disconnected from the electric grid. And it only helps that one house.
Other solutions are starting to appear that harness the electric vehicle to help the larger grid — again, with limitations.
Starting this summer, Southern California Edison customers got the option to join a program called Charge Smart. Subscribing EV drivers essentially hand their charging schedule over to the utility. The driver sets certain parameters — say, to have the battery 80 percent full by 7 a.m. — and SCE promises to meet that goal.
Since a car is often parked for many more hours than it actually needs to charge, Southern California Edison can be strategic about when to deliver the power. For example, if the car is plugged in at midday when the region’s solar power plants are providing abundant electricity, the car could receive its charge then. Alternately, if a driver arrives home in the evening, when the overall grid is taxed by so many users, the charging session wouldn’t start right away. It would wait until the dead of night, when electricity is cheaper.
But this solution, cutting-edge as it is, isn’t bidirectional. It only turns an EV’s charger on or off.
The house that runs on a car
The new Honda alliance essentially creates for the utility a new, third option.
Instead of just turning the EV’s energy use on or off, it makes it possible to do the same with the much bigger electricity consumer: the house. At certain times, the grid could turn the task of powering the dishwasher, induction stove, lighting and other energy users over to the car.
It is part of a coming feature the utility calls “demand flexibility,” said Chanel Parson, the director of clean energy and demand response at Edison.
The goal is to make Acura RSXs the first vehicles that could tailor energy usage of individual neighborhoods. Buildings are linked together on distribution circuits, some of which may get overloaded with EVs in high-adoption areas. Turning EVs into power providers could help Edison avoid making costly upgrades — an approach that other utilities are also pursuing.
However, it’s still early days.
“We would love to run, but we are crawling first,” she said. “We want to master crawling quickly so we can get up and walk quickly,” and then perhaps run with an offering that could scale up.
None of this yet approaches what could be the final step: electric vehicles sending their power directly to the grid, like a miniature, local version of a wind farm or natural gas plant.
That is the possibility that most excites vehicle-to-grid experts. Americans drive their cars on average only an hour a day, leaving them idle 95 percent of the time, according to the U.S. Department of Energy.
Such a prodigiously large battery, used on most days so little, means that EVs could be knit together into “virtual power plants” that could one day provide substantial amounts of power.
The pilot projects that make the strongest use case for vehicle-to-grid, in fact, are the largest vehicles that linger the longest: school buses.
Electric school buses are “the low-hanging fruit” of vehicle-to-grid because so many of them spend the midday, and often the entire summer, parked in one spot, said Sam Houston, manager of the clean transportation program at the nonprofit Union of Concerned Scientists.
When it comes to light-duty cars, Honda and other automakers are looking to these horizons as they plan bidirectional technology for their vehicles.
“We envision our cars becoming a key part of people’s energy ecosystem,” said Chris Martin, a Honda spokesperson. “It’s going to be a little revolutionary, I think, in terms of how people think about their vehicles.”
Utilities, automakers and their silos
The limitations of the Honda-Southern California Edison partnership reveal how far bidirectional charging still has to go.
Its scope is narrow. It pairs one vehicle model from a single automaker with a single utility. The idea is so new that Parson of Edison shied from calling the Honda partnership a “project” or a “pilot.”
The same kinds of strictures occur elsewhere. In Northern California, Pacific Gas and Electric is starting to use EVs to power houses, but only with a handful of General Motors and Ford EVs. In Maryland, Baltimore Gas & Electric did a proof-of-concept project this summer with electric Ford F-150s — just three of them.
Utilities, by nature slow-moving and cautious, are especially careful when using a new power source that is always on the move.
“Each utility wants to get that hands-on experience for themselves before they scale,” said Houston.
However, there’s a sign that automaker silos are starting to bridge.
Last year, carmakers formed a joint venture called ChargeScape that now counts Ford, BMW, Honda and Nissan as members. It is a software company that aims to create a common platform for vehicle-to-grid.
“Automakers are looking for new revenue streams,” said Joseph Vellone, ChargeScape’s CEO, in an interview.
The challenge, he added, is that “bidirectional is a little tricky to get right from the hardware perspective.”
The legal hurdle
Another part of the bidirectional charging story occurs far beyond the experience of the driver: Lawmakers and regulators need to get on board before anything can happen.
Only a few states, including California, New York, Massachusetts, Maryland and Colorado, have created the legal and regulatory framework that allows utilities to participate in vehicle-to-grid programs.
California, long the leader in EVs, is the most advanced.
It has multiple programs that allow utilities to pay consumers, for example, to curtail their EV charging during grid emergencies, such as exceptionally hot days during the summer when everyone’s air conditioners are running.
And California enacted a law last year that empowers the California Energy Commission to require that electric vehicles have bidirectional capability. (So far, it hasn’t.)
And finally, the driver must be on board. It is unclear how many EV owners will want to electrically link their EV to their homes and their neighbors, even if the utility throws them some cash.
Experts say that bidirectional charging doesn’t need to involve every driver to have a lot of value.
“It may never be the case that hundreds of thousands of EV drivers are subscribing to an EV charging program,” said Vellone of ChargeScape. “But there will be a substantial subset of customers for whom the math works.”
