Your EV Could Soon Charge Your House, Tools – and Even the Grid

EV adoption might be slow, but EV technology is growing rapidly.

Electric vehicles accounted for only 9% of light duty vehicle sales in the third quarter of 2024. While that figure is growing quickly -- with the National Renewable Energy Laboratory estimating 30 to 42 million EVs in the US by 2030 -- what's new with EVs goes beyond saving money on gas or helping to reduce carbon emissions.

The new frontier for EVs is called bidirectional charging, where your car's big battery could provide backup power to your home during a power outage. Companies like Ford, GM, Volvo and Tesla have all adopted bidirectional charging on some models in their lineups, and many more manufacturers intend to have it available on all their models by 2025 and 2026. 

With the increasing adoption of bidirectional charging technology by EV manufacturers, bidirectional charging could replace home battery backup options like the Tesla Powerwall. Solar batteries provide backup power whenever you need it, but they cost thousands of dollars to install and you only use them for one thing. Bidirectional charging offers EV owners two-for-one solutions, giving them mobility and putting their EVs to work while sitting in the garage. 

"Bidirectional charging will become more widespread, and 2025 marks an inflection point for bidirectional technology," said Thomas Martin, director of sales engineering at Swtch, a company that offers EV chargers for multitenant buildings. 

CNET spoke with experts from automakers and researchers who study the technology to figure out what lies next for the connection between your home and your car. Will bidirectional charging really be able to replace standalone home backup batteries? And what stands in the way of this technology going from fairly niche, even among EVs, to mainstream?

Here's what the future of bidirectional charging looks like in 2025. 

The 2024 Chevrolet Silverado EV RST can power a home for weeks with its V2H system.

GM

What does bidirectional charging look like in 2025? 

With major automakers bringing bidirectional charging to their EV lineups, we expect to see significant adoption starting in 2025, with companies moving to not just support vehicle charging for the home, aka "V2H," but vehicle charging for everything -- "V2X." 

"With companies like GM committing to rolling out V2X tech in all their vehicles by 2026, the number of vehicles that can participate in V2X will grow very quickly," said Martin. "This will help us reach a critical volume where the technology will fuel market participation." 

However, it's not just customer adoption and technical capability at play here. The two big trends we're likely to see in the coming year involve commercial fleets and home energy management. 

V2G is going to become a much bigger deal for fleet owners 

The future of bidirectional charging is going to look different for fleet owners compared with regular consumers. Take the example of a UPS warehouse that uses a bidirectional charging system for its trucks in a vehicle-to-grid, or "V2G," setup. According to Omer Onar, research and development staff at Oak Ridge National Laboratory, the system used by UPS allows you to charge wirelessly while providing power back to the grid. 

This microgrid setup can technically work for anyone with a large fleet, including school buses, churches, car rentals, trucking companies, public transit and more. These larger fleets operate on a controlled and predictable schedule, which is valuable for V2G programs. 

UPS already has a few electric delivery trucks, like this one in London.

UPS

A power management system is necessary 

Alexander Petrofski, head of Volvo Cars Energy Solutions, envisions that customers will need an energy arbitrage system for their EV, with an algorithm that optimizes the charging and discharging of their car in relation to the consumption of their house as well as electricity prices. 

To efficiently and effectively use bidirectional charging, customers will need a system that automatically charges vehicles when costs are low and sells the power back to the grid when costs are high. This arbitrage feature already exists in home batteries like the SolarEdge Home Battery and Tesla Powerwall 3, but car manufacturers are also getting into the game. 

Ford has partnered with Sunrun and BGE in a pilot program to demonstrate the capabilities of the F-150 Lightning and how it can power the home and feed energy back to the grid. GM has also launched the GM Energy PowerBank, a stationary storage system that lets EV owners store power and transfer energy to the grid. It comes with a full home energy management system that can power a home during an outage and offset higher electricity rates during peak demand. 

GM

Virtual power plants also require a few more pieces to fit together. You need a vehicle and a home inverter that's connected to a virtual power plant program and that system needs to be maintained by the VPPs and utilities, which isn't as straightforward as it sounds. 

On top of that, every home charger needs to be set up and connected to the internet to participate so the VPP can make an educated guess about how many vehicles with sufficient charge are plugged in at a given moment. For instance, the program can't pull energy out of cars that are in a 5-10% state of charge; those vehicles need to charge up first so the owners still have use of them. 

According to Martin, VPP and grid services are only likely to see greater success when there's more volume in the market. When more people install the system and the number of connected vehicles increases, achieving predictability becomes easier. 

Can bidirectional charging replace your home battery? 

"I never had a home battery," said Ryan O'Gorman, energy services and V2G business lead at Ford. "I've just had the F150 [Lightning]. We had a very severe storm here in Michigan over the summer that came through my area and wiped out trees and power lines. [My area] was out of power for three days -- but I wasn't. I ran off my truck the whole time and when the power came back, I had close to 100 miles left." 

The average EV owner isn't likely to notice the drain from using their vehicle as a battery backup. "The nice part of a vehicle is when it's plugged in, taking that 15-30 miles from the vehicle is almost not observed by the consumer," said O'Gorman, "and you can charge it back with less than an hour, depending on the vehicle." 

However, not all the experts we spoke with agreed that bidirectional charging will wholly replace home batteries. "If you live somewhere remote and need something better suited to longer-term energy backup, it's probably more economical to get a home battery system," said Martin. "That will probably store more energy and not cause problems if you still need to get around during a days-long power outage."

"We don't really see an either-or," said Ben Clarin, senior project manager at the Electric Power Research Institute, a research organization that provides independent and objective industry expertise. "Both of them can provide the capabilities of supporting people through power outages." Clarin believes there's room for bidirectional charging to coexist with home battery systems and it's unlikely to see systems like the Tesla Powerwall wholly replaced by bidirectional charging. 

Clarin said bidirectional charging can work in residential use cases where a home battery isn't practical, such as in a multifamily building where tenants can't have their own battery backup due to space and expense. 

Ford's F-150 Lightning Pro, the least expensive electric pickup, targets commercial applications rather than private owners.

Antuan Goodwin/CNET

The current state of bidirectional charging

As the name suggests, bidirectional charging is a process that lets your vehicle convert its stored direct current energy into alternating current electricity, feeding power back into your home or the grid. This flips the script from the traditional, one-way charging process for EVs, which typically takes AC power from a wall socket to an EV charger and car battery that converts it into DC energy. 

The technical implementation is fairly straightforward, but the real potential in bidirectional charging lies in all the different possible use cases. For instance, one implementation is V2H charging, where your vehicle can serve as a backup generator during a power outage. 

"I think there are two basic use cases," said Aseem Kapur, chief revenue officer at GM Energy, a division of GM that provides solutions for energy storage, EV charging and more. "One is a pure resiliency application where you use your vehicle and borrow [power] for your home in the event of outages. That makes for a very valuable application in a scenario where you can now use your vehicle as a dual asset right beyond mobility. [It can] serve as an energy asset, combining it with stationary storage." 

The Nissan Leaf was a pioneer in bidirectional charging functionality. 

Nissan

When fully charged, the average EV holds 60 kilowatt-hours of electricity, which can power a home for about two days, but depending on usage, it can often last even longer, which makes it quite practical to use your EV as a home power backup. 

"If I look at your standard, off-the-shelf stationary storage [it has] somewhere between 7 and 13 kilowatt-hours of power," O'Gorman said. "That's fantastic, but that's really [only] somewhere between 15 and 30 miles on the vehicle -- these vehicles can get 300 miles." Essentially, that means the average person using their EV as an emergency power option is unlikely to really notice any significant drain on their vehicle's mileage, making it practical to use as a power backup during emergencies. 

There are also options like vehicle to load, or "V2L," which allows you to use an adapter to let your vehicle power things like camping equipment, power tools, home appliances and other devices. "For basic vehicle-to-load, there's basically no barrier to entry," Martin said. "If your vehicle has an outlet for you to plug an extension cord into, you're all set to plug your devices in."

That makes V2L the first bidirectional charging use case the average customer is likely to experience. There's also vehicle to vehicle, or "V2V," which can provide power to an EV that's run out, similar to how you can use your car battery to jumpstart another vehicle, though a more apt analogy might be siphoning gas from your tank to put it into another vehicle. 

Challenges of widespread bidirectional charging adoption 

The switch to bidirectional charging is not as simple as a software update or a new piece of equipment. It's going to require manufacturers and consumers dealing with a host of hurdles.

Vehicle capability and charger capability 

"[T]he biggest barrier to bidirectional charging and other vehicle-to-everything technologies and applications is vehicle capability," Swtch's Martin said. "While there are chargers in the field that support V2X, the limited number of compatible vehicles makes the charger tech a bit less impactful today." 

However, that's set to change in the coming years. Just at GM, Kapur listed the new Chevrolet EVs that launched, including the Equinox, Blazer and Silverado, plus the Cadillac Lyriq and GMC Sierra. All of these vehicles are bidirectionally enabled and work with GM's vehicle home system. 

The 2023 Ford F150 Lightning comes with a free bidirectional charger when you get the extended-range battery option.

Marc Ganley/CNET

The most prominent current example is the Ford F150 Lighting with its Ford Connected Charge Station Pro, a $1,310 bidirectional charger that comes free with some models of the electric truck.

We expect other car manufacturers to follow suit and enable their vehicles to use bidirectional charging. Volvo has confirmed that the Volvo EX90 will be capable of bidirectional charging and is working on an AC bidirectional charger in Europe. The Swedish automaker also has a partnership with dcbel, a home energy company, to bring a bidirectional DC home energy station to the US market.

Cost of installation and upgrade

Bidirectional charging is more expensive than basic EV charging. "If you want to do more, like connect your car to your home as a battery backup or connect to the grid for V2G programs, the main obstacle is expense," said Martin. "You need to purchase both a compatible charger and disconnect switch, and that's going to cost thousands of dollars -- and you'll need to find space for it."

The space and cost may make bidirectional charging in a multifamily building prohibitive, but even single family homeowners may find unexpected costs. Some homes have older wiring and older electric panels that don't support 200-amp electrical service. In order to take full advantage of bidirectional charging, some homeowners may require a panel upgrade to get to the charge level they want, which can be another expense. 

O'Gorman points out that certain bidirectional chargers, however, like Ford's Charge Station Pro, can downrate their charging to whatever the installation load supports, so in that regard, it's not strictly necessary to upgrade your panel as long as you can live with not getting the full 19kWh of charging the charger is capable of. 

Regulatory environment 

A significant component of bidirectional charging depends on the regulatory environment. The process of buying and selling electricity back to the grid is usually left up to individual states and utility companies. Some states might have net metering, allowing you to be compensated for excess energy produced by your solar panels. 

"[I]t's typically referred to as an interconnection agreement in the industry," said Andrew Meitz, chief engineer for electric vehicle charging and grid integration at the National Renewable Energy Laboratory. "Any device that you add to your house that's able to export power back to the grid needs to be listed, and then it needs to be declared to the utility that you have a generating device." 

Energy arbitrage and capacity arbitrage -- that is, the payment you get for energy stored and returned to the grid by your home battery or EV -- can also vary significantly between states. Internationally, the European Union has called for changed legislation because of grid fees and taxes on buying and selling electricity that make it difficult for private customers to get involved. 

Your home battery's power output determines the number of loads you'll be able to backup.

Petmal/Getty Images

These are challenges that are very similar to those that exist for virtual power plants. "The regulatory landscape for virtual power plants across the United States is organized across not just all 50 states, but even individual utility territories within each state," said Mark Dyson, RMI's managing director of electricity, "and that's one of the main challenges that we see is facing or impeding growth of the market overall."

The key problem is that customers need a reason to want to put energy back into the grid, Dyson said. "Those benefits are unavailable or unattractive unless utilities and regulators make them available to customers through rate design, through incentive programs, through changes in the way the utilities plan and operate their grids, to really take advantage of this resource at the utility scale." 

Does bidirectional charging impact car battery life and wear? 

The average EV user likely won't have to worry too much about wear and tear on the car battery from bidirectional charging. 

"Our data shows that this should not be an issue for the regular consumer," said Petrofski. "As long as bidirectional charging is carried out in a dimensioned and limited way, it will not have a significant impact on battery life." According to Petrofski, Volvo will limit the bidirectional functionality for customers using too much of their vehicle's battery. This is based on customer-specific conditions, driving and charging behavior. 

"The thing that degrades batteries fastest is stressing the battery outside of ideal conditions," said Martin. "If you often charge quickly to a high state of charge and do so in really hot or cold weather, that's the likeliest thing to start producing noticeable degradation." 

Smith Collection/Gado/Getty Images

With that said, on a technical level, the EV shouldn't suffer from problems if you use it as a home battery backup, according to Martin. "Today's EV battery chemistry is more than capable of handling the additional demands of sending power back to the grid or powering a home for a few days, even multiple times a year. Most vehicle owners should have no problems at all." 

The other good news is that every manufacturer we spoke with confirmed that bidirectional charging is a supported use of their EVs. It won't void or modify the warranty, which is a concern often raised by customers.