Can You Use Your Electric Car as a Battery For Your House?

✔ Electric vehicles could act as portable storage batteries in the near future

✔ The average EV battery has enough capacity to power a UK home for 4.8 days

✔ The UK government has committed just £14 million to developing the technology

If you’ve already paid the cost of installing an electric charger, you might be keen to learn whether you can also use your electric vehicle to power your home.

Electric vehicles are basically storage batteries on wheels, so it makes sense that you could use them this way.

We’ve investigated whether this is possible, looking at the current state of the technology, when it’ll be available, and whether an EV battery is actually big enough.

In the meantime, if you’d like to know what solar-plus-storage could cost you, fill in this short form and our expert installers will be in touch with quotes for you to compare.

What is a storage battery?

Storage batteries are large, rechargeable batteries you can use to keep electricity for later use.

They pair best with solar panels, as you can charge a battery during the day and use the stored electricity when the sun stops shining.

Some people use them to store electricity from the grid when prices are cheaper, but the typical cost of a storage battery — £4,500 — means this isn’t cost effective.

You’d be better off combining a storage battery with solar panels, though it’ll still take a long time to break even, because you’ll need to buy two batteries within the 25-year lifespan of a solar panel system.

Can you use an electric vehicle as a storage battery?

You can’t currently use your electric vehicle as a storage battery to power your home, but the technology is in development.

The process is called vehicle-to-grid (VTG) or vehicle-to-house (VTH) technology, and could soon see electric vehicles being used to power homes and businesses when they’re not being driven.

EVs will also be able to feed back into the grid when demand is high, which will be hugely beneficial as the UK transitions to more renewable energy sources.

Solar and wind power, which make up the bulk of green electricity generation, aren’t available 100% of the time, so a nationwide network of electric vehicle batteries will help to ease the burden.

The main hurdle is the fact you cannot retrofit existing electric vehicles with VTG technology. To make a vehicle capable of feeding back to the grid, its battery has to be specifically designed to do so.

Its charger also has to be created with this feature in mind, because it needs to be able to take the charge stored in the EV battery and direct it to your house or the grid.

Would more people adopt EVs if they could reliably power a home? Based on findings from our 2023 National Home Energy Survey, we’re not so sure — just 55% of Brits would want an electric vehicle even if it were free.

When will ‘vehicle-to-house’ charging technology be available?

The short answer is no-one knows yet, because manufacturers need to start building VTG and VTH-capable EVs en masse.

There are only a handful of proof-of-concept vehicles right now, as well as limited VTG EV charging stations being rolled out in trial locations across the UK.

There also needs to be a widespread adoption of the equipment that makes VTG and VTH possible. It’s not as easy as simply plugging your car into your house and having it function as a storage battery, unfortunately.

You need to have a bidirectional EV charger, which is one that’s capable of both charging your electric vehicle and using the charge in your EV’s battery to power your home.

What will be the benefits of ‘vehicle-to-house’ charging?

Being able to power your home with an electric vehicle has the potential to revolutionise the way the grid works.

Having potentially millions of electric vehicles acting as backup power sources during peak demand will massively reduce the strain on the grid.

This will be especially important as the UK moves away from fossil fuels and sustainable energy continues to make up a bigger portion of the grid’s electricity.

Having a robust energy storage network will help prevent the UK falling back on polluting power stations when the wind isn’t blowing, or the sun isn’t shining.

There’ll be significant financial benefits too, as households on time-of-use tariffs take advantage of cheaper electricity prices to charge their electric vehicle at night.

With VTH technology, you could run your home for days using your electric vehicle, at a lower cost than if you were just paying for on-demand electricity from the grid.

Will you need to install a new electric vehicle charger?

Yes, you will need a bidirectional EV charger, because ordinary EV chargers cannot power your home or feed electricity back to the grid.

Bidirectional chargers function more like inverters than standard EV chargers, meaning they can convert AC to DC while charging, and reverse this when discharging your EV’s battery.

Unfortunately you also need an electric vehicle capable of using a bidirectional charger, and right now there aren’t many available.

Ford’s electric F-150 Lightning pickup truck is one model capable of powering a home, but it requires specialist equipment and is only available in the US.

Other than an ongoing trial of 20 VTG-compatible cars from Nissan, there are currently no suitable vehicles for sale in the UK.

BMW, Peugeot, Volkswagen, and Fiat have all started working on models however, so it’s a safe bet that we’ll start seeing them in a few years’ time.

Is an electric car big enough to be a storage battery?

The batteries in some of the most popular electric vehicles on the market are more than large enough to fulfil a typical UK home’s electricity needs for days at a time.

Homes in the UK use an average of 2,900 kilowatt hours (kWh) of electricity per year, according to Ofgem, which is roughly 8 kWh per day.

A Tesla Model S has a usable battery capacity of around 95 kWh, so if it could be used to power your home, you could do so for 11 days.

Smaller, more affordable EVs like the Nissan Leaf also have large enough batteries to power a home for days. The Leaf’s usable capacity of 39 kWh will keep your home running for almost five days.

If all 1.8 million EVs on UK roads worked with VTG and VTH technology, and assuming an average battery capacity of 40 kWh, they could store a whopping 72 million kWh.

You could provide an entire year’s worth of electricity for roughly 24,800 UK homes, or meet the daily needs of 9 million households.

Summary

VTG and VTH technology isn’t quite there yet, but the potential it has to change the way the UK powers homes and businesses is immense.

Unfortunately, the UK government seems reluctant to invest heavily, with just £14 million going towards its Vehicle-to-X innovation programme.

More funding is needed to decrease the cost of VTG chargers, and to encourage people to adopt the technology when it becomes more widely available.

If you’d like to know what solar-plus-storage could cost you, fill in our simple form and we’ll put you in touch with our trusted installers. Just enter a few details and they’ll get back to you with bespoke quotes for you to compare.