The grid is struggling, and the rise of EVs will only add extra pressure. Thanks to these vehicles’ potential as energy storage plants, however, they could be part of the solution
We’ve all heard it. That phrase trotted out with deadening familiarity by green sceptics: “Solar and wind are all very well, but what happens when the breeze doesn’t blow and the sun doesn’t shine? Have you thought of that, eh?”
For anyone who believes in the renewable energy revolution, it’s a frustrating comment, but it contains more than a grain of truth. Because, while increasingly cheap and efficient, wind and solar are undeniably intermittent. They don’t provide so-called ‘baseload’ electricity – always on, 24/7 – in the same way that conventional power plants can.
That’s a problem, as electricity is notoriously hard to store: ideally, you balance supply and demand. Hence the appeal of ‘baseload’ gas, coal or nuclear plants, which can be brought into play to match demand. Hence, also, the need to pay wind generators to turn off their turbines when excess supply is being produced: around £180,000 spent per hour in the UK alone. Large battery banks are coming onstream, but they’re expensive and have limited capacity.
Across Europe, sales of electric vehicles are up 34% in the 12 months to January 2025
As renewables’ share of electricity generation soars – wind and solar together account for 28% of European production – so does the challenge of balancing that intermittency with the demands of the grid.
All this, too, at a time when there’s growing pressure to decarbonise power supplies in order to hit climate targets. For Europe in particular, that means shifting away from using gas or oil to heat our buildings, and petrol or diesel to drive our cars. Instead, we need to electrify our transport and heating, which will massively increase electricity consumption. Some estimates predict that the share of energy produced by electricity could double or more by 2050. And climate targets necessitate that all this electricity be produced in as green a way as possible. That includes hydro and (some would say) nuclear, but crucially, more wind and solar.
Electric vehicles are a key driver of that demand surge. Despite talk of a backlash against them, sales continue to grow. Across Europe, EV sales are up 34% in the 12 months to January 2025, even as the overall car market shrinks. In the UK, more than a quarter of cars sold are now electric, and surveys show that more than half of British drivers say their next car will be an EV.
That at least sounds like wonderful news for the climate: here we are, well on our way to decarbonising motor transport. Except for the inconvenient fact that all those EVs need charging, putting more demand on a stressed-out grid. One of the most popular times for charging is early evening, which happens to coincide with peak demand for electricity across the board.
Put like that, the rapid growth of EVs suddenly looks less like a feature of a greener power system, and more like a bug. This could put electric cars on a collision course with climate aspirations – except for one much more convenient fact: electricity that goes into an EV battery can be exported out of it again.
A rapidly growing fleet of EVs could provide ‘vehicle-to-grid’ potential on a scale that was unimaginable a few years back
EVs have surprisingly chunky batteries, explains Dr Femke Nijsse, senior lecturer in innovation, energy and climate at the Global Systems Institute at the University of Exeter. “A typical EV battery could power your house for three days”, she says, adding that their capacity is up to 20 times that of typical home battery systems, such as the Tesla Powerwall.
This helps turn a problem – more demand on the grid from EVs – into a solution: a rapidly growing fleet of distributed energy storage plants, providing ‘vehicle-to-grid’ (V2G) potential on a scale that was unimaginable a few years back.
A 2023 study published in Nature Communications suggested that short-term grid storage needs across much of the world could be met in full by EV batteries, both in cars, and at ‘end-of-life’ stage, when they can still function as mini storage plants. Startup Voltfang, for instance, has been pioneering this approach for several years.
A typical EV battery could power your house for three days, according to Dr Femke Nijsse, senior lecturer in innovation, energy and climate at the Global Systems Institute at the University of Exeter
Sounds too good to be true? Well, there are some significant hurdles to overcome, says Nijsse. Two are technical, one is economic. First, the battery has to be capable of ‘bi-directional’ charging: able to both take on electricity and export it. Second, the local electricity system needs to have a complementary ability to send power to and fro, in just the right amounts and at the right times to balance the grid.
Third, a market mechanism needs to be present to make it worthwhile for both EV owners and grid operators.
Fortunately, progress is under way in all three areas. The technical side is – relatively speaking – the easy bit, explains Alex Schoch, head of flexibility at UK-based Octopus Energy. The rise of rooftop solar means that the provision for households to export to the grid is already widely in place, both in Britain and Europe.
Every major brand of car manufacturer now has vehicle-to-grid firmly in their sights
As to the tech needed for the cars themselves: “If you’d asked me that two years ago, I’d have said it was still [a challenge]. But now, across Renault, Ford, Kia, Hyundai, BMW, VW … every major brand of car manufacturer, whether EV only or a legacy automaker, now has vehicle-to-grid firmly in their sights.”
There is one remaining “technical wrinkle”, in that only about half the cars so equipped are able to convert the electricity they produce from DC to AC – the sort used in households. Without it, Schoch explains, a conversion kit has to be installed separately in the home itself. A typical example is the Quasar 2, a wall-mounted box about the size of a large atlas, which both stores the electricity and converts it from DC to AC. It costs around £5,000.
“It’s a VHS v Betamax debate”, says Schoch, suggesting that onboard conversion will likely emerge the winner, as it keeps things simple for the householder.
Vehicle-to-grid could both help to balance the grid and save EV owners money
As to the grid’s ability to absorb this additional power, the advantages of having a massively increased amount of energy storage on hand is rapidly driving the innovation needed. A trial conducted by the UK’s National Grid in partnership with Octopus proved that V2G could both help to balance the grid and save EV owners money, thanks to a discount on their charging fees. It found that if all 10m EVs anticipated to be in service by 2030 were involved in grid balancing, it would save around £100m per year in overall system costs, some of which could be used to reward participating EV owners.
Sophisticated software can now manage the flow of power in and out of the batteries, to match overall supply and demand, says Schoch. Octopus uses the Kraken system, which means: “You put in our app what time you want the car to be ready by. And then, in the background, Kraken creates an optimised charging schedule within those parameters that helps balance the grid, to make it as green as possible, without paying to turn off wind turbines.”
Octopus is now launching a ‘power pack’ tariff which, the company claims, could save a typical EV driver around £880 per year. The absolute key, Schoch says, is that the driver knows they needn’t worry that their car won’t have enough power to go wherever they want, at short notice. “That’s non-negotiable”, he promises.
Is V2G technology the key to a harmonious relationship between EVs and renewable energy?
As to the overall impact of V2G on the energy landscape, it could be a fourfold win, according to a new study from professional services firm EY. V2G can slash the total cost of ownership for EV owners, provide grid balancing solutions, reduce energy system costs and help accelerate renewable energy adoption.
Together these could amount to a positive tipping point, one that tips the balance in favour of both electric mobility and renewable energy.
The more this new landscape takes shape, the more striking the benefits will be, concludes Nijsse. As the grid works more effectively, it can make more use of renewables, she says, “so electricity becomes cheaper, then EVs become more attractive, so then more are deployed, and thanks to ‘learning by doing’ and economies of scale, the price then goes down. It’s a virtuous spiral, and it’s just beginning.”
Illustrations: Ibrahim Rayintakath
Three ways to shift the V2G revolution into high gear
1. Strike while the iron’s hot
If you’re in the market for a new car, now could be the time to go electric.
2. Do your research
Go with a model that includes battery and charging technology that supports V2G.
3. Connect the dots
Ask your electricity supplier whether they offer, or plan to offer, a tariff that supports V2G. Consider switching if they do not.
This article is part of Positive Tipping Points, a series about people who are discovering ways to trigger significant and cascading positive changes within the climate crisis. Produced by Positive News in partnership with Imagine5
