Vehicle-to-grid technology in a nutshell.
With the rise in popularity of electric vehicles (EVs) over the last decade, you might have heard of the concept of vehicle-to-grid, or V2G technology. But what exactly is vehicle-to-grid and how can it help both EV drivers and the UK’s electricity supply?
In simple terms, vehicle-to-grid is a way of using electric vehicle batteries to help balance the electricity grid. Without vehicle-to-grid technology, EVs just take electricity from the grid when they’re charged. But with this technology, EVs can discharge their batteries back into the grid when it needs it.
Harnessing EV batteries to support the grid when demand is highest means less reliance on fossil fuels and lower carbon emissions too. A stable grid means a better energy system – less chance of power cuts and ‘brown outs’ – temporary reductions in voltage in the grid which can lead to things like dimmed lights.
And it’s not only the grid that gets the benefits of V2G – in the future EV drivers will be able to benefit by selling their EV electricity back to the grid, or earning credits. V2G is very new, with only a few cars and chargers currently compatible, but it could be the direction that the industry is heading. So join us as we get up to speed on V2G technology in more detail below.
How does vehicle-to-grid technology work?
It helps to think of EV batteries as mobile energy storage when thinking about V2G technology. Connecting these storage assets stabilises the grid, can help us make the most of renewable electricity sources, and reduces our dependence on dirtier forms of energy like oil and gas.
When electricity supply can’t keep up with demand, the batteries in connected EVs can discharge power back into the grid in real-time. When there’s an excess of electricity, EV batteries can charge up.
There are a range of reasons for why the electricity supply may be over or under-delivering. It might be as simple as more people needing to use power at certain times. But it can also be caused by our transition to renewable energy sources, like wind and solar. After all, we can never quite guarantee when the wind will blow or the sun will shine.
Some of the biggest demand surges in recent times have been during sports events – during the Euro 2020 football final between England and Italy, an extra 1.8MW demand was placed on the grid - equivalent to 720,000 boiling kettles.1 A nationwide fleet of plugged in, V2G compatible EVs, would have been just the ticket to help the grid with such a boost in demand!
Beneath it all though, V2G is underpinned by smart software and the latest in EV charging kit. First, V2G technology relies on bi-directional EV chargers that allow electricity to flow back and forth between the grid and an EV battery. This is unlike most EV charger models that only allow a one-way flow of electricity.
To get a little technical, bi-directional chargers convert alternating current (AC) from the grid into direct current (DC) for charging, and conversely, convert DC from the battery back into AC to supply the grid.
As well as bi-directional chargers, V2G technology uses software to communicate between the EV, charging station, and the grid. This software monitors electricity demand and manages the flow of electricity to ensure it’s optimised for the grid’s needs and the EV’s battery health and charging level.
For example, if an EV is plugged into a V2G EV charger when electricity demand is low, it’s likely that the software will charge the EV’s battery. On the other hand, when electricity demand is high, the software will discharge stored electricity from the EV’s battery to the grid.
Don’t worry though, there’ll always be the option to prioritise your charging needs so your car’s fully charged when you need it. You’ll also be able to override V2G functionality and scheduling too in case you need to charge unexpectedly.
What are the benefits of vehicle-to-grid technology?
Balancing and stabilising the grid.
With a nationwide fleet of EV owners willing and flexible enough to adopt V2G technology, the grid could be much more stable. This would help smooth out fluctuations in electricity supply from the grid. As the UK brings more renewable but less predictable sources like wind and solar online, this could be especially useful.
Helping EV owners harness their batteries to earn cheaper charging or rewards.
While it’s still early days for V2G technology, with a limited number of compatible cars and chargers, it does hold potential for EV owners in the future. With a compatible car and charger, an EV owner can help offset their motoring costs by earning money or cheaper charging rates when they agree to send electricity from their EV battery back to the grid.
Supporting a cleaner energy ecosystem.
During peak times when there’s lots of demand for energy, the grid needs to fall back on fossil fuels to power the UK’s homes. Clearly, this isn’t great for the UK’s energy transition.
V2G however, paves the way for EV owners to charge their cars with off-peak electricity powered by renewables, and then send this electricity back to the grid at peak times. This means that more and more homes could run on renewable electricity if V2G is widely adopted.
How far along the road is the UK in adopting vehicle-to-grid technology?
Are there any government policies and incentives in place to encourage vehicle-to-grid?
Along with broad support for the EV charging infrastructure nationwide, the UK government supports V2G charging through initiatives such as the electric vehicle smart charging action plan. Part of this plan is the Vehicle-to-X Innovation Programme which aims to remove barriers to the wide-scale rollout of V2G by the end of 2025 in two main ways. First to fund projects that look to lower the cost of V2G chargepoints, and second, to increase the number of compatible EVs.
The Vehicle-to-X Innovation programme covered other ‘vehicle-to’ technologies too, including vehicle-to-load (turning your car into a battery bank), and vehicle-to-everything, or V2X, which aims to connect EVs with everything around them.
The government is working with Ofgem and the energy sector to put in place the right market conditions and regulations for V2G. Ofgem is also collaborating with Distribution Network Operators (DNOs) too – the companies responsible for getting electricity from the grid to your home or business through local power lines and cables. DNOs are critical in making sure that connections between V2G chargers and the grid work smoothly.
At present though, there aren’t any specific customer-focused incentives available to encourage potential EV buyers to choose V2G compatible cars over others.
Have there been any pilots for V2G in the UK?
Yes, the UK has been a leader in V2G trials. Project Sciurus, which ran in 2021, brought together partners including Kaluza, Nissan, Cenex and Innovate UK. It was the world’s largest domestic V2G trial with over 300 chargers supplied and installed, at no cost to the customer.
The goal of the trial was to see if home V2G charging can make the grid more flexible and help EV drivers save on their electricity bills. The results were impressive – the trial found that EV drivers could save up to £725 on their electricity bills! 2
Vehicle-to-grid charging and your EV.
Is my EV compatible with vehicle-to-grid charging?
Currently only a few EV models are compatible with V2G. Some auto industry publications keep track of compatible car models, so you can keep an eye on those, or check with the manufacturer of any EV you might be considering. The same applies to chargers – it’s best to check with the manufacturer to confirm whether a specific model is bi-directional and supports V2G.
Which cars and chargers are compatible?
At the time of writing, it’s still early days for V2G technology in the UK with only a small number of V2G-capable chargers and cars. The Wallbox Quasar is probably the most well-known compatible bi-directional charger. In terms of EVs, the Nissan Leaf and Kia EV9, Volkswagen ID models, the Audi Q4 e-tron, and Polestar models are the most prominent compatible cars.
Is vehicle-to-grid charging safe for EV batteries and will it affect lifespan?
If you use vehicle-to-grid (V2G) it will increase how often your EV battery is charged and discharged. Over time, this extra use can wear the battery down a bit faster. How much faster the battery wears down depends on things like how deeply it's discharged each time, how quickly it's charged or discharged, and the temperature.
However, clever technology is helping to keep this wear to a minimum. Smart battery management systems keep a close eye on the battery, and software can control charging to minimise stress. So there might be a small reduction in battery life, but technology is improving to reduce the impact.