What is vehicle-to-grid (V2G) charging?
Vehicle-to-grid (V2G) charging is one of the most significant future developments for electric-car owners. Essentially, it will let them sell electricity stored in their cars' batteries back to the National Grid during times of high demand, potentially making money in the process.
Cheaper energy tariffs during late-night, off-peak hours allow electric-car owners to top up their cars for less than would otherwise be the case. Through the use of 'smart' software and charging points, the transfer of electricity back and forth from the car to the grid can be automatically controlled, ensuring the owner still gets their car charged as much as they wanted, in addition to feeding power back to the grid.
The technology is already being trialled and government bodies such as the Department for Transport are backing it, so before long V2G will become a reality.
How V2G charging works
V2G is based on using electric-car batteries as energy storage devices and being able to both add and take power from them while a car is plugged into a home wallbox chargers or public charging station.
New technology allowing cars' batteries to discharge back into the grid is needed in order for V2G to work as envisaged. Energy providers will incentivise customers with a small fee per kWh of electricity returned to the grid. The price difference between that fee and the cost of recharging your electric car during off-peak hours would be the profit made from V2G charging.
When will V2G charging be available in the UK?
Nissan and energy supplier OVO have run a 1,000-unit V2G charging trial in the UK. Participation takes two years and it's currently open to Nissan Leaf-driving OVO customers only, but the company estimates a £305 annual energy bill saving for users.
At the same time, the UK Government has pledged £30 million in funding towards V2G charging. The funding is split across 21 different projects, to pay for “research and design and development, with the aim of exploring and trialling both the technology itself and commercial opportunities.” The Government is also working on a separate trial in Oxford using a fleet of 100 vehicles with V2G charging technology.