Vehicle-to-Grid is an exciting new technology which allows for plug-in electric vehicles to return some of their stored energy back to the grid. This "bi-directional charging" allows a nation's fleet of electric vehicles to act as a huge battery to support the power network.
Electric vehicles have sizable batteries, and there will potentially be a large number of them on the roads. The UK currently has over 30 million licensed cars, and on average each one spends an incredible 96% of its lifetime parked, with most of that time being at home. If the entire UK fleet were battery-electric today, with each vehicle having a 40kWh battery pack - that would amount to a staggering 1.2 terawatts of stored energy - just in cars alone. So, the potential is quite significant as only a small portion of vehicles would be needed to feed electricity back to the grid to make a difference.
It's a technology that goes hand-in-hand with renewable energy generation to "iron out" the peaks in demand. In return for the electricity they provide, owners of electric vehicles can get paid, similar to feed-in-tariffs that are available with Solar panels.
Companies around the world are currently testing Vehicle-to-Grid, with many energy companies trialling new V2G products to understand customer behaviour better and the effects of V2G on both the vehicle and the grid.
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What cars can be used for Vehicle-to-Grid?
The EV charging technology, CHAdeMO is currently the only one to support Vehicle-to-Grid. In the UK, only Nissan provides CHAdeMO charging on their Battery Electric Vehicles. As a result, the Nissan Leaf and Nissan e-NV200 are the only vehicles which support Vehicle-to-Grid in the UK at present.
CCS, which is a popular and competing technology to CHAdeMO in the UK, is currently working on a Vehicle-to-Grid standard.
Does it have any effect on the battery of the vehicle?
All batteries degrade over time and so the more cycles a battery completes, the further it will degrade. However, whilst discharging a battery to the grid is steady and constant; discharging a vehicle's battery through driving is as irregular as the terrain, roads and driving style. The exact impact on battery degradation through discharging to the grid isn't yet fully known, which is another reason that the trials taking place are helpful. A two-year study by the University of Warwick in 2017 discovered that it was even possible to increase the longevity of Lithium-Ion batteries over conventional charging and discharging through driving.
Other types of Vehicle-to-Grid
This technology also exists in simpler forms, such as local Vehicle-to-Home (V2H) and Vehicle-to-Building (V2B) where energy stored in connected vehicles can be used to power the home or buildings; which can be helpful for power outages or even as storage for local power generation such as solar.
Article last updated on October 30th 2020.