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What’s the deal with V2G, or vehicle-to-grid?

Published by on 04.08.2019 - 5 min

What if electric cars became a pillar of the electricity grid? That’s the idea behind V2G, or vehicle-to-grid, a technology that makes charging a two-way exchange, allowing cars to return part of the electricity stored in their batteries to the grid in order to optimise its operation and alleviate the intermittent availability of renewable energy sources.

Energy transition puts energy suppliers in front of a double challenge. On the one hand, they need to be able to harness intermittent energy sources like wind and solar to an ever-increasing degree, but without being able to store the energy they produce at a large scale. On the other hand, they need to be able to guarantee the stability of the grid and to instantly meet consumer demand.

How does V2G work?

That’s the context in which vehicle-to-grid (V2G) technologies come into play.  They see an electric car’s battery as an extension of the electrical grid, as an energy reserve that electricity suppliers can draw from on occasion.

Charging becomes a bidirectional process, meaning the network no longer simply supplies the vehicle’s battery with electricity: it also considers this battery as a power source to be used to meet various energy consumption needs. With vehicle-to-grid, an electric vehicle user can therefore decide to store electricity when rates are the lowest, then use it when the price goes up.
Operation of vehicle-to-grid

The advantages of vehicle-to-grid

A driver who returns home at night could, for example, use the energy stored in his electric car’s battery to power his household appliances. He can then recharge that same battery later in the evening, at the time when the electricity supplier offers the cheapest rates.

In the same way, the flexibility provided by V2G means that a battery can be charged during the hours that energy is being produced by renewable sources, and then that electricity can be used when solar or wind power is unavailable.

That’s also the principle behind stationary energy battery storage systems, which aim to give batteries a second life by creating electricity reserves at the scale of a house or charging station.  

How V2G supports the electrical grid

At the level of the entire network, the grid energy storage capacity made available by V2G helps operators handle fluctuations in demand more effectively. It can help absorb a peak in consumption, for example, without relying on a selective power cut, or it can compensate for the micro-disturbances that might occur when energy production switches from one source to another.
As part of this model, operators pay customers who make their batteries available: V2G thus helps the end consumer reduce their energy costs.

Even smarter charging

Finally, vehicle-to-grid is also a key component in the creation of an intelligent distribution network, known as a smart grid, in which energy flows are constantly being optimised thanks to the monitoring that occurs at each step of the way.

Combined with the technical capabilities of electric cars, the smart grid mindset has already allowed islands like Porto Santo and Belle-Île-en-Mer to take very concrete steps toward the path of energy transition.


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