What is V2G and bidirectional charging?

What exactly is V2G, and why is bidirectional charging a game-changer for the future of energy? In this article, we take a closer look at the technology and what it means for both EV owners and the energy grid.

A woman is about to smart charge her EV by plugging in the charging cable into her Zaptec charging unit at home.

What is V2G (Vehicle-to-Grid), also known as bidirectional charging for electric vehicles?

V2G stands for "Vehicle-to-Grid" and refers to the technology that allows electric vehicles to send energy back to the power grid. In other words, EVs, which traditionally only receive electricity, can also return power to the grid when needed. This is particularly useful during times of high electricity demand or when there is a shortage of renewable energy sources like solar or wind power.

How does V2G technology work?

V2G technology works through bidirectional charging, which allows electricity to flow in both directions. When the vehicle is charging, energy is stored in the car’s battery. When the car is connected to a V2G-compatible charger and the power grid requires more energy, part of this energy can be sent back to the grid. This helps stabilise the power supply and reduce the strain on the grid, especially during periods of high demand.

Through your driving preferences, your vehicle tells the charging station things like how much battery energy is available, what state of charge is required and when. These parameters are sent securely to your chosen vehicle-to-grid service provider, so they can trade any spare energy on your behalf. Your service provider could be your energy supplier, or perhaps another company (depending on how the electricity system is structured in your region). They will make sure your vehicle remains charged according to your preferences, and also send you any earned financial rewards. Of course, you can always opt out of the trading at any time. It’s a myth that enabling V2G will “allow people to drain your battery”; you’re always in control!

If you have ever wondered who can be a vehicle-to-grid service provider, the answer is anyone. It could be your energy provider or someone independent, depending on how the energy market is set up in the relevant country. The communication could be 4G, through your own Wi-Fi, or even the smart meter.

Why do we need a bidirectional/V2G-compatible EV charger?

A charging unit that supports bidirectional charging acts as a communication medium between the vehicle and the electricity grid. Without a charger that supports this technology, the car has no way to communicate with the electricity system. If you have a charger that supports the technology, the car will be able to "talk" to the charger, and the charger can accurately pass this information on to the electricity grid or service provider. The charger can then talk back to the car to explain what power needs to be exported and when. The charger handles accurate measurements and secure communications and ensures safety by intervening automatically if anything goes wrong.

4 benefits of bidirectional charging for electric vehicles

Reduced energy bills for your home:

Your electric vehicle can function as an energy store for your house. By using energy from your car during times when electricity prices are high, you can reduce your energy bills.

Reduced electricity bills with EV charging:

Instead of charging continuously, with V2G the charger can instantly switch from charging to discharging as grid conditions change. By dynamically taking advantage of cheap (or free) electricity – and avoiding expensive electricity in real time, you still get the charge you need, but at much lower cost.

Stabilisation of the power grid with V2G:

Bidirectional charging can help balance the load on the power grid, especially during periods of high demand. Many electricity companies will pay you for this service if you leave your car plugged in, which further reduces your energy costs

Increased use of renewable energy thanks to bidirectional charging:

By storing excess energy from solar panels or wind power in the car’s battery and releasing it when it’s needed, this makes sure there’s always somewhere to store renewable energy - so it never goes to waste.

The role of V2G technology in the future

V2G and bidirectional charging for electric vehicles represent the future of both transport and energy supply. As more households and businesses adopt electric vehicles and renewable energy sources, the need for smart energy management will increase. V2G technology can play a crucial role in the transition to a more sustainable energy system, where EVs are not just vehicles but also energy storage units.

Conclusion

V2G and bidirectional charging are forward-looking technologies that have the potential to revolutionise both the transport and energy industries. Whether you are an EV owner or simply curious about future energy solutions, it is worth keeping an eye on the development of V2G and bidirectional charging, as these technologies can change the way we both use and generate energy.