From Charging to Sharing: What You Need to Know About V2G in 2025

First introduced in the early 2000s as a way to provide stability and resilience to the electric grid, Vehicle-to-Grid technology has come a long way. Leading EV manufacturers are now introducing V2G-prepared cars. While it holds promise for contributing to the stability of the electrical grid, it is still in the process of being fully developed and made ready for widespread use.

In this article, we will explore what all the fuss around V2G is about and how much progress is still needed before regular EV owners can try it out.

Vehicle-to-Grid, or short V2G, is a technology that enables electric vehicles to send power stored in their batteries back to the power grid. It has been developed to help balance energy production and consumption.

Vehicle-to-grid is one of several cases of so-called bidirectional charging. All in all, there are three main cases:

• Vehicle-to-Grid (V2G): Supplying energy to the grid.

• Vehicle-to-Home (V2H): Powering a home with electric vehicle battery energy (e.g. during a power cut).

• Vehicle-to-Load (V2L): Powering external devices (e.g., a coffee machine when camping) from an electric vehicle.

V2G basically turns electric vehicles into mobile energy storage units. But it’s not just about supporting the grid. Car owners using this technology can potentially earn money by feeding excess energy back. This possibility makes V2G both attractive and incredibly complicated.

The idea behind V2G is that electric vehicles collect power (charge) when the demand is low. Then, during peak demand hours, they send the power from their batteries back to the public power grid. The charging station communicates with the grid service provider to determine energy needs and manages the flow of electricity between the EV and the grid.

For example, as people return home from work, they increase the power of air conditioners that were previously set to a minimum, turn on computers to play VR games requiring a lot of energy, and activate other devices that had been in standby mode, waiting for their owners to use them. As a result, the grid operator experiences high loads and is interested in buying electricity stored in EV batteries.

During off-peak hours, such as at night, when there is excess energy, cars can recharge. The goal of bidirectional EV charging, in this case, is to contribute to grid stability and reduce the need for additional power plants.

If V2G technology were pure bliss, its development would advance more quickly. One concern is that frequent use could accelerate battery wear. In addition, the infrastructure needed is also costly, and financial rewards for owners aren't always clear. Overuse of V2G could also overwhelm a grid and the payment systems that are not yet prepared.

Let’s look at this in a bit more detail.

Some are worried that frequent charging and discharging cycles can accelerate battery wear. Accordingly, this could reduce its lifespan and lead to higher replacement costs. But not everyone agrees.

First, a discharge rate of 3 kW, which is assumed to be the case for bidirectional charging, is not likely to have any impact on the battery. AC home charging, in general, is not harmful, as it is done at low power. And V2G is essentially just more of the same as it involves using home charging technology for bidirectional charging.

Additionally, some vehicle manufacturers already take extra precautions. For instance, Volkswagen restricts some of its electric models to a minimum battery charge of 20% during DC bidirectional charging. This ensures you’re always ready for a spontaneous trip while also  minimising the possibility of harming the battery.

As we mentioned earlier, implementing V2G technology can decrease the demand for new power plants. However, widespread adoption requires costly and time-consuming upgrades to the grid, charging infrastructure, and vehicle electronics to handle large-scale power exchanges efficiently.

The potential to earn income by feeding energy back to the grid is certainly appealing. However, no one can currently promise that the actual compensation will be sufficient to justify the potential battery wear or installation costs.

Some complicated situations may prevent people from seeing V2G as particularly advantageous. For example, if you charge your car battery at 15 cents/kWh and then leave it in the garage, not needing it until the next morning, the grid operator might buy it from you for just 5 cents/kWh, as there is currently no system for negotiating the price.

On top of that, even though you may not need the energy right now, your battery is still in use, and may not be charged when you need it. The thing is that if you set your battery's state of charge high, say 70%, you’ll always have enough energy for the next day, but your financial returns will be lower since not much energy can be shared with the grid. Set it too low and you might wake up to an empty battery when you really need it. Will the financial returns be worth it? That’s questionable.

The main requirements for V2G to be market-ready are: standardising ISO 15118 for successful communication; bringing more compatible vehicles and bidirectional charging stations to the market; addressing grid and regulatory issues; and offering affordable solutions.

The international ISO 15118 standard is key to V2G. It aims to enable communication between vehicles and charging infrastructure. While ISO 15118-20 for DC charging is standardised, AC charging is still under development.

Multiple legal and economic structures for V2G are still being developed. Some countries, like France, already have clear regulations. Others, like Austria, are slower with introducing suitable policies, addressing tax issues, and creating financial incentives for V2G to be accepted.

The motivation to adopt V2G varies depending on the country’s energy mix and its impact on grid stability and consumer remuneration. In Germany, dominated by such renewable energy sources as solar or wind power, consumers can earn more from V2G by storing excess clean energy and helping to manage peak loads. In contrast, countries rich in hydropower, such as Austria, offer fewer incentives because hydropower is fairly flexible, with minimal supply fluctuations. Countries with a more traditional energy mix, like Poland, can offer moderate rewards for peak management. The last scenario is the same for France, but the country is leading with the development of bidirectional charging as it is deeply committed to energy transition and sustainability goals. Furthermore, France has a well-established and rapidly growing EV market, which provides a large base for testing and rolling out bidirectional charging technology.

While focusing on how to bring V2G to the market, it shouldn’t be forgotten to ensure EV owners are interested in using it. For instance, they should clearly understand that their energy bills will be reduced if that’s really going to be the case. On top of that, more electric vehicle manufacturers should openly address concerns about battery lifespan and any possible changes to the warranty conditions. 

Of course, the technology can be market-ready before these issues are resolved, but can this actually be defined as “ready”?

To perform V2G, wallboxes and chargers should have advanced Vehicle-to-Everything (V2X)-ready hardware. Some DC chargers are already there, though they are really costly. AC wallbox manufacturers like go-e are bringing products with compatible hardware such as our go-e Charger PRO to the market. However, software for real-time energy exchange and billing is not ready for companies to implement it, as the aforementioned issues still need to be resolved before the software can be finalised.

Yes, there are wallboxes with hardware that supports V2G. However, the overall system required for V2G functionality is not yet ready for widespread use. This means that while such wallboxes exist, they are not accessible for regular use with V2G at this time.

Most V2G-ready chargers are DC. Unlike AC chargers, which rely on the car to convert AC to DC, DC chargers do the conversion themselves. This means V2G could be activated via software in the car, without extra components. While the software for V2G is still being developed, DC chargers are closer to fully supporting it.

Some AC wallboxes, like the go-e Charger PRO, openWB Pro, and SolarEdge Ladestation, are expected to support V2G as the technology advances. For V2G to work with AC charging, the car must have a special bidirectional onboard charger to send power back to the grid. Since most cars don’t yet have this feature, AC chargers don’t currently support V2G.

Once more vehicles support the ISO 15118 standard and the V2G software is finalised, bidirectional charging will become a reality.

Some electric cars are prepared for V2G but since the standards are not yet finalised, the technology cannot yet be used due to issues such as the incomplete development of the AC charging standard (ISO 15118-20), the lack of compatible software for real-time energy exchange and billing, and ongoing regulatory and market framework development.

Electric cars such as the Nissan Leaf, Volvo EX90, Cupra Born, and Polestar 3 are V2G-ready. Popular Volkswagen models such as ID.3 , ID.4 , ID.5 and ID Buzz are prepared for bidirectional energy flows as well. In addition, vehicles of the next generation of the Genesis Electrified G80 / GV70 are expected to be V2G-ready.

• The benefits of V2G are that EVs act as mobile energy storage units. Owners can potentially earn money by feeding excess energy back to the grid. Plus, it can help to reduce the need for additional power plants and contribute to grid stability.

• The downsides of V2G include potential battery wear from frequent charging and discharging, expensive technology upgrades, and uncertain financial incentives. The rewards may not offset the costs.

• While chargers with V2G-compatible hardware are available, the necessary infrastructure for this type of bidirectional operation is not yet fully developed. As a result, the wallboxes cannot currently be used for regular V2G applications.

At the moment, there are quite a few challenges to overcome for the Vehicle-to-Grid charging to become a reality. Starting with creating effective regulations and implementing the technology, and followed by creating true customer value. In the meantime, a model developed by the Research Center for Energy Economics in Munich states that by 2030 more than a third of all electric vehicles on the market should be used bidirectionally, including the V2G type of charging.