Vehicle to grid UK (V2G): When can my EV power my home?

What are the benefits of V2X?

In theory, V2X enables you to do anything a home battery can do. Currently, your EV can only charge from the grid but cannot export power. You might have a smart tariff or solar panels, which already allow you to charge your EV cheaply. With V2X technology, you would be able to do three key things with this power, just like with a home battery: First, you could power your home from your car. Second, you could export power when it is most expensive. Third, you could supply your car battery to help stabilise the grid and earn handsome rewards along the way.

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Whether V2X is a substitute for a home battery depends on the use case. In essence, if your car is at home most of the time, V2X technology could replace a home battery. If it is not, then it doesn’t. For example, if you want to store excess solar power in your car to use later, the car would need to be plugged in while the sun is shining.

Is V2X readily available in the UK?

The short answer is no. Currently you can only do it with select car models and by sourcing expensive specialised charging equipment from abroad.

For V2X technology to work, 3 elements need to be in place:

• A compatible car
• A compatible charger
• A permission from the grid operator

There currently only 3 V2X-enabled car models available in the UK. From a technical perspective, a much wider range of models would be able to perform Vehicle to grid and you will find some longer lists online. However, as of November 2024, it is allowed by manufacturers for only the following models:

• Nissan LEAF
• Nissan e-NV200
• Kia EV9

However, there are no chargers ready to buy – or only at a prohibitive price point. Wallbox, Indra, and Solaredge have all announced V2X-ready chargers, but it is impossible to buy these products in the UK. Even outside the UK there are two caveats for available systems: First, they are very expensive, costing several thousand pounds – and oftentimes more than a home battery. Second, most available chargers only support CHAdeMo connectors rather than the more common CCS standard.

Permission, on the other hand, is possible to obtain. In the UK, V2G chargers are treated just like any other storage system. In practice this means, you will either need a G98 or G99 approval, which is a standard process.

Interestingly, Octopus has launched a dedicated V2X tariff called “Power Pack” recently. However, they also conceded on their website that it only works with very few models and that there are no compatible chargers for sale in the UK currently.

What are the barriers to vehicle to grid adoption?

Vehicle to grid has been in the making since years. Several V2G trials were conducted in the UK in between 2018 and 2022 by companies including Octopus and OVO. A couple hundred customers participated in the programs. So why is it still not commonplace? There are three main reasons:

First, many automotive manufacturers have cited battery degradation as the main reason for not offering V2G capabilities. Range is one of the key purchasing criteria for EVs and automotive manufacturers will do everything they can to not disappoint their customers in that dimension. However, each additional charge/discharge cycle reduces the battery's lifetime and, consequently, the vehicle's range. This has especially been the case for so-called “NMC” technology, which has been the technology of choice for many EVs, especially in the high-performance segment. NMC is particularly strong in terms of performance and energy density. However, the main drawback is that it has a lifetime of only around 3,000 cycles, compared to about 6,000 cycles to its main competitor “LFP” technology. Recently, many automotive manufacturers, especially in the non-premium segment, have switched towards LFP technology as the performance gap between the two technologies has been decreasing. If you own an Audi, BMW or Porsche EV, you will have NMC batteries. If you own a Chinese EV, it will likely have LFP batteries. For Tesla drivers it is uncertain, as it depends on which factory your EV was produced in. Lastly, it is to remark that there has been a study which indicates that, if done well, V2G does not degrade batteries.

Second, large-scale V2G adoption requires common standards. They are needed to facilitate the two-way data exchange between the vehicle, charging system and grid that is required to quickly identify and authenticate the vehicle, provide automated billing, enable load management, and offer digital certification for enhanced security. To date, such standards have not been adopted. There is a common standard called ISO 15118-20. However, few automotive manufacturers have adopted it, given that it is not mandatory in the UK.

Third, vehicle to grid adds contractual complexities. There are two main elements to this: First, it has direct implications on leasing and warranty conditions. If you are on a leasing contract, you will most certainly have an annual mileage specified in your contract. However, V2G essentially degrades the single most expensive piece of your car without showing up in that metric. V2G might therefore violate leasing or warranty conditions of your car. Second, billing will become more complex. Imagine your employer provides you with a company car. You will typically charge the car overnight at home at a cheap overnight tariff. With V2G capability, it would be optimal to discharge the car during the day at peak-hours when it will be plugged at your employer’s site. This raises the question who pays for charge and who reaps the benefit for the discharge.

When will V2G come in the UK?

The timeline remains uncertain. There is currently no legislation in place which prescribes a V2G scale-up in the UK. Before the government does so, adoption barriers will remain, and it is not unlikely that automotive manufacturers will continue to stand in the way. At this stage it’s worth keeping an eye out for V2G but don’t wait for it!

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