Vehicle-to-grid charging, explained

The energy market is evolving. From AI to digital technologies, automation to smart charging. And one idea, vehicle-to-grid (V2G) charging, is becoming more and more talked about.

Image credit: Kaluza Energy

What is V2G charging?

Vehicle-to-grid charging is a system in which electric vehicles (EVs), plug-in hybrids (PHEV) or another battery vehicle communicates with the National Grid and provides energy on demand.

V2G charging is a part of this new wave of technologies that are changing the energy market for the better. As your electric car’s battery has the ability to charge and discharge, it could sell any surplus electricity to the grid using a smart charger. 

At any given time, 90% of cars are parked and not in use. This provides the National Grid with an opportunity to source electricity at a fast response rate. Battery storage can react faster than any other source of energy connected to the National Grid (e.g. Hydropower, nuclear, coal, etc.).

Projections from the National Grid also state that there will be between 2.7-10.6 million EVs on the road by 2030. At present, they predict that around 220,000 EVs will provide V2G services in 2030 — more than the entire volume of plug-in cars in the UK at the end of 2018. 

V2G charging has the potential to play a significant part in our future energy system. If we could eventually get 5 million EVs participating in V2G charging, that would be the equivalent of 15 Hinkley Point C power stations.

For solar PV system owners, this means in the near future, you could store free electricity from your solar panels in your EV’s battery and then sell this to the National Grid for a profit. 

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Smart charging

Vehicle-to-grid charging is a type of smart charging. This is a form of electric vehicle charging that is more intelligent than manually switching the charger on and off. 

Smart charging allows you to control the times and rates at which an EV’s battery charges. This benefits both EV owners and the National Grid. By having varied times and rates of charging, the demand for electricity from the National Grid are reduced at peak times. It also encourages owners to charge off-peak when their energy supplier provides electricity at a lower unit price.

At Solar Plants, we offer several different branded EV chargers. For example, the Zappi EV charger is intelligent enough to charge only using usually exported energy from your solar PV system. The unit can also automatically charge exclusively at times when your smart tariff’s unit prices are at their lowest. 

Smart chargers offer fast, automatic charging. You can also control certain units via a smart device app. V2G is one type of smart charging, but it’s also a part of a bigger picture of how we’ll power the National Grid as the electrified economy expands. 

Energy suppliers

Energy suppliers also have a part to play when it comes to vehicle-to-grid charging. V2G charging will help diversify the UK’s fuel mix.

There are two main benefits of V2G charging:

1. You are not demanding energy from the grid during peak times.

          A. You can either charge your electric vehicle using your solar PV system or overnight using a smart tariff.

2. You are providing energy to the grid, for an income, when demand is high

          A. By selling surplus energy to the grid during peak times, you are helping reduce the population’s reliance on fossil fuels.

There are energy suppliers that have already begun trials with V2G charging. 

Octopus Energy

Octopus Energy is trialling V2G charging through their Powerloop bundle, one of the world’s first mass domestic V2G projects.

Customers with a Nissan LEAF have their homes fitted with a V2G charger. They switch to Octopus Energy’s Agile tariff, which is a smart tariff that’s unit rate changes every half hour with the wholesale cost of energy. The V2G charger then imports cheap energy to charge the EV and exports energy when prices are high. 

Octopus Energy has developed a smart device app. You control when you want to charge the car and when you want to export energy. You can set that the car’s capacity needs to be charged by 80% before 8:00 am, for example. 

If you’re a Solar Plants customer, you can have £50 credit on us when you switch to Octopus Energy.

OVO Energy

OVO Energy is also trialling V2G charging using the Nissan LEAF. OVO Energy explains that as renewable energy is intermittent by nature, we need to utilise battery storage to help create a flexible, balanced National Grid. 

Similar to Octopus Energy, you can tell the app when you need the car to be ready by and what it’s minimum charge level should be. Then when you’re home, just plug the car in. The smart charger will automatically decide when to charge your car and when to export energy. 

OVO Energy is also microgeneration ready. The company will pay you your import electricity unit rate + 2p for every solar unit (kWh) you export to the grid, as measured by your OVO smart meter.

Before you get your V2G charger installed, you will need to waive your Feed-In Tariff’s Export Tariff’s payments (your Generation Tariff will remain unaffected). For any kWh exported through the V2G charger, you will earn 3x what you would earn through your Export Tariff. 

Kaluza, through OVO Energy, is planning to install over 1,000 V2G chargers by the end of 2020.

As both Octopus Energy and OVO Energy are exclusively trialling this through the Nissan Leaf, the carmaker has stated that the Leaf’s battery warranty won’t be affected by the increase in cycles by V2G charging.


Vehicle-to-everything (V2X) is a similar concept to vehicle-to-grid charging. It is the same as V2G charging in that the focus is on how we can make technologies communicate with each other, and improve the way we live. 

V2X is a wireless technology aimed at enabling data exchanges between a vehicle and its surroundings. The main motivations for V2X are road safety, traffic efficiency, and energy savings.

V2X incorporates types of communications such as vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), vehicle-to-vehicle (V2V), vehicle-to-pedestrian (V2P), vehicle-to-device (V2D) and V2G. 

By sharing data, V2X communication systems improve driver awareness of upcoming potential dangers and dramatically improve collision avoidance, for example. 

V2X will enhance traffic efficiency by providing warnings for upcoming traffic congestion, proposing alternative routes and ensuring eco-friendly driving, by reducing CO2 emissions through adaptive cruise control and smarter transportation management.

If we continue to develop V2X, we could eventually see advancements such as wireless charging for electric vehicles. This could be a solution to the infrastructure issues which many believe is holding back the uptake of EVs. 

Many of us now live in densely populated areas, like cities, that don’t have off-road parking for our cars. If we can increase the amount of infrastructure available, such as simply installing more public EV chargers, we can reduce air pollution and reduce the transport sector’s carbon footprint.

Battery storage

Even though vehicle-to-grid charging is growing in popularity, and it will play an important part in our future fuel mix, there are alternatives. 

However, if you have an electric vehicle and solar PV system, the addition of battery storage can help you complete your self-sufficient dream. What happens:


1. Your solar panels power your home during the day

          A. Any surplus energy produced is diverted to charge your battery or car

2. In the evening, your battery powers your home and/or charges your car via a smart charger

3. If the battery is fully discharged, any remaining capacity of the EV’s battery can be charged by cheap electricity via a smart tariff


You can also earn through your energy supplier’s Smart Export Guarantee (SEG). This legislation was introduced by the UK Government to replace the now-gone Export Tariff, which was a part of the Feed-In Tariff scheme. 

SEG mandates energy suppliers with 150,000+ customers to pay for any exported solar energy. This is a great alternative because it means your EV’s battery has fewer cycles (i.e. a charge to discharge) so the battery capacity is less affected by use.

Social Energy

There is also the alternative of using a battery licensed by Social Energy. Solar Plants installs a number of different battery storage brands, including two Solax Triple Power batteries (4.5 and 6.3 kWh) that are licensed for use under the Social Energy scheme. 

Social Energy is like another utility company, in that they provide you with energy from the National Grid. However, they use AI to monitor your energy usage and patterns to monitor when there is surplus energy in your battery. 

Social Energy automatically charges and discharges your battery when energy demand is low and high from the National Grid, respectively. This means, alongside the free energy from your solar panels, you will purchase energy when cheap and sell it when expensive, meaning you earn more as well as save. 

Concerns of V2G

  • Implementation costs
    • Even though Octopus Energy and OVO Energy are offering free installation during their trials, the costs could be significantly more than a traditional smart charger when commercially available
  • Possible increased battery degradation
    • Due to the increase of cycles, your EV’s battery could be used up more quickly thus decreasing the capacity

Don’t want to wait for V2G to boost your income?


Future of energy

Vehicle-to-grid charging has a big part to play. As the sources of our energy shift from fossil fuels to renewables, we will need to become more flexible with our energy usage. V2G provides this as it encourages electric vehicle owners to sell energy at peak times and buy it at off-peak times. 

The future of energy is also affecting business. Businesses are being encouraged to go greener but there is also a wave of new innovative start-ups that are replicating Netflix and Uber type business models. 

For example, carsharing businesses are growing in popularity. We Drive Solar, in the Netherlands, allows customers to subscribe to the service and reserve any of the electric vehicles that are registered on the system. The customer can borrow the EV for however long and then park it back up to charge for the next customer. 

We Drive Solar is exploring the idea of V2G charging because they understand that cars spend more time parked up than being driven. This means the business can earn an income even when the vehicles are parked up, because they’re selling surplus electricity to the grid.

This still means we should move towards more decentralised grids, so we can limit the distance energy has to travel down the National Grid. This means more renewable microgenerators, more regional renewable systems and a larger adoption of battery storage. We would be increasing efficiency, increasing reliability; reducing fossil fuels and reducing costs. 

Battery storage also helps the National Grid become more flexible by storing renewable energy for use when the wind isn’t blowing or the sun isn’t shining. It has never been more economical than now for a homeowner with solar PV to retrofit a battery. 

And as the government sets targets for more low carbon heating, our electrified economy is going to continue to expand. This means it is vital that the residential solar PV market continues to play a part in the future of our energy, to benefit both consumers and the National Grid.

The demand for energy will likely mean an increase in energy prices. By installing a solar PV system at your home or business, you can protect yourself and become more self-sufficient.


Power your home and car with free, green energy produced by your solar panels.

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