Using the electricity stored in an Electric Vehicle battery to smooth and manage demand on the electricity grid was a big topic at this year’s Low Carbon Vehicles exhibition and conference in September at the Millbrook proving ground.

This Vehicle to Grid idea is both simple and attractive.

As we drive towards a zero-carbon economy, two forces demand changes to our electricity grids. We will see a rapid rise in the number of electric vehicles on the road and a dramatic increase in the percentage of our electricity supply that comes from renewables.

What’s the problem?

By 2040 electric vehicles will account for 5% of the total global electricity demand. The UK alone will need between 5 GW and 18 GW of additional peak demand to charge electric vehicles. Strengthening our electricity network to handle that demand would cost £17 billion by 2050. Decarbonising road transportation is essential to meet our zero-carbon targets, but it means big changes to the electricity supply system.

The percentage of electricity from renewables is rising at the same time as we decarbonise generation. Renewables are intermittent, so we need ways to store excess energy when it is abundant and release it when demand exceeds supply. Demand peaks in the evenings when everyone returns from work, starts cooking and turns on the lights and entertainment systems. Any electric vehicles used for commuting will get plugged in at the same time, putting even more stress on the network.

So what is vehicle to grid technology?

Graph showing electricity demand through the day, with and without V2G
Electricity demand with and without V2G

This is where Vehicle to Grid (V2G) comes in. It is a deceptively simple idea. We need more grid-connected storage to smooth out the peaks and electricity demand and to balance the intermittency of renewables. And we are predicting a future where lots of partially charged, large capacity batteries are connected to the grid. If we can pull electricity from those batteries at times of peak demand, and recharge them when we have excess supply and electricity is cheap, we can smooth out the peaks, stabilise the grid and cut the cost of charging.

It is a deceptively simple idea, but it will not be easy to implement. We did not design our grid to operate with millions of users who both demand and supply electricity. Every EV charger will have to be smart, bidirectional, and capable of linking to the grid so we can manage charging and discharging of the battery. These smart V2G chargers are around £6000 each at the moment, but costs will fall as technology improves and the numbers in use increase.

What is in it for me?

It is both a technology problem and a business model problem. There needs to be an attractive consumer proposition. What benefits will I receive? Perhaps payments for electricity I contribute to the grid at peak times, or cheaper charging. Whatever benefits I’m being offered, I will want to know that my vehicle is charged and ready to go when I need it. There is no point in receiving a fee for helping to stabilise the grid if my battery doesn’t have enough juice when I need it in the morning.

Fleet operators will look for a solid business case. If I invest in smart V2G chargers, what returns will I make?

The other player with a real interest in V2G technology is the electricity companies, particularly the Distribution System Operators (DSO’s). These are the people who deal with local areas of the National Grid and need to manage an increasingly complex mix of generators and users while keeping everything stable and within specification. Local parts of the grid may have equipment and capacity constraints that mean using V2G avoids expensive upgrading of the system.

Two recent reports have looked at the value that V2G technology could generate, who would benefit and how to distribute any income streams [1,2].

Real-life demonstration

Electric vehicle recharging
Powerloop Project – Octopus Energy

The technology is still in its early stages. Most of the activity is in R&D and demonstration projects. The V2G Hub notes 66 live projects around the world; over half in Europe. The UK Government is making a significant investment supporting 21 projects with a total value of £46 million.

The largest of these is project Sciurus led by OVO Energy. This will install 1000 V2G chargers with domestic customers testing both the technology and the business model. Project Powerloop will install 135 domestic systems and will trial a system that allows the user to specify when they need the car to ready to use through a smartphone app. Octopus Electric Vehicles are running this experiment.

In the business market the E4Future project will see Nissan and partners deliver 1000 V2G chargers to commercial users.

Electric vehicles will become part of the national grid

Using electric vehicle batteries as part of the electricity grid will happen. Growing numbers of electric vehicles and increased renewables in our electricity supply will demand it. The technology is there, but we need to create a viable business case and present a compelling consumer argument for large-scale adoption.

As is often the case with innovation, technology is not the problem. We can make it work; now we need to make it desirable.

Will Your Automobile be Part of the National Grid?
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