Ask the Experts: Where is the energy to fill EV batteries coming from?

We take your questions and put them to the experts….

By Will Dron on March 10, 2011 3:23 PM

We take your questions and put them to the experts… has only existed for just over a week but we’ve already been inundated with questions about EVs. One of the first we’ve been asked, and one that is a burning issue for the future of the electric car, is about power generation.

Matt Edwards, in a comment on James Allen on EV: My journey into electric motoring, asks:

“Where is the energy to fill the batteries coming from? This is not a simple question that can be fobbed off with mumbling about solar and wind – the requirements to power even a portion of the fleet are massive.”

The question is really in two parts:

1. What mix of energy do we get (and how clean is it)?

2. Can the grid cope with the expected electricity demand resulting from uptake of electric vehicles?

Where does our energy come from?

In pursuit of the answers, we got hold of the Department of Energy and Climate Change and energy provider British Gas, but the first point to make is that different countries have different energy mixes, and different regions within the countries can vary too.

In America and Japan, for instance fossil fuels form a higher proportion of the mix than in the UK. According to the US Energy Information Administration and Japan’s Agency for Natural Resources and Energy, 83 to 84 per cent of their national energy comes from a combination of coal, natural gas, crude oil and natural gas plant liquids. Nuclear forms roughly nine per cent while renewable energy accounts for between seven and eight per cent.

The UK power mix at present is a little different. Figures provided by the DECC show Nuclear has a much larger role to play, with a 15 per cent share of the pie. Renewable energy, thanks in no small part to our offshore wind farms, is slightly higher than our US and Japanese counterparts at nine per cent, but fossil fuels are still the staple of our energy mix at 76 per cent.

As outlined in our story on the Government’s recent Carbon Plan, the UK is having to reduce carbon emissions by 80 per cent by 2050 so we can expect to see a move away from fossil fuels towards renewables and nuclear, and electric vehicles will be a vital part of the solution.

So will the grid be able to cope with an increase in electric vehicles?

In short, not under the current energy mix… but this actually more complex than just looking at the effect of electric cars.

According the DECC, coinciding with a need to reduce carbon emissions is the very real prospect of total electricity demand doubling by 2050. The increase in numbers of EVs will be just a part of this increase.

To meet the demands, we’ll see a raft of new, more efficient technologies entering our home. Smart appliances, for instance, will be designed to work at off-peak energy periods.

But more significant is that we will see the Government incentivising a shift to home energy generation in tandem with the cleaner centralised power mix. Domestic solar panels will become more prevalent, with uptake given a helping hand via the Government’s Feed-in Tarrif, which allows solar panel owners to earn revenue by feeding unused electricity back into the grid.

With Government help, we could also see fuel cell boilers begin to appear, which generate renewable electricity as well as gas for the home (see Honda’s example here).

So does that worry the energy big boys? Well, no, not really. They’ll simply find ways to adapt.

“We see a big shift for us as a company in not just selling units of gas and electricity but helping customers use less,” says British Gas media relations manager Elliott Grady.

“This may sound counter intuitive but it opens up new low carbon markets for us as a seller of energy efficiency products and microgeneration (solar panels etc). It’s good for us as a business and also good for customers and the climate change agenda.”

As reported by, British Gas expects 700,000 UK homes to have solar panels by 2020.

So does that mean the system will be able to cope? Well, again it gets complicated.

“The electricity grid was never designed to cope with these new technologies – the added strain on the system that comes with EVs and the two way nature of selling solar power generated energy back to the grid,” says Grady.

But don’t fear… steps are being taken to ensure we don’t suffer an energy implosion.

“Ofgem has set up a fund called the Low Carbon Network Fund to look at these issues (£500m over five years),” continues Grady, “which enables Distribution Network Companies to work with suppliers and other partners to test new technologies on the grid.

“Over a three-year period, CE Electric and its partners will be trialling ‘smart grid’ solutions on the higher voltage networks within the electricity grid as well as creating clusters of smart-enabled homes to give customers more control over the way they use and generate electricity.

“The results will help the network companies make sure the electricity networks can handle the mass introduction of solar panels, electric cars and other greener technology.”

These ‘smart grids’ will essentially be an intelligent link between electricity generators and consumers, allowing networks to integrate the actions of both in order to efficiently deliver sustainable, economic and secure electricity supplies.

That’s all very well, but what happens if everyone decides to charge their cars at the same time?

When British Gas announced they’d be offering a service to install EV charging points in the homes of Nissan Leaf owners, they supplied research that suggested 10 per cent of UK households could own an electric car by 2020. That equates to 260,000 homes and is one of the most optimistic estimates we’ve seen.

Given that that’s an awful lot of people charging up, energy suppliers will want to avoid it happening at peak hours when the grid is already stretched. And so smart ‘time of use’ tariffs (a more sophisticated peak and off peak) will be introduced to help encourage people to avoid using energy at peak hours.

“Say that between 2am and 5am is the cheapest electricity period,” Grady explains, “This will encourage people to charge their cars then and not at half time of the World Cup final when everyone is putting the kettle on for a cup of tea (to use an extreme example).”

It’s going to be a complicated future, but it looks like the Government and energy companies are have anticipated a lot of the issues. The Government has said electric vehicles are vital to meeting our carbon emissions targets for 2050, but we will at the same time need to bring in drastic changes to the way we produce and consume energy for all our needs (not just to power EVs).