Jumper cables attached to a car battery. Against a white background. Source iStock.

+ Creating a market for used batteries would help to reduce cost barriers to electric vehicle uptake.

While writing a report for a client, I recently took a close look at how the capital cost of electric vehicles (EVs) poses a barrier to their wider uptake. With batteries the biggest element of this capital cost, it’s obvious that creating a market for used EV batteries would help to reduce cost barriers. More than this, by recycling EV batteries as a buffer for personal renewable energy production we could make a paradigm change from consumers to producers.

Recent market studies suggest that the market for EV battery recycling could be worth £2 billion by as soon as 2016. However there are no clear strategies for how this market will be shaped. Indeed the question still remains to be answered whether it is better to recycle or reuse.

Currently, you might expect an electric car battery to carry between 18 and 70kWh in power and the price of the batteries is currently around £850 per kWh, dependent upon battery management systems and configuration. There are also theories abounding that batteries will reduce in capacity after around five or six years, and if so would need to be replaced if a car’s range is to be maintained.

These batteries would still have plenty of life left in them for other purposes. So what if we used the batteries we take out of EVs to store energy in our homes? The average UK household uses around 15kWh of electricity every day. So a reconfigured EV battery installed in a home could store enough energy to run the house for a day.

Rather than feed power generated by domestic PV solar panels into the grid, why not store this energy in the reconfigured EV battery to use yourself? Your PV panels could generate energy during the day while you’re out at work and the batteries could store it ready for use when you return in the evening.

A solution like this could ease pressure on our overstretched grid as our love of smart gadgets increases our demand for electricity. Stabilising the grid in times of high demand requires big buffer storage, or other contingency measures such as spinning reserve, that can be turned on quickly to boost generating capacity and stop frequency fluctuation. Banks of reconfigured EV batteries would be ideal for buffer storage in local communities – a block of flats might have its own substation-sized group of batteries, for example.

Indeed, a larger number of batteries could help us put more of the energy we generate into people’s homes. Let me explain, using wind farms as an example. Let’s say it costs around £1m per MW to connect an onshore wind farm to the grid, so as not to oversize the connection, farms are connected at their mean power. This means that when the wind blows hard and they’re generating more power than average, the extra power has to be shed and lost.

Buffer storage in the form of reconfigured EV batteries could store this power and feed it into the grid when the wind lessens. This solution could provide the holy grail for renewable energy – a storage and back-up facility for energy generated from our fickle weather!

I know people are looking into this issue, but I’m not aware that anyone has found a commercially viable end-of-life solution for EV batteries. When they do, it could be big news — not only for electric vehicles but also for the way we’ll use energy in the future.