Prepare for the battery storage revolution

Solar panels on your roof might look sexy and advertise your green credentials to the neighbours but they aren’t much use if you’re not around during the day to use the electricity they produce. The solution is to install a high capacity battery to store the energy for use in the evenings when you really need it. The problem is that these batteries tend to be small, bulky and expensive and don’t store to much power in any event.

But battery storage does have a major role to play in our decarbonised energy future, according to Cormac Mannion, energy services manager with Energia. "Over the last few years a lot of people have started looking at microgeneration in their homes," he says. "The problem is that the electricity they don't use goes back to the grid and they are not getting the benefit of it. Microgeneration has really been for people who are engaged in the energy market or for new builds."

Batteries provide a partial solution. “A domestic battery will store between two and five kilowatt hours of electricity and is quite a big unit to store in your shed,” Mannion explains. “The average home uses 4,000kWh a year and about 12kWh every day so the battery is only going to meet some of its needs. But in a few years’ time you could have a battery 10 to 15 times its size sitting in the driveway. You may also see a situation arising where the electric vehicle manufacturers will take end of life batteries and recondition them for use in people’s homes.”

That is just the beginning. “We will also see the introduction of vehicle-to-grid technology where the car interacts with the grid to store electricity and supply it back when it is most needed,” says Mannion.

This would have the effect of turning the country’s electric vehicle fleet into a vast distributed battery which could help make the power grid more stable. “That is a way of getting more renewables on the system,” he says. “We have already worked with Eigrid on a pilot project to balance the grid using local level battery storage technology.”

There are also other more localised benefits. “You could even have a situation where autonomous vehicles would charge themselves and sell power to your neighbours on a peer-to-peer basis. This stuff is still in its infancy. Vehicle to grid is not being done in a big way at the moment but we are only seeing the tip of the iceberg in relation to the use of battery storage technology.”

“It’s going to be a learning experience,” he adds. “Some new builds and self-builds and people who are very clued in will install solar on the roof and use batteries to store the power. But they will soon have a bigger battery outside to power the house during the day and charge up overnight when electricity is cheap. Battery storage is also an enabler of a more dynamic pricing system. The grid is priced half hourly, and this can be passed on to consumers. Smart metering will enable that, so you don’t just have day and night rates.”

This will lead to lots of different tariffs and there could even be times when consumers are paid to take power off the grid. “The real joy of it is that consumers won’t have to make any decisions. The technology will do it all in the background for them,” says Mannion. “We are not quite ready for the electric vehicle revolution yet but we are getting there and it will play a significant role in getting us to a 100 per cent renewables electricity system.”