RESIDENTIAL batteries for solar power installations are more than just a standard battery, writes Transition Town Wellington.

The new technology in these Battery Energy Storage Systems use their inverter to charge either during low peak electricity times between 2-5am, or from solar or wind power generators, then power the home when needed and/or sell it back to the grid at peak times.

The average residential battery system is around 10kw to cope with the average consumption of 8-10kWh of electricity per household per day.

But could the battery in an electric car be used in the same way?

The answer is yes: the batteries in electric vehicles are much larger, for example the Vauxhall Corsa-e has a 50kWh battery.

New technology called Vehicle to Home can allow you to use an electric car battery to power your home, but only if the vehicle is capable of “bi-directional charging” and you have a compatible smart charger.

There are few electric cars on the market today with bi-directional charging, but hopefully in the future this will come as more standard.

Households and small businesses can now help with peak electricity demand by selling electricity back to the grid, particularly between 4-7pm, which will reduce the need for new power plants or upgrades to the existing grid, which will help reduce the overall cost of electricity for everyone. 

There are many planning applications currently in the UK for huge battery storage plants, which have concerns over both safety from fires near built-up areas, and environmental impact due to the location and size of these plants.

It seems more sense to spread out the storage between existing infrastructure of homes and commercial units which would minimise both of these risks, so people are being encouraged to get a battery with tariffs making it easier to see a return on the investment.

Currently, Octopus energy offer their Flux tarif, which enables households to fill their battery during off peak times (2-5am) for just 17.05p/kWh, much less than the standard daytime charge of 28.42p/kWh. Customers have to on the ball though: if you don’t save enough electric in the battery to cook your dinner, it will cost a whopping 39.79p/kWh to draw power from the grid between 4-7pm! 

It’s not just when importing that the flux tariff can save money.

If you have a battery and solar panels, the export rate during the day is slightly more than the fixed rate (17.42p/kWh rather than the average 15p/kWh most companies offer). If you store up electricity to discharge it at peak hours between 4-7pm, they will pay a great rate of 28.79p/kWh!

With an increase in household solar systems, there is a potential to overload the grid, so they are encouraging people with solar to store excess energy during the sunniest times of day and export it as light fades during peak user times to manage this problem.

So it may be now financially worth investing in a battery, but is it right for environment?

Acquiring the minerals needed for batteries can involve social and human right issues in the places they are mined, and pollution from their processing. These issues could be resolved if consumers put pressure on companies to have more ethical practices.

Recycling is getting better and new types of batteries are being invented too, which is good news. We know we need to switch to renewable energy rather than burn fossil fuels, but their energy production is less consistent.

We need to find innovative ways to balance the grid, while reducing the need for more power stations or huge battery storage plants, and residential installations can be part of the solution