Solar Batteries for Householders

Are solar batteries a viable alternative to exporting to the Grid? Not at the moment, but the technology
landscape is changing fast

By Steven Dale

Sometimes there are straws in the wind which can make you reassess the way the future of a particular technology or trend is likely to shape up. I have come across some of them recently in this corner of the North of Scotland.

Over the course of carrying out energy performance certification in my area, I have noted an increase – small, but significant – in the number of homeowners with solar PV panels who are buying and installing solar batteries rather than exporting their excess electricity production to the National Grid.

Now there are arguments both for and against this kind of considerable investment in the energy future and, at first glance, it just does not seem at the moment that solar batteries are worth the substantial financial outlay that they require.

But as electricity rates remain high – more than double what can be made by supplying to the Grid using the Smart Export Guarantee – does it make sense to store excess energy for later personal consumption? Are battery adopters simply future-proofing their homes?

For now, the numbers are on the side of those solar panel users who export their excess generation for a financial return of around 15p per kWh. More than 1.2 million UK households have panels on their roofs but the number using batteries is only around 10,000.

This is understandable, since the average cost of a battery is prohibitive for many at between £4,000 and £8,000, and most people will have to buy two over the lifespan of their system. In a typical home, it could take more than 20 years to break even.

But what the early adopters are perhaps seeing in advance of everyone else is that the cost of solar batteries is decreasing at the same time as energy prices rise, meaning that, in the foreseeable future, saving the electricity they generate may well become profitable.

A recent study by academics in Finland suggested that battery prices would need to drop to about one-third of their current levels for them to be a viable investment for residential power systems.

Looking to the future, this is perhaps not inconceivable. There is growing optimism not only for the UK battery manufacturing industry, but also for production world-wide.

By 2030, according to the Faraday Institution, around 100 GWh of supply will be needed in the UK to satisfy the demand for batteries for private cars, commercial vehicles, heavy goods vehicles, buses, micro-mobility and grid storage.

This demand is equivalent to five gigafactories, with each plant running at a capacity of 20 GWh per annum. By 2040, demand rises to nearly 200 GWh and the equivalent of ten gigafactories. As production gathers pace, prices will almost certainly fall.

Depending on circumstances, batteries could make sense for homeowners, and certainly in my part of the country increasing numbers of people are betting on them.

But, like all nascent technologies, solar advances are fast-moving and what may seem like the most attractive option now may be less so a few years down the line. Whatever develops, though, it’s pretty certain that green energy will be better than what went before.

Steven Dale is a Surveyor in the Peterhead office of DM Hall Chartered Surveyors.