The UK’s electricity grid will soon have another 125 megawatts of battery storage capacity, after Island Green Power secured consent for a new project. That is enough to power roughly 125,000 homes for an hour during peak demand, or, more practically, to soak up excess solar generation on a sunny afternoon and release it when the evening kettle rush begins.
The project, as reported by Solar Power Portal, is part of a wave of grid-scale battery projects that have surged in planning approvals over the past two years. The UK now has around 4.5GW of operational battery storage, with another 20GW in the pipeline.
Why this matters to your electricity bill
Every time the grid burns gas to meet peak demand, the cost is passed to households through the wholesale energy component of your bill. National Grid ESO estimates that using storage to shift renewable power into peak hours could save the system £200–£300 million a year by 2030, equivalent to roughly £5–£8 off the average household’s annual electricity bill. That figure is modest now, but as more batteries come online, the savings compound.
Ofgem’s latest network charging reforms, due to take effect in 2026, will also reward batteries for locating near demand centres. That means less transmission infrastructure is needed, reducing the ‘green levies’ and network costs that make up about 25% of a typical dual-fuel bill, currently around £340 per year for a 3-bed semi using 2,900 kWh of electricity.
Who qualifies, and who doesn’t
Grid-scale batteries are not a direct consumer product. You cannot buy one for your home and plug it into the street. But if you already have solar panels and a home battery, you are already doing at the household level what Island Green Power is doing at grid scale: storing cheap solar power for evening use.
The Energy Saving Trust says a typical 4kW solar system with a 5kWh battery can cut a household’s grid electricity imports by 30–40%, saving around £200–£400 a year depending on tariff. The new grid-scale battery will not change those numbers directly, but it will make the overall grid cleaner and cheaper to run, and that benefits everyone, whether they have solar panels or not.
What this misses
The catch is that battery storage alone does not solve the UK’s energy affordability crisis. The British electricity market still prices power at the marginal cost of the most expensive generator, often gas. Until that market design changes, the wholesale price savings from batteries will be limited. Ofgem is consulting on ‘locational marginal pricing’, but no decision is expected before 2027.
Nor does this project address the upfront cost of home batteries. A 5kWh battery costs around £2,000–£3,000 installed, and the Smart Export Guarantee pays only about 5–15p per kWh exported. For most households, the payback period is 5–7 years without a heat pump or electric vehicle to increase self-consumption.
What to do and by when
If you are thinking about solar and battery storage, the best time to act is before October 2025, when the VAT on battery-only installations reverts from 0% to 20% unless the government extends the relief. For now, a solar-plus-battery system installed before March 2027 qualifies for 0% VAT under the current rules.
Check your eligibility through the Energy Saving Trust’s online tool or speak to an MCS-certified installer. For those not ready to invest, simply switching to a time-of-use tariff like Octopus Flux or EDF’s GoElectric can reduce your electricity bill by 15–20% if you can shift washing, drying, or EV charging to off-peak hours, typically 11pm–5am.
Frequently Asked Questions
Yes, but the direct impact on your bill will be modest initially. National Grid ESO estimates grid-scale batteries could save the system £200–£300 million a year by 2030, which equates to roughly £5–£8 off the average UK household's annual electricity bill. Savings will grow as more battery capacity comes online and reduces reliance on expensive gas during peak hours.
A typical 5kWh home battery costs between £2,000 and £3,000 installed in the UK. The payback period is usually 5–7 years, but this improves if you have a heat pump or electric vehicle to increase self-consumption of stored solar power. The Smart Export Guarantee pays around 5–15p per kWh exported.
No, grid-scale batteries like the 125MW Island Green Power project are not consumer products you can buy for your home. However, if you have solar panels with a home battery, you are already doing the same thing at household level: storing cheap solar power for evening use. The Energy Saving Trust says a 4kW solar system with a 5kWh battery can cut grid imports by 30–40%, saving £200–£400 a year.
Ofgem's network charging reforms, due in 2026, will reward batteries for locating near demand centres. This reduces the need for new transmission infrastructure, which should lower the 'green levies' and network costs that currently make up about 25% of a typical dual-fuel bill – around £340 per year for a 3-bed semi using 2,900 kWh of electricity.
Not on its own. While batteries help shift renewable power to peak times, the UK electricity market still prices power at the marginal cost of the most expensive generator – often gas. Until market design changes like Ofgem's proposed 'locational marginal pricing' are implemented (no decision expected before 2027), wholesale price savings from batteries will remain limited.
