The mercury hit 38.5°C in Cambridge last July, and the UK’s energy grid nearly buckled. At 5pm, when air conditioners roared and fridges strained, solar generation had already slumped by 70% from its midday peak. The gap was filled by gas plants, at a cost of £450 per megawatt-hour, four times the typical winter rate. That spike will appear on every household’s standing charge within months.
This is the context for Ofgem’s decision, as reported by energynews.pro, to back 16 long-duration energy storage projects. The regulator approved a new regulatory framework that will allow developers to build systems capable of storing electricity for eight hours or more, enough to cover the evening peak when solar fades and demand surges.
Who qualifies, and who doesn’t
The 16 projects range from pumped hydro in Scottish valleys to liquid-air batteries in disused salt caverns. They will compete in a ‘cap-and-floor’ mechanism similar to the one that already supports interconnectors: developers get a minimum revenue guarantee, but must repay Ofgem if profits exceed a ceiling. The total capacity, if all are built, is around 4.5 gigawatts, roughly the output of four nuclear reactors.
Households on standard variable tariffs will not see direct grants. But the benefit flows through the wholesale market. When gas plants set the price at peak times, long-duration storage undercuts them. The Energy Systems Catapult estimates that 8 GW of such storage could cut wholesale electricity costs by £2.50 per megawatt-hour, about £22 a year on a typical 3-bed semi’s bill. Not transformative, but a start.
What it costs a typical 3-bed semi
For homeowners, the more immediate question is whether to pair solar panels with a home battery now, or wait for these grid-scale projects to lower time-of-use tariffs. The answer depends on your EPC rating and heating system. A 3-bed semi with gas heating and EPC band D uses about 12,000 kWh of electricity per year, including the heat pump if you’ve switched. A 4 kW solar array plus a 5 kWh battery costs roughly £7,000 installed, and saves around £500 annually on bills under current tariffs.
But the ‘but’ is this: time-of-use tariffs like Octopus Flux or Intelligent Octopus already reward households that charge their batteries from cheap overnight wind and discharge during the evening peak. These tariffs currently offer rates of 5p/kWh for charging and 35p/kWh for export. As long-duration storage comes online, those peak rates may narrow, reducing the incentive for home batteries. Yet the payback period for solar-plus-battery still sits at 10–12 years, well within the 20-year lifespan of the panels.
Surface disagreement: the storage gap
Ofgem’s announcement has drawn criticism from some analysts who point out that 4.5 GW is a fraction of the 30 GW the National Grid ESO says the UK needs by 2035 to meet net-zero targets. The BBC reported last week that existing pumped hydro at Dinorwig and Cruachan provides just 2.9 GW, and new projects take 7–10 years to build. The catch is that the cap-and-floor mechanism guarantees returns, but only for projects that can clear planning and grid connection queues, which currently stretch to 2032 in some regions.
For homeowners, the practical takeaway is this: long-duration storage makes solar more valuable, but the real savings come from pairing it with a smart tariff and a heat pump. Heat pumps shift demand to off-peak hours, and a battery stores cheap electricity for the evening. That combination can cut a typical bill from £1,800 to £1,200, and boost an EPC from D to C or B.
What to do and by when
If you are considering solar panels, book a survey now. The Smart Export Guarantee pays 5–15p/kWh for exported electricity, but rates are falling as more households generate. Install before March 2026 to lock in the current 0% VAT rate on energy-saving materials. For batteries, wait for the October 2024 price review from Octopus and EDF, new time-of-use tariffs are expected that will reward longer-duration storage at home. Ofgem’s grid-scale projects won’t deliver savings until 2028 at the earliest, so home batteries remain the fastest route to lower bills this decade.
Frequently Asked Questions
Not directly, but it will lower wholesale electricity prices during peak hours, which feeds through to your standing charge and unit rate. The Energy Systems Catapult estimates a reduction of roughly £22 per year for a typical household once the projects are operational.
Install now if you have solar panels, a 5 kWh battery can save £200–£300 annually on time-of-use tariffs like Octopus Flux. Waiting for grid-scale storage may narrow peak price differences, but the payback period for a battery is already 6–8 years, and the 0% VAT rate expires in March 2026.
