Plug-in batteries could significantly reduce household electricity bills for renters, flat dwellers, and low-income households excluded from traditional home battery systems. The UK government announced regulation changes to make plug-in solar panels available within months as part of its response to energy costs caused by the US war in Iran, but was quiet on plug-in batteries. A plug-in battery is a portable storage unit that plugs into a standard wall socket, charging during off-peak periods and discharging when electricity is more expensive. Unlike traditional systems requiring professional installation costing around £1,000 to 1,500, plug-in batteries can be bought off the shelf. Regen's analysis shows 10-year savings of up to £2,400 for high-energy households, with payback from around 2.5 years. These batteries could extend benefits to 12 to 14 million households, nearly half of Great Britain, including the 9 million rented and 6 million flat households currently cut out. Under rapid uptake, total discharge capacity could reach almost a gigawatt by 2030.

The Windfall Battery by London-based Windfall Energy Ltd offers a plug-in option designed for flats and renters.