Plug-in solar is coming. Plug-in batteries should follow.
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Insights<br>Plug-in solar is coming. Plug-in batteries should follow.
Heat & homes
Just transition
Plug-in solar is coming. Plug-in batteries should follow.
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Date<br>May 13, 2026
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WRITTEN By
Lizzy Herratt<br>Graduate energy analyst
Frank Hodgson<br>Demand and flexibility lead
Plug-in batteries could significantly reduce household electricity bills, particularly for renters, flat dwellers and low-income households, who are largely excluded from installing traditional home battery systems today. The government has already announced regulation changes to make plug-in solar panels available as part of its response to the rise in energy costs caused by the US war with Iran. In this blog, Regen argues they should go one step further and make standalone plug-in batteries available too.
The Windfall Battery is a plug-in option designed for flats and renters by London-based start-up Windfall Energy Ltd
Plug-in batteries: putting power in people’s hands<br>Rooftop solar and home battery systems are a well-established pillar of the government’s net zero and energy security strategy. But to date, systems that can be plugged into a regular wall socket have not been legal in Great Britain. This is in stark contrast to mainland Europe, where plug-in systems are commonplace and can be bought off the shelf from Ikea or Lidl.<br>Plug-in solar has been available for almost a decade in Germany, where there are now more than a million systems in place. In March this year, the UK government announced regulation changes to make plug-in solar panels available ‘within months’, as part of its response to the rise in energy costs caused by the US war in Iran. However, the announcement was noticeably quiet on plug-in batteries.<br>In this insight piece, we discuss:<br>What a plug-in battery is and how they work<br>How much households could save<br>Who would benefit (spoiler, it’s those currently cut out from the benefits of home batteries)<br>The wider energy system benefits<br>The next steps for government on safety and regulation.<br>What is a plug-in battery and how does it work?<br>A plug-in battery is a portable energy storage unit that can be plugged into a standard wall socket without any modification to the household wiring. It charges by drawing electricity through the socket – typically during the off-peak period of a time-of-use tariff – and discharges back through the same socket to offset household demand at times when electricity is more expensive.<br>Unlike traditional domestic battery systems, which must be hardwired into the home’s electrical system by a qualified electrician, plug-in batteries can be bought off the shelf and plugged into a wall socket like any other household appliance.
Illustrative schematic of how a plug-in battery can integrate with an existing home circuit and consumer unit to power household appliances.<br>This removes the need for professional installation and significantly reduces the cost compared to a traditional system. Typically around £1,000 to 1,500 of the total cost of a professionally installed home battery is for installation. This cost component doesn’t scale directly with storage capacity, so small systems have a very high cost per kWh. Conversely, unit costs of plug-in systems are very low.
Chart comparing cost per kWh of different scales of battery storage. Regen analysis of UK installation and project costs.<br>How much could households save with a plug-in battery?<br>A battery paired with a time-of-use tariff lets households charge when electricity is cheap and discharge when it is expensive. The household saves money overall when the bill reduction over the battery’s lifetime exceeds its upfront cost.<br>The charts below show Regen’s analysis of cumulative energy spend over 10 years for low-, medium- and high-energy households, comparing two scenarios: a single 3 kWh plug-in battery on the Octopus Go time-of-use tariff against the same household with no battery on a flat-rate tariff. In each case, the battery pays back from around 2.5 years onwards, with 10-year savings reaching up to £2,400 for the high-energy household.
Cumulative energy spends for low-, medium- and high-energy households. A low-energy household may be a flat or one-bedroom house and a high-energy household represents homes with four to five bedrooms and occupants. Typical consumption values from Ofgem were used and it was assumed only one 3 kWh plug-in battery was installed for each case (Ofgem, 2026).<br>Whether a plug-in battery saves money depends on several factors, including the choice of tariff, the battery size and...