A month after plug-in solar became legal in Great Britain, the shape of the new market is starting to show, from who is selling kits and who is buying them – and where the rules are still catching up.
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Energy supplier Octopus, which was among the first to put plug-in kits on sale, sold its first 500 kits within two weeks of launch and has since sold out a second batch, a pace it says left it “blown away” by demand. The company says thousands of households have tried to buy one, and the interest was there before launch: in a May survey for price comparison site Uswitch, about a quarter of UK households said they were keen on plug-in solar. Among Octopus’s early buyers, nine in ten chose the two-panel bundle at £650 over the single-panel version at £450. This rush coincided with a 4 percent rise in the energy price cap on 1 October, which left many households paying more again for heating and power.
Small print and safety
Not every kit on sale can be legally plugged in. That is decided by a compliance register kept by the Energy Networks Association. A kit only qualifies once the complete product, from panels and inverter to cable and plug, is listed as compliant. Labels do not always make this easy. Some kits are sold as 890 W or even 1,260 W, which is allowed because the rules permit up to 2,000 W of panels as long as no more than 800 W reaches the socket.
Before the rules took effect, the main electrical trade and safety bodies warned against a rushed rollout, with Electrical Safety First pointing to possible interference with residual current devices and to standard plugs never having been designed for generation. The government says independent tests show compliant kits are safe and work with UK wiring, and that its rules are stricter than Germany’s. Consumer group Which? has advised households with older wiring to get their electrics checked first.
Pennies and paperwork
Selling surplus power back to the grid is not yet as straightforward as many consumers would wish. Plug-in systems do not currently meet the certification and metering criteria for the Smart Export Guarantee, so Octopus is offering its own Outgoing tariff and British Gas is working on a similar scheme. Either way, the savings are likely to be modest. The government puts typical savings at £70 to £110 a year and Octopus at up to £150, and experts expect kits to pay for themselves in three to five years. Every owner must also notify their network operator through the UK Plug-in Solar Registration service, so there is some paperwork involved.
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For now, any power produced by the kits must be used or exported straight away. The rules on socket-connected panels exclude plug-in batteries, and the government is expected to consider these separately, possibly next year. In the meantime, Solar Energy UK has asked for a safety study on plug-in batteries along the same lines as the study carried out for panels. In anticipation of a rule change, Octopus is lining up its 2 kWh Nook Cube for launch in the first quarter of 2027 and describes plug-in batteries as the “real game-changer”, one that fits its wider push to get households onto smart tariffs.
For all the early sales, Britain is starting from a low base. Germany, where the format took off under looser rules, added around 500,000 units last year alone, and the UK version comes with a mandatory registration step that most European markets do not require. But the appetite is clearly there, and the gap could narrow quickly once batteries are allowed.
Taking back a little control
After two price shocks in four years, many households want more say over where their power comes from. In the same survey for Uswitch, 40 percent of bill-payers said recent prices had made them more likely to generate their own electricity. Plug-in kits will not make anyone self-sufficient, but they offer renters and flat-dwellers a first step towards producing their own power – something rooftop solar has never been able to give them. (TF)
