The solution to rising electricity bills might soon be found middle aisle of Lidl, with news that high street supermarkets are to start selling cheap, plug-in solar panels . Thanks to a regulatory shake-up by the UK government, smaller plug-in solar panels will soon be appearing on UK shelves. Retail giants including Lidl and Amazon, alongside dedicated power brands like EcoFlow, are preparing to stock these DIY mini power plants for around £400. Portable solar panels offer free, renewable energy that bypasses the need for expensive scaffolding, an electrician’s sign-off or a second mortgage to install. But before you chuck a solar array into your trolley alongside the weekly shop, here’s exactly how this plug-and-play tech actually works, and whether it will genuinely save you any cash in the long run. Get free solar panel quotes Read more: Check out our review of the best portable solar chargers What is a plug-in solar panel? Plug-in solar panels are about as basic as the tech gets.…