I've had an idea to use a gas fired generator running on mains gas to top up a large off grid battery bank when solar power is insufficient. Can anybody tell me if this is legal in the UK? Mains gas is much cheaper than electricity per kwh and the fact I've never heard of anybody doing the same raises concerns as to its viability. Any advice on potential future legislation effecting this kind of setup would also be gratefully recieved. Any work needed would be carried out by an accredited engineer if its legally doable.