I'm expecting to have to replace my central heating boiler very soon. It's a big house with 20 odd radiators and UV hot water. There's been a lot of talk recently about smart electricity grid, electric cars and feed-in tariffs etc. I was wondering about a gas-fired micro-CHP unit to generate all my power and heat, and feed any excess electricity to the grid when the heat demand results in an excess. There's lots written about it on line, but has anyone got experience of installing or running such a system and could advise on the real suitability, feasibility and availability at the current state of the technology?