CHP (Combined Heating & Power)
Micro CHP units are set to replace the conventional domestic central heating units over the next decade. They work in a similar manner to a conventional domestic central heating boiler unit but the waste heat is captured and used to power a (Stirling) hot air engine, this generates mains rated electricity that can be used or exported back onto the grid.
Once these units are mass produced (Pilot schemes are running now Feb 2010) then they will be available second hand. I predict that in the not too distant future off-grid homesteaders will be running these in remote locations on Wood, Waste Veg Oils and other sources of renewable heat sources to produce heat and power.