Went to a bracing Science Cafe given by Doug King. His view was that when it comes to environmentally friendly buildings, the 3 most important things are insulation, insulation and insulation. Anything else is mere eco-bling, there for its appearance rather than its utility. In particular it's almost never a good idea to put wind turbines on your house or any other building. They should be situated where it's windy, and where you can build very big ones, and pipe the electricity in.