Green Energy

For a long while Savonius wind turbines were popular with the DIY self-sufficiency crowd. Solar panels blew them away in terms of home power generation and lack of maintenance but they were easy to DIY and they work well in the kinds of locations where the big prop windmills don't make sense, like bolted to roofs and to the sides of building.

They do sell premade wind turbines ranging from ones intended for yachts to full size ones but the permies forums have a lot of neat discussions on home small wind and small hydro.