There is one installed on a building near my office. I'll post pics later. The rotor is very simple, like two semi-circular troughs twisted around the central axis. http://www.aerotecture.com/Factsheets.html http://www.aerotecture.com/510VSpec-Sheet2.pdf http://www.aerotecture.com/products.html One needs a strong wind for any appreciable electrical power. One has to so some research on the local wind conditions, probably starting with the local weather station to get an hour-by-hour wind speed curve, and use that to estimate the kWh/yr.