I think it was in HK magazine a month or two back that I saw a short article about those two wind turbines. As I recall the article was highly critical of such roof-top power generation and suggested that of the turbines in question one spins but produces very little electricity, while the other is actually hooked-up to an electric motor! While HK magazine has never struck me as being a leading scientific or engineering journal, this last comment nevertheless struck me as being particularly dim-witted. Surely EVERY wind turbine is hooked-up to an electric motor? What is a wind turbine if not an electric motor working in reverse? Almost as bad as when I read a comment from a scientist on the BBC website that, at the start of the universe, the speed of light had been "nearly infinite". I tried to image a superscript '7' lying on its side.