BMW falsehoods

[Murphyv310]

Of course water can be heated by the suns rays by fitting heat exchangers to rooofs. The heated water flows by thermo syphon to a storage tank, valves stop the water cooling by back flow to the heat exchanger at night or if it gets cloudy. I've come across this system twice and even up here it can raise the water temperature to 70c in summer and on a bright winters day over 30c. So having the heat exchanger water system, solar panels and even a 1kw wind generator can all add up to near self sufficiency in energy.
I'm considering a small wind generator to add to my home built solar system.