Why not solar power
Solar power relates to a very different technology – one that directly converts solar energy to electricity. The technology is called photovoltaics or sometimes simply PV. When it’s electricity that’ needed, PV power is one of the most environmentally-friendly ways to produce it. However, the efficiency with which a PV collector can transform solar energy into electricity is low – in the order of 20%. That is, only about 20% of the solar radiation that falls onto a PV surface can be converted into electricity.
This compares with a conversion-efficiency in the range of 70% for solar water heating collectors. Put simply, a square metre of solar water heater collector will produce 3.5 times more thermal energy than a PV will produce electrical energy. What’s more, PV collectors cost substantially more per square metre that do solar water heating collectors. So it’s about selecting the appropriate technology for the application – water heating collectors for hot water and solar power collectors for electricity.