Sidebar 1: How solar panels work

Thursday, April 2, 2009

The process of converting small particles of light into electricity is called the photovoltaic effect. Photovoltaic (PV) cells convert sunlight directly into electricity. PV cells are usually made of silicon. When sunlight hits the PV cell, the photons "knock" electrons loose from their atoms, creating a current.

Cells have metal contacts on the top and bottom to draw off the current to be used as electricity. Since solar cells are not very efficient, much of the sunlight being either being reflected or absorbed by the cell (like heat). Typically, a cell has an efficiency of about 15 per cent. However, Steven Novack of the Idaho National Laboratories has come up with an inexpensive, foldable solar panel which may turn out to be up to 80 per cent efficient, when and if it comes to market.

The key measures of electricity are:
•     Kilowatt: 1000 watts.
•     Kilowatt hour: A unit of energy equivalent to one kilowatt of  power expended for one hour.
•     Megawatt: one million watts. BF