Solar electricity: an introduction
Solar panels which generate electricity (known as solar PV) capture the sun's energy using photo voltaic cells. Even on a cloudy day, the cells can still generate electricity which can be used to run household appliances and lighting.
How does solar PV work?
- photovoltaic systems use cells, consisting of one or two layers of semi-conducting material, to convert solar radiation into electricity. The semi-conducting material is generally silicon, which is the second most abundant element on earth after oxygen.
- light shines on the cell creating an electric field across the layers
- this causes electrons to flow creating electricity
- on its own each cell only creates a tiny bit of electricity, but when connected together to form panels, which are linked together to form a system, they create useful amounts
- panels are mounted on the roof or on a frame
- an inverter converts the direct current (DC) to alternating current (AC – or mains equivalent) electricity which is suitable for running appliances
- grid connected systems can export electricity they don’t use to the grid, and import it from the grid when there is not enough sunlight
- off-grid systems store excess electricity in a bank of batteries
- off-grid systems can be used in conjunction with other sources of power such as biomass boilers, wind or hydro turbines.