How do photovoltaic (PV) cells work?

PV cells are panels you can attach to your roof or walls. Each cell is made from layers of semiconducting material, usually silicon. When light shines on the cell it creates an electric field across the layers. The stronger the sunshine, the more electricity is produced.

PV cells come in a variety of shapes and colours, from grey "solar tiles" that look like roof tiles to panels and transparent cells that you can use on conservatories and glass.

The strength of a PV cell is measured in kilowatt peak (kWp) - that's the amount of energy the cell generates in standard test conditions and is not what you can expect to generate. The amount generated is dependant upon location, shate, orientation and most importantly - the weather.