Photovoltaic Solar Cells

Solar PV cells installed on a roof. Image coutesy of the Energy Savings Trust

Photovoltaic (PV) cells produce electricity from sunlight. A PV cell consists of two or more thin layers of semi-conducting material, most commonly silicon.
When the silicon is exposed to light, electrical charges are generated and this can be conducted away by metal contacts as direct current (DC). An ‘inverter’ is used to convert this DC current into usable AC electricity, which can then be used to power appliances.

The electrical output from a single cell is small, so multiple cells are connected together and encapsulated (usually behind glass) to form a module (sometimes referred to as a "panel"). The PV module is the principal building block of a PV system and any number of modules can be connected together to give the desired scale of electrical output.

PV equipment has no moving parts and as a result requires minimal maintenance. They generates electricity without producing emissions of greenhouse or any other gases, and its operation is virtually silent. Summary Photovoltaics (PV) require only daylight – not direct sunlight – to convert solar radiation into electricity. These systems are neat, unobtrusive and can be fitted on flat or sloping roofs or even mounted on the ground.

Further Information

• NFUS Fact Sheet on Solar PV
• Energy Savings Trust fact sheet on solar PV