Earthsummit 2002 - A guide to UK Local Agenda 21 renewable energy projects. Earthsummit 2002
Home Page > Solar Power > Photovoltaics (PV).


Photovoltaic cells being made.

Photovoltaic (PV) cells.

A solar photovoltaic (PV) cell is an electronic device that produces electricity when light falls on it. As the light is absorbed by the PV cell it frees up electrons present in the cell, as the electrons move from the cell, they carry with them an electrical charge and are sent to a load such as a calculator or to storage, such as a battery.

A single PV cell can only absorb a small amount of light at a time. So several cells are usually interconnected to form modules to provide larger amounts of electricity. Groups of modules can be mounted together to form a panel. Panels can be interconnected to form a photovoltaic array; these can vary in electrical power depending upon size, from a few watts to thousands. These systems can last a long time; the expected life span is at least 25 years.

PV panels and arrays are becoming increasingly popular and being deployed around the world. Their potential as stand-alone systems is recognised particularly in areas where grid-connected electricity is not available. PV panels are also being integrated into existing buildings by replacing the traditional materials of the roofs and facades. Buildings with PV panels which generating more electricity than they use can sell back the surplus power to the national grid.

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