Solar panels generate electricity from sunlight using photovoltaic (PV) technology. This electricity provides power for the building to which the panel is connected. A well-designed solar PV system can provide up to 50% of the average home’s annual electricity needs.
Electricity from a solar panel system is generated during daylight hours and used as it is made. When the panels aren’t generating enough power for the building, usually at night time and during periods of high demand, the system will automatically draw more electricity from the National Grid.
Solar panels in the UK perform best when facing south, south-west, or south-east, though you can get benefits from systems that face in other directions. Photovoltaic panels can either be fixed to a roof or erected as a free-standing installation.
PV solar cells are made from two layers of semi-conducting material (usually silicon) sandwiched between two electrodes. Groups of cells are mounted together in panels.
When light hits a semi-conductor sandwich, it gives the electrons energy that makes them jump from one layer to the other. This creates a voltage across the solar panel, which then drives current around the external circuit.
PV solar panels generate a direct current (DC). Each system therefore also includes an inverter to convert this into alternating current (AC) suitable for running electrical appliances.
The more light that shines on the panel each year, the more solar electricity it produces. The light doesn’t have to be direct sunlight. Light diffused through clouds also works.
When a PV solar system is connected to the National Grid, any electricity the building can’t use is automatically directed into the Grid. Any electricity the building needs beyond that produced by the solar panels comes from the grid.