Solar PV explained
Solar PV (photovoltaic) technology converts sunlight directly into electricity through the photovoltaic effect. When photons from sunlight strike a semiconductor material (usually silicon), they knock electrons loose and generate an electric current. This is the technology in the solar panels fitted to most homes.
The photovoltaic effect was discovered by Edmond Becquerel in 1839, and the first practical silicon solar cell was developed by Bell Labs in 1954. Over the past 20 years, the cost of solar PV has fallen by more than 90%, making it one of the cheapest sources of electricity ever produced.
Types of solar PV for homes:
- Rooftop PV systems: the standard installation — panels mounted on existing roof structure
- Building-integrated PV (BIPV): solar roof tiles (e.g. Tesla Solar Roof, GB-Sol), solar glass, and facade systems
- Ground-mounted systems: for properties with suitable land, often lower cost per kW
Solar PV is fundamentally different from solar thermal, which uses the sun's heat to warm water rather than generating electricity. Most modern UK homes benefit more from solar PV, which can serve all electrical needs, than from solar thermal, which only heats water.
A typical UK residential solar PV system (3–4 kW) reduces household carbon emissions by 1–1.5 tonnes of CO₂ per year.