Electricity from the sun

Solar photovoltaic
 

 5kW array Swanage

Solar photovoltaic cells produce electricity when sun shines on them. The word photovoltaic comes from photo meaning light and voltaic meaning electricity.  The technology is well established and widely used on watches, calculators, garden lighting, parking meters, "slow down" traffic signals.  If you are local look out for them on the roofs of BP petrol stations and several local schools.

A typical domestic system will cover all of the “sunny” side of your roof and generate around half of your electricity needs. 

Rules of thumb are 10 square meters per kilowatt peak, most domestic systems are around 2kWp - this means that at noon on a sunny day you will generate 2kW - enough to boil a kettle.  Providing you are grid connected you can export to the grid when your system is generating more than it uses, and import when you are using more than you are generating.  If you are not grid connected you can store electricity in a battery system.

The cost of installing solar PV is coming down dramatically. However, there is also an incentive to invest in this technology as the Feed In Tariff provides an index-linked tax-free payment for all the electricity generated, and a payment for the electricity exported to the National Grid, for 25 years. See the Feed In Tariff fact sheet, FIT Facts, for further information.

Solar Photovoltaic factsheet