Solar PV uses energy from the sun to create electricity to run appliances and lighting. PV requires only daylight - not direct sunlight - to generate electricity.

How it works

Photovoltaic systems use cells to convert solar radiation into electricity. The PV cell consists of one or two layers of a semi conducting material, usually silicon. When light shines on the cell it creates an electric field across the layers, causing electricity to flow. The greater the intensity of the light, the greater the flow of electricity.

PV systems generate no greenhouse gases, saving approximately 325kg of carbon dioxide emissions per year - adding up to about 8 tonnes over a system's lifetime - for each kilowatt peak (kWp - PV cells are referred to in terms of the amount of energy they generate in full sun light).

PV arrays now come in a variety of shapes and colours, ranging from grey 'solar tiles' that look like roof tiles, to panels and transparent cells that you can use on conservatories and glass to provide shading as well as generating electricity. As well as enabling you to generate free electricity they can provide an interesting alternative to conventional roof tiles!

Solar PV and your home

You can use PV systems for a building with a roof or wall that faces within 90 degrees of south, as long as no other buildings or large trees overshadow it. If the roof surface is in shadow for parts of the day, the output of the system decreases.

The roof must be strong enough to take the solar panels weight and the effect of wind upon them.

Solar PV installations should always be carried out by a trained and experienced installer.

Prices for PV systems vary, depending on the size of the system to be installed, type of PV cell used and the nature of the actual building on which the PV is mounted. The size of the system is dictated by the amount of electricity required.

In Scotland, expect a typical yield of roughly 800kWh/kWp/a, although this can be location specific. At 12p/unit, this equates to almost £100 of electricity per annum, although you may not be able to use all of the electricity produced when your production exceeds your consumption. To maximise your gains and thus reduce the payback period, we recommend you switch suppliers to provide you with an export tariff, such as that provided by nPower or Good Energy.

If you intend to have major roof repairs carried out it may be worth exploring PV tiles as they can offset the cost of roof tiles.

Stand-alone systems, i.e. those not connected to the grid, need maintenance on other system components, such as batteries.

Some local authorities require planning permission to allow you to fit a PV system, especially in conservation areas or on listed buildings. Always check with your local authority about planning issues before you have a system installed. Obtaining retrospective planning permission can be difficult and costly.

Are there grants available?

The low carbon buildings programme provides grants towards installing this technology.

For more information call the Energy Agency on 01292-521896 or the EST helpline on 0800 138 8858.

See EST solar PV factsheet.

You may find the EST PV solar guide to generating clean energy informative.

For further information on Low Carbon Buildings Grants see LCBP website. 

Further information can also be found at solar trade association.

Accredited installers and accredited equipment.