Solar Power - Solar PV (Photovoltaic)
Having a solar PV system installed on your property can be a great way to reduce the cost you pay for your electricity. As with other solar products, photovoltaic solar systems use daylight energy from the sun to generate the electricity, which runs appliances and lighting in the home; meaning less electricity used from your traditional supply and thus lower energy bills.
The cells used to convert solar radiation into electricity consist 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.
PV systems now also come in a variety of shapes and colours, ranging from grey 'solar tiles' that look like roof tiles, to panels and transparent cells that can be used on conservatories and glass to provide shading as well as generating electricity.
Solar PV and your home
PV systems can be used for a building with a roof or wall that faces within 90 degrees 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.
Solar panels are not light, and so the roof must be strong enough to take their weight, especially if the panel is placed on top of existing tiles.
Solar PV installations should always be carried out by a trained and experienced installer.
Cost and maintenance
Prices for PV systems vary, depending on:
- The size of the system to be installed (dictated by the amount of electricity required),
- The type of PV cell used, and
- The nature of the actual building on which the PV is mounted.
For the average domestic system, costs can be around £4,000- £9,000 per kWp installed, with most domestic systems usually between 1.5 and 2 kWp.
Solar tiles cost more than conventional panels, and panels that are integrated into a roof are more expensive than those which are installed on top.
If you intend to have major roof repairs carried out then it may be worth exploring PV tiles, as they can offset the cost of roof tiles.
Grid connected systems require very little maintenance, generally limited to ensuring that the panels are kept relatively clean and that shade from trees has not become a problem. However, the wiring and components of the system should be checked regularly by a qualified technician.
Standalone systems, i.e. those not connected to the grid, will 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, because obtaining retrospective planning permission can be difficult and costly.
Save even more on your electricity
If you would like to further reduce your electricity bills, you can enter your postcode into the form on the right to find out if you could be on a more competitive energy tariff.
It’s possible that you could be overpaying for the electricity you use simply due to the tariff you’re on or the supplier you’re with, so it is often a good idea to compare quotes for various tariffs and suppliers to potentially find yourself a cheaper overall tariff to switch to.
Source: The Energy Saving Trust January 2007.
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