Solar PV (photovoltaic) uses the energy from the sun to create electricity to run appliances and lighting. PV requires only daylight – not direct sunlight – to generate electricity, so can still generate some power on a cloudy day. PV systems produce no greenhouse gases.
What are the costs and savings?
You could be saving up to 1.1 tonnes of CO2 a year and £150 – £200 off your electricity bill (assuming the excess electricity is sold to your electricity supplier). The amount of energy each solar PV cell can generate in full sunlight is measured as Kilowatt Peak (kWp). For the average domestic system, costs can be around £5,000- £8,000 per kWp installed, and most domestic systems are between 1.5 and 3 kWp. The Energy Saving Trust gives more details on costs and savings.
Important points
- Any electricity generated that you can’t use may be able to be exported to the grid and sold back to your electricity supplier.
- You need a roof or wall that faces within 90 degrees of south, with no other buildings or large trees overshadowing 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 the roof must be strong enough to take their weight, especially if the panel is placed on top of existing tiles.
- You may require planning permission to fit a PV system, especially in conservation areas or on listed buildings.
- 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.
- PV systems connected to the grid 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. The wiring and components of the system should however be checked regularly by a qualified technician.
