Generate cheap, green electricity from sunlight
Also in this section
Solar panel electricity systems, also known as photovoltaics (PV), capture the sun's energy using photovoltaic cells. These cells don't need direct sunlight to work – they can still generate some electricity on a cloudy day. The cells convert the sunlight into electricity, which can be used to run household appliances and lighting.
PV cells are made from layers of semi-conducting material, usually silicon. When light shines on the cell it creates an electric field across the layers. The stronger the sunshine, the more electricity is produced. Groups of cells are mounted together in panels or modules that can either be mounted on your roof or on the ground.
The power of a PV cell is measured in kilowatts peak (kWp). That's the rate at which it generates energy at peak performance in full direct sunlight during the summer. PV cells come in a variety of shapes and sizes. Most PV systems are made up of panels that fit on top of an existing roof, but you can also fit solar tiles.
Solar tiles are designed to be used in place of ordinary roof tiles. A system made up of solar tiles will typically cost about twice as much as an equivalent panel system. Solar tile systems are not normally as cost-effective as panel systems, and are usually only considered where panels are not considered appropriate for aesthetic or planning reasons.
A 4kWp system can generate around 3,800 kilowatt hours of electricity a year in the south of England – that's the same amount of electricity as it takes to turn the London Eye 50 times. It will save nearly two tonnes of carbon dioxide every year. A 4kWp system in Scotland can generate about 3,200 kilowatt hours of electricity a year – that’s the same amount of electricity as it takes to turn the Falkirk Wheel 2,100 times. It will save more than a tonne and a half of carbon dioxide every year.
The average domestic solar PV system is 4kWp and costs £5,000 - 8,000 (including VAT at 5 per cent).
|Location||Feed-in Tariff generation and export payments based on a 4kW PV system (£/year)||Electricity bill savings (£/year)||Carbon dioxide (kgCO2/year)|
|System eligible for the tariff between 1st January 2017 and 31st March 2017 (Q1)||System eligible for the tariff between 1st April 2017 and 30th June 2017 (Q2)|
|Cap not reached in previous quarter||Cap reached in previous quarter|
|London, South England||£250||£250||£235||£70||1,900 kg|
|Aberystwyth, Wales||£235||£235||£220||£70||1,770 kg|
|Manchester, North England||£225||£220||£210||£70||1,670 kg|
|Stirling, Scotland||£210||£210||£200||£70||1,580 kg|
Tariffs will also be subject to an adjustment for RPI (Retail Prices Index) so may change from those stated in this table.
For more information about the FITs scheme and recent changes please visit Feed-In Tariffs.
A 4kWp system can generate around 3,400 kilowatt hours of electricity a year – roughly equivalent to a typical household's electricity needs. It will save over a tonnes and a half of carbon dioxide every year.
|System size||NIROCs payment (£/year)||Export tariff payment (£/year)||
Electricity bill savings (£/year)
Carbon dioxide savings (kgCO2/year)
|Belfast, Northern Ireland||4kWp||£270||£70||£80||1,700 kg|
If your system is eligible for the NIROC (Northern Ireland Renewable Obligations Certificates), you could generate savings and receive payments of around £340 a year (based on a 4kWp solar PV system eligible for a generation tariff of 7.94p/kWh, using a ROC rate of 3.97p/kWh). You will get paid for both the electricity you generate and use, and what you don't use and export to the grid if you register before September 2015. When applying for NIROCs you will need to apply through Power NI if your system is below 50kW.
If you know your system size, you can get a tailored estimate of FIT payments for your system using the Solar Energy Calculator.
Costs can vary between installers and products, so we recommend getting quotes from at least three installers.
Solar PV is eligible for Feed-in Tariffs and you will earn a tariff for each kWh of electricity generated by your system. You will also receive another tariff for each kWh of electricity you export.
Solar PV needs little maintenance – you'll just need to keep the panels relatively clean and make sure trees don't begin to overshadow them. In the UK panels that are tilted at 15° or more have the additional benefit of being cleaned by rainfall to ensure optimal performance. Debris is more likely to accumulate if you have ground mounted panels.
Once fitted, your installer should leave written details of any maintenance checks that you should carry out from time to time to ensure everything is working properly. This should include details of the main inverter fault signals and key trouble-shooting guidance. Ideally your installer should demonstrate this to you at the point of handover. Keeping a close eye on your system and the amount of electricity it’s generating (alongside the weather conditions) will familiarise you with what to expect and alert you to when something might be wrong.
The panels should last 25 years or more, but the inverter is likely to need replacing some time during this period, at a current cost of about £800. Consult with your installer for exact maintenance requirements before you commit to installing a solar PV system.