Domestic solar Panels
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.
The benefits of solar electricity
- Cut your electricity bills. Sunlight is free, so once you've paid for the initial installation, your electricity costs will be reduced.
- Get paid for the electricity you generate. The UK government’s Feed-in Tariff scheme pays you for the electricity you generate, even if you use it.
- Sell electricity back to the grid. You will also receive another payment for the electricity you export through the Feed-in Tariff scheme.
- Cut your carbon footprint. Solar electricity is green renewable energy and doesn't release any harmful carbon dioxide or other pollutants. A typical home solar PV system could save around 1.5 to 2 tonnes of carbon per year.
How do solar panels (PV) cells work?
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 and slates
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.
England, Scotland and Wales
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 around 1.7 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 approximately 1.4 tonnes 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 April 2017 and 30th June 2017 (Q2) |
System eligible for the tariff between 1st July 2017 and 30th September 2017 (Q3) |
||||
Cap not reached in previous quarter |
Cap reached in previous quarter |
||||
| London, South England | £255 | £250 | £235 | £70 | 1, 710 kg |
| Aberystwyth, Wales | £240 | £220 | 1, 590 kg | ||
| Manchester, North England | £225 | £210 | 1, 510 kg | ||
| Stirling, Scotland | £195 | 1, 420 kg | |||
Tariffs will also be subject to an adjustment for RPI (Retail Prices Index) so may change from those stated in this table.
Northern Ireland
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 around a ton and a half of carbon dioxide every year.
System size |
Export tariff payment (£/year) |
Carbon dioxide savings (kgCO2/year) |
||
|---|---|---|---|---|
| Belfast, Northern Ireland | 4kWp | £75 | 1, 530 kg |
Please note, the Northern Ireland Renewables Obligation Certificates (NIROCs) scheme is now closed to all technologies since April 2017 and you can’t receive payments from generation tariffs any more. However, you can still cut your electricity bills by using the free electricity generated by solar PV and receive export payments from the electricity excess that you sell to the grid.
Costs can vary between installers and products, so we recommend getting quotes from at least three installers.
Other factors that affect PV installation costs are:
- The more electricity the system can generate, the more it costs but the more it could save.
- Larger systems are usually more cost-effective than smaller systems (up to 4kWp).
- PV panels are all about the same price per kWp, but PV tiles cost much more than a typical system made up of panels.
- Panels built into a roof are more expensive than those that sit on top.
Solar PV maintenance
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 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 cost of about £800. Consult with your installer for exact maintenance requirements before you commit to installing a solar PV system.
