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Solar panels

Generate cheap, green electricity from sunlight

What are solar panels?

Solar electricity panels, also known as photovoltaics (PV), capture the sun's energy and convert it into electricity that you can use in your home.

Solar PV panels are made from photovoltaic cells, grouped together in modules.

Since solar energy is a renewable resource, by installing solar panels you can generate your own renewable electricity.

solar panels on roof

How do solar panels (PV) cells work?

Solar PV cells are made from layers of semi-conducting material, usually silicon.

When light shines on the material, electrons are knocked loose, creating a flow of electricity. The cells don’t need direct sunlight to work, they can work on a cloudy day. However, the stronger the sunshine, the more electricity generated.

Solar PV cells are grouped into modules, and modules usually grouped into solar arrays – modules and arrays come in a variety of shapes and sizes.

Most PV systems are made up of panels that fit on top of your roof, but you can also install on the ground, or fit solar tiles.

The electricity generated is direct current (DC), whereas the electricity you use for household appliances is alternating current (AC). An inverter is installed along with the system to convert DC electricity to AC.

Are solar panels right for me?

Space is a key consideration. As a general guide, a roof area of 10m2 to 20m2 would be enough to delivery between 20% and 45% of the typical household’s electricity needs.

This roof space will ideally face south, unshaded, and at a pitch angle of about 30 or 40 degrees.

East- or west-facing roofs could still be considered, but north-facing roofs are not recommended.

 Are there any nearby buildings, trees or chimneys that would shade your roof? If so, this will have a negative impact on the performance of your system.

Solar PV installations are classed as permitted developments, but always check with your local authority before installing in case there are any limits or restrictions applicable.

Benefits of solar electricity

 

Getting the most out of your solar PV system

Reduce your electricity use

During daylight hours, you’ll be generating electricity even on cloudy days, but during the evening you’ll be using electricity from the mains. By reducing your electricity use can help lower your bills and reduce your carbon footprint. Remember to turn devices off and avoid standby, and see our Energy saving quick wins for more tips to reduce your energy use.

Use more electricity during the day

As your PV system will be working at its peak during daylight hours, it’s a good idea to think about reorganising domestic activities such as washing, dishwashing and ironing. If you are home most of the day, then this will be easier to do, but if you work during the day then try setting up timers for your dishwasher and washing machine.

Insulate your home

If you have electric heating, programming your timers to come on during daylight hours will help you save money on your electricity bills. To keep that heat in your home for longer, insulate your loft and walls. Draught-proof your doors and windows as well to prevent draughts.

Combine with other renewable systems

You can combine PV with other space-heating renewable technologies such as heat pumps, solar thermal panels and wind turbines. These technologies work well with each other as PV can be set up to help power a heat pump or several of these systems can feed into a thermal store.

PV diverter

Most of the time your solar PV system either:

  • isn’t generating enough energy for your household’s demand, and is supplemented by importing electricity from the grid, or,
  • is generating excess electricity surplus to your demand, and exporting that electricity back to the grid.

If you are getting deemed export payments through the Feed-in Tariff, export payments via Smart Export Guarantee, or if you aren’t getting paid for exports at all, you might be looking for a way to use more of your generated energy within your home.

Instead of sending it to the grid, that surplus electricity could power the immersion heater in your hot water tank, storing hot water for you to use later.

A PV diverter would allow you to do this, provided you have a hot water cylinder. This is typically the lowest upfront cost option for increasing in-home use, particularly if you install at the same time as your panel installation. It is a reliable and low maintenance piece of kit that directs your excess energy to power your immersion heater, instead of exporting to the grid.

On its own, excess solar energy is unlikely to meet all of your hot water needs, but can help reduce your bills.

If you’re interested in using PV diverter, speak with your installer. They might also suggest increasing the amount of panels on your roof to provide more electricity for your hot water needs.

Other options for renewable hot water include solar water heating, or fitting a whole-house heating system such as a heat pump, or wood boiler.

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.

solar slates or tiles on a roof

Export payments

With any domestic PV system there will be times when the electricity you generate is more than you can use or store, so the surplus will be exported to the grid to be used by somebody else. If you want to be paid for exporting, you need to make sure you’re getting an export payment. If you were able to claim the Feed-in Tariff, then you will be getting export payments as part of that. If not, you need to find an energy company that will pay you for this surplus.

In Great Britain, the  Smart Export Guarantee guarantees you payment for the electricity you generate.

In Northern Ireland, you can get paid for any surplus you export – usually estimated on the basis of how much you generate. Contact Action Renewables for more information.
hand putting money into a piggy bank

Costs and savings

 

Following the closure of the Feed-in Tariff scheme to new solar PV system applicants in March 2019, the Smart Export Guarantee (SEG) will be introduced to provide financial support to small-scale renewable energy generators for the electricity they export to the grid. As shown in the tables below, the savings from solar PV with the SEG are considerably higher than without it.

Visit our Smart Export Guarantee and Feed-In Tariffs page for more information about the SEG which applies to solar PV and other renewable energy generators.

London, South East England

Annual Savings

 

Simple Payback

 

Aberystwyth, Wales

Annual Savings

 

Simple Payback

 

Manchester, North England

Annual Savings

 

Simple Payback

 

Stirling, Scotland

Annual Savings

 

Simple Payback

 

Northern Ireland

Solar panels were eligible for Feed-In Tariff payments. The FITs scheme closed to new applications on 31 March 2019. If you have already installed solar PV with a MCS certificate dated on or before 31 March 2019 you may still be able to apply. For more information about the FITs scheme and recent changes please, visit our Feed-In Tariffs  page.

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. 

Annual savings when using the energy you generate

 

Annual income from export payments

 

Other factors that affect PV installation costs are:

  • Typically, 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 about the same price per kWp, but PV tiles cost much more versus the equivalent panel system
  • Panels built into a roof are more expensive than those that sit on top.

Solar PV maintenance

Solar PV needs little maintenance. Keep an eye on nearby trees that they 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, or if you live in an area with more dust in the air. In these cases, you might need to have the panels cleaned.

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 sometime 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.

man installing solar panels on a roof

Helpful resources

More on this…

Solar Energy Calculator

Use the Solar Energy Calculator to gain an idea as to what financial benefits you may see from installing a solar PV system.

Try our tool

Financial support

Find out what support is available for renewable technology specifically in Scotland.

Discover more

Speak with an expert

For independent advice on solar technology, contact your local energy advice centre.

Get in touch