Benefits
- Cut your electricity bills
- Reduce your carbon footprint
- Receive payments for extra energy you generate
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.
By installing solar panels, you can generate your own renewable electricity.
How do solar panels work?
A solar PV panel consists of many cells made from layers of semi-conducting material, most commonly silicon. When light shines on this material, a flow of electricity is created.
The cells don’t need direct sunlight to work and can even work on cloudy days. However, the stronger the sunshine, the more electricity generated.
Solar PV systems are made up of several panels, with each panel generating around 355W of energy in strong sunlight. Typical systems contain around 15 panels and generate direct current (DC) electricity. Because the electricity used for household appliances is alternating current (AC), an inverter is installed along with the system to convert DC electricity to AC. This electricity can be used throughout your home, or exported to the grid.
Are solar panels right for me?
Do you have enough space?
Space is a key consideration. The average system size is around 4.2kWp and this will typically take up around 25m2 roof area.
An unshaded, South facing roof is ideal for maximum electrical output. East or West facing roofs could still be considered, but North facing roofs are not recommended. A system facing East or West will yield around 15-20% less energy than one facing directly South.
Shaded roofs
Any nearby buildings, trees or chimneys could shade your roof and have a negative impact on the performance of your system.
Finding an unshaded spot is best, however sometimes shading is unavoidable. Some solar PV systems can minimise the impact of shading using ‘optimisers’. If you don’t have shading, the use of optimisers is not necessary or beneficial, other than the increased monitoring opportunities they offer – they won’t generate more energy.
Do I need permission to install a solar PV system?
Solar PV panels are considered ‘permitted developments’ and often don’t require planning permission. However, exceptions apply and it’s best to check with your local planning office for guidance. If you live in a listed building, conservation area or national park, additional restrictions may apply.
If you’re planning to install a solar PV system in your home, you must register it with your Distribution Network Operator (DNO). The DNO is the company responsible for bringing electricity to your home. Usually, your installer will register the device for you.
The UK Government has advice on how to register your new energy device in England, Scotland and Wales.
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. Find out how much you could save by using the Solar Energy Calculator.
Cut your carbon footprint
Solar electricity is low carbon, renewable energy. A typical home solar PV system could save around one tonne of carbon per year, depending on where you live in the UK.
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 if you’re using more power around your home than your panels are generating, or during the evening when your panels are not generating any electricity, you’ll be supplementing this by importing electricity from the grid.
Reducing your electricity use can help lower your bills and reduce your carbon footprint. If you’re claiming a Smart Export Guarantee tariff, you’ll receive a payment for every unit of electricity you export. Remember to turn devices off and avoid standby.
See our energy saving quick wins for more tips to reduce your energy use.
Use more electricity during the day
As your solar PV system will be working at its peak during daylight hours, it’s a good idea to run your electrical appliances such as your washing machine, dishwasher, and iron during the day. If you’re at home, then this may be easier to do, but if you are away during the day, you could try setting timers for your dishwasher and washing machine.
Combine with other renewable systems
You can combine solar PV with other renewable technologies such as heat pumps or solar hot water systems. These technologies work well with each other, as solar PV could help power a heat pump, for example, or several of these systems could feed into a thermal store.
Install a PV diverter
PV diverters are a low-cost and low maintenance option for increasing your own consumption of solar electricity (ie using the electricity generated by your own solar PV panels).
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 above your demand and exporting that electricity back to the grid.
Instead of sending surplus electricity to the grid, a PV diverter switch can power the immersion heater in your hot water tank, storing hot water for you to use later. On its own, excess solar energy is unlikely to meet all your hot water needs, but it can help reduce your bills.
A PV diverter switch installation could add around £800 to your installation costs.
If you’re interested in using PV diverter, speak with your installer. They might also suggest increasing the number of panels on your roof to provide more electricity for your hot water needs.
You could also export the excess electricity to the grid and consider applying for export payments via a Smart Export Guarantee.
Other options for renewable hot water include solar water heating, or fitting a whole-house heating system such as a heat pump or biomass boiler.
Costs
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 (this closed to new applications at the end of March 2019), 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.
Following the closure of the Feed-in Tariff scheme to new solar PV system applicants in March 2019, the Smart Export Guarantee (SEG) was introduced to provide financial support to small-scale renewable energy generators for the electricity they export to the grid. The savings from solar PV with the SEG are considerably higher than without it.
In Great Britain, the Smart Export Guarantee pays you for the electricity you generate.
In Northern Ireland, you can get paid for any surplus you export – usually estimated based on how much you generate. Several organisations offer this service, so if you’re interested, we recommend researching their offers to find one that works for you.
Costs
The average domestic solar PV system is 4.2kWp and costs around £6,500.
The amount you will pay is influenced by the size of array and will be affected by any difficulty with access to your roof. Some of the installation costs can be shared if you already have scaffolding up for roof repairs or if you are building a new house. Costs are also affected by whether you choose panels or tiles, and whether you opt for building-integrated panels or choose panels that sit on top of your roof. Panels on top of the roof are the cheapest option, while tiles are the most expensive for the equivalent system.
The cost of ground-mounted systems is more difficult to predict, as there are more variables such as the type of mounting frame, and how far away it is from the house.
Costs can vary between installers and products, so we recommend getting quotes from at least three installers.
Maintenance
Solar PV systems need little maintenance. Keep an eye on nearby trees to ensure they don’t begin to overshadow your system.
In the UK, panels that are tilted at 15 degrees or more benefit from being cleaned by rainfall, which helps to ensure optimal performance. Debris is more likely to build up 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 occasionally.
Once fitted, your installer should leave written details of any maintenance checks that you should carry out to ensure everything is working properly. This should include details of the main inverter fault signals and key troubleshooting guidance. Ideally, your installer should demonstrate this to you once the system has been installed.
Keeping a close eye on your system and the amount of electricity it’s generating (alongside the weather conditions) will help you understand 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 around £800 (depending on system size and the manufacturer). Some inverters have online monitoring functions and can warn you by email if the system fails.
Most inverters have warranties of five years as a minimum, which can often be extended up to 15 years. Speak to your installer about the likely lifespan and benefit of an extended warranty. You might find that a 15-year warranty costs almost as much as a replacement inverter, so consider it carefully.
Consult with your installer for exact maintenance requirements before you commit to installing a solar PV system.
