Renewable energy generation

Solar PV Panels

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How do solar panels work?

1.When the sun shines on a solar panel, solar energy is absorbed by individual PV cells. These cells are made from layers of semi-conducting material, most commonly silicon.
2.The PV cells produce an electrical charge as they become energised by the sunlight. The stronger the sunshine, the more electricity generated. But cells don’t need direct sunlight to work and can even work on cloudy days.
3.This electrical charge creates a direct current (DC) of electricity.
4.The direct current passes through a solar inverter to turn it into alternating current (AC) electricity. You need AC electricity to run your household appliances.

How do solar panels work?

1.When the sun shines on a solar panel, solar energy is absorbed by individual PV cells. These cells are made from layers of semi-conducting material, most commonly silicon.
2.The PV cells produce an electrical charge as they become energised by the sunlight. The stronger the sunshine, the more electricity generated. But cells don’t need direct sunlight to work and can even work on cloudy days.
3.This electrical charge creates a direct current (DC) of electricity.
4.The direct current passes through a solar inverter to turn it into alternating current (AC) electricity. You need AC electricity to run your household appliances.

There are also a few things to consider:

The average solar panel system is around 3.5 kilowatt peak (kWp). The kWp is the maximum amount of power the system can generate in ideal conditions.

A 3.5kWp system typically covers between 10 to 20m2 of roof surface area, using between six and 12 panels. 

An unshaded, south-facing roof is ideal for maximum performance. East or west facing roofs still work, but we don’t recommend installing solar panels on a north facing roof. 

A system facing east or west tends to get around 15-20% less energy than one facing directly south. 

If you’re not limited by space inside your home, it may be worth the extra cost of installing a split system. Your installer should be able to talk you through your options and help you choose the design that works best for you
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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, but sometimes shading is unavoidable. Some solar panel systems can minimise the impact of shading using ‘optimisers’. 

Solar optimisers help improve the overall performance of your solar panel system. So, if one panel is shaded, it doesn’t impact how much electricity the other panels can generate. 

If your roof doesn’t have shading, optimisers won’t help you generate more electricity. But having an optimiser gives you extra opportunities to monitor your system’s performance. 

Solar panels on houses are considered ‘permitted development’ and don’t usually need planning permission. But there are exceptions so it’s best to check with your local planning office for guidance. For example, there may be extra restrictions if you live in a: 

  • listed building 
  • conservation area 
  • national park  

If you’re planning to install a solar panel 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 with the DNO for you. 

In Northern Ireland, your installer will register your system with

Yes, it’s okay to install panels on flat roofs. Panels on flat roofs are normally tilted up to help maximise energy production. 

It’s important that the panels don’t disturb the roof covering to keep it watertight. For this reason, many systems are weighted down rather than fixed through the roof covering. 

If you have a system that’s weighted down, the roof needs to be strong enough to deal with the added weight. If the roof isn’t strong enough, use appropriate fixings to ensure rain can’t cause any damage from leaks. 

Sometimes it might be recommended to renew the roof covering so that your roof remains in good condition while the solar panels are attached to it Even though it may add to the cost, the overall solution will be cheaper in the long run. 

The ideal place to install solar panels is on a sloping roof, as the panels work best when angled towards the sun. But if you can’t do that, there are a few other options available to you: 

Yes, you can install panels in the garden on a suitable frame. Make sure they don’t get shaded by nearby trees and buildings, and they should be as south-facing as possible 

One advantage of mounting panels in the garden is that it’s easy to keep them clean. But you also need to be more careful about rodents and other physical damage. 

Yes, you can install panels on an outbuilding. It’s important to make sure that the building roof is strong enough. 

If the building doesn’t have its own electricity supply already then you should factor this in when looking at the total cost of the system. 

Why would I want an air source heat pump?

Cut your electricity bills

Sunlight is free, so once you’ve paid for the initial installation, your electricity costs will be reduced.

Cut your carbon dioxide emissions

Solar electricity is a clean, renewable energy source. A typical home solar panel system could save around one tonne of carbon per year, depending on where you live in the UK. That’s the equivalent of driving 3,600 miles, or from London to Bristol 30 times.

Sell extra energy to the grid

Export the electricity you can’t use yourself and get paid for it. The Smart Export Guarantee lets you sell extra electricity to the grid. This only applies to England, Scotland and Wales. If you live in Northern Ireland, speak to your energy supplier to see if they offer an export tariff.

Installing a solar diverter

Instead of sending surplus electricity to the grid, a solar 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 solar diverter switch installation could add around £800 to your installation costs. You’ll need to replace your diverter after around 12 years.
If you’re interested in using solar diverter, speak with your installer. They might also suggest increasing the number of solar panels on your roof to provide more electricity for your hot water needs.

How much do solar panels cost to install?

Generally, domestic solar panel systems are around 3.5 kWp and cost around £7,000. The cost depends on:
You can lower the cost of installation costs if you already have scaffolding up for roof repairs or if you’re building a new house.
The cost of ground-mounted solar panel systems is more difficult to predict, as there are more variables such as:

Can I get a solar panel grant?

There aren’t any dedicated solar panel grants from the UK Government. But you may be able to get funding as part of other government schemes. You should also get in touch with your energy supplier to see if they offer any financial support for solar installations.

Can I get a solar panel grant?

Get in touch with your local council or energy supplier to see if they offer funding under the

For Scotland

Read our advice on

For Northern Ireland

Get in touch with to find out what funding options are available for you.

How much will I save with a solar panel system?

Running costs depend on how your heat pump is designed and how it’s operated. Savings on your energy bill also depend on the system you’re replacing.
Heat pump running costs can vary depending on:
Here are some typical savings at five UK locations:

What are the best ways to use solar panels?

Solar panels on their own offer lower electricity bills and clean energy. But they’re at their best when combined with other renewable technologies. 

Instead of exporting surplus electricity, you could store it for later use.   lets you save your solar electricity to use when your panels aren’t generating energy. This reduces the need to import and pay for electricity from the grid during peak times. For every unit of electricity stored in a battery and used at night, it will save you around 14p. 

Battery storage tends to cost around £5,000 to £8,000. 

Electric vehicles (EVs) are essentially electric batteries on wheels. You can charge your electric car or van during the day while the panels are generating electricity, reducing your fuel costs. 

Electric vehicles (EVs) are essentially electric batteries on wheels. You can charge your electric car or van during the day while the panels are generating electricity, reducing your fuel costs. 

Most people aren’t at home in the middle of the day to take advantage of the energy generated by their solar panels. When you don’t use the energy from your panels it’s sent back into the grid. 

If you work from home, you’ll naturally use some of the energy yourself. If you’re away during the day, you’re less likely to use this energy, unless you set timers for your home appliances to run during this time. 

Typically, you ‘ll get around 12p for every unit that you don’t use yourself through the Smart Export Guarantee. But since you’d normally buy electricity for more than twice that amount per unit, it makes more sense to use the energy yourself instead of selling it. 

Time of use tariffs 

Some energy providers also offer time of use tariffs, which encourage you to use electricity outside of peak hours when electricity is cheaper. If you have a battery and a time of use tariff it allows you to: 

  1. Store excess solar electricity in the day that you’d have otherwise lost. 
  2. Use this stored energy to avoid more expensive tariff periods. 
  3. Sell electricity from your battery at peak times, if you’re using one of the more innovative tariffs. 

What are the best ways to use solar panels?

Your solar panels should last 25 years or more. But if you have a solar inverter, you need to replace this after around 12 years. 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 you can often extend by up to 15 years. Speak to your installer about the likely lifespan and benefit of an extended inverter warranty.
You might find that a 15-year warranty costs almost as much as a replacement inverter, so consider it carefully.

How do I maintain a solar panel system?

You don’t need to do much to keep your solar panel system running well. The main thing is to keep nearby trees well-trimmed to minimise shading where possible.
In the UK, rain will clean your panels if they’re tilted at 15 degrees or more. 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.
Your solar panel installer should leave written details of any maintenance checks that you should make to ensure everything is working properly. This should include details of the main inverter fault signals and key troubleshooting guidance.
Ideally, your installer should show this to you after installing the system. Speak to your installer for how much maintenance the panels need before you commit to installing anything.

How do I get solar panels?

  1.  Use our  to get an idea of what size system is right for you.
2. Get quotes from at least three installers. Make sure the installers you look at are  which ensures they adhere to a strict code of conduct. It’s also worth getting quotes for a solar battery.
3. Agree a quote with an installer and book an installation date.
4. The installer will install scaffolding before adding the mounts, panels and battery.
5. The inverter is connected to your home so you can start using the electricity generated.
6The installer should test the system and t alk you through how it all works.  
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