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Everything you need to know about Solar Photovoltaic Panels

Wondering if solar panels could work for your home?

Generating your own electricity at home can make a big difference to your bills and help reduce your carbon footprint, we answer some common questions about solar photovoltaic (PV) panels.

Solar Panels illustration

What are solar panels for?

Solar panels are black sheets made of silicon and glass that convert the energy of sunlight into electricity. They can be placed on the top of roofs or in large open areas known as solar farms. Electricity generated by domestic solar panels can be used to power the house they are installed on, whilst solar farms sell their electricity back to the national grid.

Can my appliances run off solar electricity?

 Yes, any appliance that runs on electricity can be powered using solar electricity. 

Are PV systems certified?

Trusted installers are typically registered with the Microgeneration Certification Scheme (MCS). An MCS certificate is a requirement to guarantee access to SEG export tariffs. 

Can solar electricity be stored for later?

There are products known as solar batteries that can be installed in the house, however these are quite expensive and not included with a typical solar PV array. Solar battery technology is advancing and with this the costs are falling. If you have an electric vehicle, this could make the system better value for money. Any electricity that isn’t stored or used is exported back to the grid. 

Does the PV system require ongoing maintenance?

Solar PV systems don’t require much maintenance – you’ll just need to keep the panels relatively clean and make sure trees don’t begin to overshadow them. The inverter might need to be replaced after around 10 years at a cost of between £500 - £1000.

Is my roof suitable for solar PV?

Before investing in a solar PV system, you should check the following: 

1. Is the roof facing south? 

2. Are there any trees or chimneys casting a shadow over the roof? 

3. Can the roof support an additional load? 

4. Are there any roof lights? 

The answers to these questions will determine the effectiveness of any solar array, and might even prevent an array from being installed.

What does kWp and kWh mean?

Kilowatt peak (kWp) tells you the rate a solar PV system can generate electricity when operating at it’s maximum. In ideal conditions, a 1kWp panel will generate 1 kW of power, however in reality this figure will be lower. A standard PV array tends to be between 3 and 4 kWp. Kilowatt hours (kWh) tells you the total amount of energy generated by a solar array, which is affected by the orientation, amount of shading, amount of sunlight, the size of the array and the kWp of the individual panels. A system will typically generate between 700 and 900 kWh per kWp.

How much does a solar PV system cost?

It varies, however a typical system will cost around £1700 per kWp. Therefore, a 3.5kWp array (~25m2) will cost around £6000. The technology is advancing all the time, with the cost coming down a lot in recent years. This trend looks set to continue in the future.

Will I be paid if I generate “too much” electricity to use myself?

Yes, a scheme known as the Smart Export Guarantee (SEG) ensures that small-scale electricity generators get paid by energy companies for the energy they export back to the grid. At the moment, the best tariff is around 15p per kWh

How can I use my array more efficiently?

To make the most of the electricity generated by solar panels, it is advised to run high-usage appliances e.g. washing machines and dishwashers during the day (when the sun is shining). It is also advised to stagger them so they’re not all running at once. Delay-start timers for appliances can help with this

Can solar PV be combined with other renewable technologies?

You can combine solar PV with other renewable technologies such as heat pumps or solar hot water systems.

Do I need planning permission?

You don’t need planning permission to install solar unless you live in a listed building. However, in Conservation Areas or World Heritage sites, the equipment must be installed on the roof, not on a wall that would be visible from a highway.