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.

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.

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.