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, even during winter months.
Solar PV systems are made up of several panels, with each panel generating around 400w of energy in strong sunlight. Typical systems contain around 14 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 during daylight hours, stored in batteries that are charges during the day, or exported to the grid for credit on your electricity bills.
Space is a key consideration. The average system size is around 3.5kWp (20m2 or)in urban areas and 5-6KWp (40m2)in rural areas and this will typically take up around 20m2 roof area. Detached homes generally tend to have ample roof space for a larger system.
An unshaded, south facing roof is ideal for maximum electrical output. East or West facing roofs will loose circa 10% percent efficiency but still a good system, by getting more light in the morning and evening. North facing roofs are not recommended.
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.
You can combine solar PV with other renewable technologies such as power diverters or solar hot water systems and EV car chargers. These technologies work well with each other and can be programmed the way you live, diverting power ass you use it on a day-to-day basis.