Photovoltaic or solar electric panels generate electricity when exposed to light. The daylight needed to generate the electricity is free, however, the equipment can be expensive.
Suitability for your home
The economics of using photovoltaic (PV) panels for a specific application should be carefully investigated before installation. Different green energy technologies are more suited to some types of homes than others. Contact NI Energy Advice to find out if solar power is right for you - or if you should consider another technology, like wind power or micro combined heat and power.
How PV panels work
PV systems use energy from the sun to create electricity. The panels require only daylight, rather than direct sunlight, to generate electricity. When light shines on a panel, it creates an electric field across layers of silicon in the cell, causing electricity to flow. The greater the intensity of the light, the greater the flow of electricity is. Power can be used straight away or linked back into the power grid.
Installing PV panels
You can use PV systems for a building with a roof or wall that faces within 90 degrees of south, as long as no other buildings or large trees overshadow it. If the roof surface is in shadow for parts of the day, less electricity will be produced.
PV panels are not light and the roof must be strong enough to take their weight, especially if the panels are placed on top of existing tiles.
PV panels come in a variety of shapes and colours, including:
- grey 'solar tiles' that look like roof tiles
- transparent panels that you can use on conservatories or glass to provide shading as well as generate electricity
Most domestic systems are between 1.5 and 3 kilowatts (kW) and can produce around half a domestic property’s electricity requirements.
Solar tiles cost more than conventional panels,and panels that are integrated into a roof are more expensive than those that sit on top. If you plan to have major roof repairs carried out, it may be worth considering PV tiles, as they can offset the cost of roof tiles.
You may have to get planning permission to fit a PV system, especially in conservation areas or on listed buildings. Always check with your divisional planning office about planning issues before you have a system installed. Obtaining planning permission after the system is in place can be difficult and expensive.
Systems that connect to the grid need little maintenance. You just need to make sure that the panels are kept clean and that shade from trees isn't a problem. The wiring and components of the system should be checked regularly by a qualified technician. Stand-alone systems (not connected to the grid) need maintenance on other parts of the system, like batteries.
Remember to insulate first
You should make sure that your property is properly insulated before installing renewable technologies.