Solar PV
Generate electricity from the sun with solar PV panels
Natural light from the sun provides a free and abundant source of energy. A solar photovoltaic (PV) panel is able to convert sunlight into electricity which can be used in the property or exported to the national grid. The panel contains thin layers of semi-conducting material, usually silicon, which is encased between a sheet of glass and a polymer resin. When exposed to daylight, electrons in the semi-conductor material become energised and able to flow through the material, generating a direct current (DC). Cabling is is used to carry the DC electricity from the solar panels to an inverter which converts the electricity to 240V alternating current (AC). This is then connected to the main electricity supply of the property. A generation meter records the amount of electricity generated by the solar PV system.
A solar PV system consists of a series of panels, each with dimensions of about 1.5m x 1m. A suitable array of panels can be designed to fit the size and shape of most roofs. For a solar PV system to achieve optimum performance, the roof should face south and be pitched at between 30 and 40°. Installations with the roof facing anywhere to the south of due east and due west are feasible, although the output will be reduced. It is not recommended that systems are installed on a roof facing north or using horizontal panels. An angle of tilt less than 10° allows dirt to accumulate on the panel.
Another factor which affects the performance of systems is the level of shading which occurs on the roof. Shadows cast by nearby trees, other buildings or chimneys will reduce the electricity generated by the solar PV array.
Solar panels do not require direct sunlight to operate and will still generate electricity on cloudy days. You will generate about one third of the energy on a cloudy day compared to a sunny one at the same time of year. The amount of electricity generated by a system also depends on the location in the UK. Higher levels of sunlight occur during the year in the south west and south of the UK and so the annual electricity generated from a solar PV system in these areas will be somewhat higher. The graph below shows the variation of the electricity generated with month for a typical 3kW solar PV system.
Most solar electricity installations do not require planning permission. Exceptions can apply for flat roofs, listed buildings and those National Parks and other conservation areas or designated landscapes. We would be happy to advise you on the suitability of your property for solar PV and do a free survey.