Photovoltaics (PV) are best known as a method for generating electric power using solar cells to convert energy from the sun into electricity. Solar cells produce direct current (DC) electricity from light, which can be used to power equipment or to recharge a battery. An inverter device is used to convert this DC electricity into AC electricity for the building’s normal electricity supply or to be exported to the grid. There are three basic types of solar cell. Monocrystalline cells, polycrystalline cells and the amorphous or thin-film solar cells. This technology benefits from feed-in tariffs. The European Photovoltaic Technology Platform has produced some useful answers to questions about PV - download the PDF by clicking here.

A solar panel (or solar collector) with a heat transfer fluid flowing through it transports the heat energy collected to somewhere useful, usually a hot water tank or household radiators. The solar panel is located somewhere with good light levels throughout the day, often on the roof of the building. A pump pushes the heat transfer liquid (often just treated water) through the panel. The heat is thus taken from the panel and transferred to a storage cylinder.

Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or, more commonly, a generator can convert this mechanical power into electricity (DC). An inverter device is used to convert this DC electricity into AC electricity for the building’s normal electricity supply or to be exported to the grid. This technology comes with both vertical and horizontal axis turbines and their applicability will vary on surroundings. This technology will soon benefit from feed-in tariffs.

Biomass refers to living and recently dead biological material that can be used as fuel or for industrial production. Most commonly, biomass refers to plant matter grown for use as biofuel, but it also includes plant or animal matter used for production of fibres, chemicals or heat.