concentrated solar power: An energy source that employs glass or other material to concentrate light and convert it to electricity. Concentrated solar power, unlike photovoltaics, is usually used in large, centralized power plants.  However, solar water heaters are a decentralized, and cost-efficient, form of solar thermal.

feed-in tariff: Tariffs that require extra payment for renewable energy, usually solar, that goes to the electrical grid. Usually, the money goes to individuals who have installed solar panels. This system incentivizes not only solar installation, but installation of the most efficient solar possible.

gigawatts peak (GWp): A thousand million watts peak (see watts peak).

kilowatt Hour (KwH): A unit of energy equivalent to the work done by one Kilowatt (1 KW) of power expended for one hour. This is more formally expressed in joules: one Kilowatt-hour equals 3,600,000 joules.

megawatt (MW): A unit of energy equal to a million watts. A watt is equal to one joule per second. A Megawatt is not the same as a megawatt-hour, which equals a megawatt expended over an hour.

photovoltaic cells: Cells usually composed of silicon, which acts as a semiconductor to absorb light and transform it to electricity. Photovoltaic cells are most often used as a decentralized energy source located on individual rooftops.

watts peak (Wp): The maximum power output of a 1 square meter solar panel at 25 degrees centigrade. This unit compares the performances of various types solar panels. A 100 Wp panel theoretically produces 100 watts, although in real life it usually produces about 80% of the Wp value. (Definition from