Solar power is energy from the sun that is converted into thermal or electrical energy. There are several ways to harness solar energy: photovoltaics, solar heating & cooling, concentrating solar power, and passive solar. The first three are active solar systems, which use mechanical or electrical devices that convert the sun’s heat or light to another form of usable energy. Passive solar buildings are designed and oriented to collect, store, and distribute the heat energy from sunlight to maintain the comfort of the occupants without the use of moving parts or electronics.