Large movable mirrors known as heliostats are arranged in concentric circles at the PS20 solar power plant near Seville, Spain. The facility contains a total of 1,255 heliostats that reflect sunlight up to a receiver on top of a 165 meter (541 feet) high tower. This energy is then used to heat molten salts that circulate from the tower down to a storage tank, where it is used to produce steam and ultimately generates enough electricity to power 180,000 homes.