Concentrating solar power plant. View of the solar receiver at the Sierra SunTower concentrating solar power plant in Lancaster, California, USA. Concentrating solar power plants use arrays of heliostats (mirrors with sun-tracking motion) to reflect sunlight and concentrate it onto a receiver at the top of a central tower (seen here). The concentrated solar energy is then used to produce electrical power by boiling water to produce steam, which is piped to a steam turbine electricity generator.