Concentrating solar power plant. View of 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.