Agua Caliente is one of the largest solar power plants in the world. Located west of Gila Bend, Arizona, the plant already produces more than 250 megawatts, and is expected to produce as much as 397 megawatts when it is complete, sometime in 2014. The plant has 5,200,000 photovoltaic panels, covering around 2,400 acres. Construction began in 2011, and it cost around $1.8 billion. First Solar and NRG Solar are the builders and operators of the plant.