Commercial testing has shown that the 280-megawatt Solana solar power plant situated near Gila Bend in the Arizona desert is capable of generating power even in the absence of sunlight through the use of thermal energy storage.

During the day, the Solana plant makes use of 2,700 parabolic trough mirrors to transfer the sun’s energy onto pipes containing a synthetic oil, which serves as a heat transfer medium. The synthetic oil subsequently flows to boilers where it heats water for conversion into steam, which in turn powers…