Arizona has just pulled ahead in the race to see which state can produce the cleanest and most efficient green energy with its new solar plant with the ability to generate energy even at night.
Arizona’s new 1.45 billion dollar Solana Generating Station near Gila Bend is the largest capacity solar thermal plant on the face of the Earth.
What is even more remarkable is the ability of the solar plant to keep producing energy at night. Constructed by a Spanish energy giant company, Abengoa Solar, and named “Sunny Spot”, the plant has a total capacity of 280 megawatts, which is enough to power almost 100,000 homes and greatly reduces the carbon dioxide output.
Current conventional solar plant designs use mirror arrays to focus energy to a central point, which is used to boil water to create steam to power a turbine. Up until now these plants were limited by the amount of sunlight they could absorb during the daylight hours, but now with the addition of salt tanks the energy producing systems are looking more efficient. This is the first American plant using this new design.
Twenty-seven hundred mirrors focus the sun’s rays onto a synthetic oil, heating it to 735 °F. This working fluid then flows into steam boilers to heat water and drive a 140 megawatt turbine. But this working fluid isn’t done yet; any residual heat from the fluid is then siphoned off by a set of six tanks holding a combined 125,000 metric tons of salt. These salt tanks remain at roughly 530°F during the day. Impressively, the Solana plant produces power for an additional six hours after the sun has gone down thanks to its huge molten salt thermal storage.