Back in the 1970s, a German utility wanted to build a flexible storage plant<br />that could respond to sudden peaks in electricity demand, since its conventional plants — mainly coal — weren’t designed to dial up or down quickly.<br />It is the world’s first utility-scale concentrating solar power plant that uses extremely hot salt to extend the use of solar energy way past sundown.<br />Today, with the rise of green energy sources like solar<br />and wind, the need for industrial-scale energy storage is becoming ever more vital to make sure there’s power even after the sun sets or the breeze dies down.<br />The salt, which can stay liquid at higher temperatures than some other fluids like water, then flows through a steam-generating system<br />that drives a turbine, producing enough electricity for 75,000 homes for as long as 10 hours past sundown — in essence, allowing the sun to shine at night.<br />The plant, which opened in 1978, uses electricity from the grid, when it’s cheap because demand is low, to compress and store air in the salt caves.<br />A similar plant opened in 1991 in McIntosh, Ala. Several energy companies, mainly in the United States<br />and Europe, are exploring mining their salt deposits for storage as well.
