Four technologies aim to use heat from the sun to make electricity. But which one has the edge?
Nearly a century ago, American engineer Frank Shuman erected five immense, trough-shaped mirrors in Meadi, Egypt. The parabolic reflectors directed sunlight onto a tube suspended above their 200-foot lengths. Water inside the tubes boiled and created steam. The steam powered a 65-horsepower engine, which pumped 6,000 gallons of water per minute from the Nile River to nearby cotton fields. It was the world’s first concentrated solar power (CSP) plant.