Engineers are trying to perfect a large-scale solar technology that turns the sun’s energy into electricity—but doesn’t involve expensive semiconductor cells. Solar thermal power systems magnify the sun’s heat and direct it onto fluid-filled pipes, heating the fluid to boiling point. The super-hot liquid is then used to power a turbine generator.
You may be familiar with solar cells, which create electricity when photons from the sun force the transfer of electrons between layers of material. Solar trough plants, on the other hand, involve no chemical reactions. They use an array of mirrors to direct solar heat to a central pipeline filled with water. One such plant in the testing phases in Southern California could help power more than 100,000 homes using a square mile of collectors.