Other Solar Thermal Technologies
There are two other systems for generating electricity from solar energy. The solar chimney uses a large circular greenhouse to contain air that is heated by the Sun. At its center is a tall tower. Hot air funneled from the greenhouse into the chimney creates a massive updraft that can be used to drive steam turbines to generate electricity. The solar pond is a much more low-technology approach consisting of a large pond filled with brine and exposed to the Sun. When the brine is heated, a hot layer is created at the bottom of the pond and the temperature difference between the bottom and the top of the pond is used to drive a small heat engine. Neither has yet been developed commercially.