Concentrating Solar Power (CSP)
Concentrating solar power (CSP) plants are utility-scale generators that produce electricity by using mirrors or lenses to efficiently concentrate the sun's energy. CSP technologies include parabolic trough systems, power towers, compact linear Fresnel and dish systems which concentrate the thermal energy of the sun to drive a conventional steam turbine.
Parabolic trough systems use parabolic curved, trough shaped reflectors to focus the sun's energy onto a receiver pipe running at the focus of the reflector. Because of their parabolic shape, troughs can focus the sun at 30 to 60 times its normal intensity on the receiver pipe. The concentrated energy heats a heat transfer fluid in the pipe which is then used to generate steam to power a turbine which drives an electric generator.
Power tower systems use a field of computer-controlled flat mirrors (called Heliostats) to focus solar heat on a central collector tower. The high energy at this point can then be used to heat water to produce steam (and run a central generator) or it can be transferred to a heat transfer material (typically liquid sodium) which can then store the heat for later use.
The Compact Linear Fresnel Reflectors use flat reflectors moving on a single axis while using a Fresnel lens to concentrate the solar thermal energy into collectors. The flat mirrors used in this system allow for a greater density of reflectors in the array, increasing the efficiency of land use.
Dish systems use a large concave dish to track the sun and focus the energy onto a high-efficiency power conversion unit, which generates electricity directly. Dish systems typically produce upwards of 25KW.
