The collectors of a parabolic trough system consist of mirrors and absorber tubes to be mounted onto steel support structures in a high-precision way. TSK Flagsol designs and supplies these parabolic trough collectors. The metal frame structure is anchored in the ground with the help of concrete-type pylons. Hydraulic drives assure that the chains of collectors follow the east-west track of the sun along a single axis with a precision of a tenth of a millimetre. The collectors of the plant are controlled with the help of computers installed in a control room.
In a parabolic trough system, the direct normal radiation of the sun is directed onto an absorber tube located in the focus of the collectors by means of parabolically-shaped mirrors. This way, the heat transfer fluid inside the tubes is heated and fed into a heat exchanger where it generates steam for the power plant block. The steam drives a turbine to generate electricity the same way conventional power plants do. Solar-thermal power plants are suitable for industrial power generation with capacities between 50 and 250 megawatt.
Parabolic Trough plants have been in commercial operation for more than twenty years in Kramer Junction in the Mojave Desert of California (USA). Newer plants have recently been built in southern Spain and haven been supplying electricity to the Spanish grid since 2008.
Parabolic trough power plants with and without thermal storages are particularly suitable to be operated in sunny countries with high peak loads, i.e. an extremely high demand at noon and in the afternoon.