Parabolic trough collectors are lightweight structures made of steel and glass. They are the main component of a solar thermal trough power plant for electricity generation. The long, narrow, parabolic-shaped trough collectors consist of precisely curved mirror segments mounted on a torsion-resistant steel structure. To ensure optimal concentration of the sun’s rays, these parabolic troughs are mounted on swivel bearings so that they can track the sun along a single axis. The sun’s rays reflected by the mirrors are concentrated onto a glass-encased absorber tube located on the focal line. A heat transfer fluid flows through this tube, heating it to 400 degrees Celsius. The heated fluid is then fed via central collection pipes to a conventional power plant unit. There, steam is generated in heat exchangers, which is used to drive turbines and, ultimately, generators.

In 1999, a European consortium began developing the EuroTrough parabolic trough collector, with funding from the European Commission’s Seventh Framework Program. Since then, this type of collector—a steel truss structure—has been used in a number of large power plant projects—and, to the surprise of some involved, it remains highly successful to this day, 25 years later. This was followed by further collector developments. First came the HelioTrough, a variant developed specifically for the U.S. market with its high labor costs—particularly on the construction site: Instead of the material-saving torsion box typically used, a standard steel pipe was chosen here as the central load-bearing element, which is transported directly to the construction site, whereas the torsion box must be labor-intensively assembled on site—but uses the material more efficiently. Another advancement is the UltimateTrough, a significantly enlarged version of the EuroTrough designed to reduce costs. It is also ideally suited for systems that use molten salt as a heat transfer fluid.