Thermal storage can considerably improve the attractiveness of solar thermal power plants. It allows to extend or to shift the operation of the plant from sunny periods with a high peak demand. Thus, the plant can operate much more flexibly and times of mismatch between energy supply by the sun and energy demand can be reduced. In the present study, the technical and economical feasibility of a two-tank molten salt storage was assessed. No major technical bar-riers were found to realize this concept. The LEC calculation has shown that this concept can improve the economy of parabolic trough plants, provided that the storage is big enough. A storage of 12 h full load capacity reduces the LEC about 10%. Hence, storage systems not onlyimprove the flexibility of solar power plants but also help to reduce the specific electricity cost and thus can support market introduction of the parabolic trough technology.