To store surpluses from fluctuating non-controllable renewable energies, pumped-storage hydropower plant (PSHP) is at the moment the only available bulk energy storage technology. PSHP is a mature technology that can be operated economically with the right framework conditions. But PSHP systems need an adequate geological surrounding. These natural sites are limited in Germany, thus it is important to take artificial structures into consideration as well. The use of the canal system of the federal waterways as a PSHP system is one of these approaches with a high potential of realization.