New hydropower station Kostheim
Before the project began, the dam Kostheim am Main consisted of a 3-section weir system including 2 locks. In 2006, the implementation planning of a hydropower plant was started. The new construction of the hydropower plant is located on the right bank of the existing dam Kostheim/Main. Flooding safety was an essential criterion for its design and construction height as flooding of the Mainau flood plains can occur in extreme flood water levels. Another special feature is the strongly fluctuating water level of the underwater influenced by the Rhine. This led to the necessity of adjusting the turbine speed via a variable-speed gearbox. This in turn allows a better utilization of the water supply, as fall height and flow through speed variability can be better adapted.
19m below the water level of the dammed Main, just 5m away from the shipping lane, the 60m long excavation pit was built. The overcut bored pile walls were made stable by internal stiffening with steel pipes and could be adapted by capsule presses to the respective ambient conditions of ground and air temperature, an economical system was implemented. Inflow and outflow were numerically optimized so as not to lose any drop height due to poor flow conditions.