Case study: river turbines provide ecologically acceptable power

These innovative turbines convert the energy of the river water into electric power and feed this into the power supply system. In doing this, there is no need for the water either to be impounded or diverted.

Following the successful operation of the two prototype turbines anchored to the river bed downstream from St. Goar, KSB now intends to prepare the newly developed power generators for commercial use. “We believe in a type of power supply that aims at economic effectiveness, reliability of supply and ecological compatibility all at once,” says Prof. Dr. Dieter-Heinz Hellmann, member of the KSB AG Board of Management. He adds that with the development of the river turbine, KSB is now in a position to offer a new means of generating power within the scope of “small hydropower” that is not only clean but also capable of providing base load.

The design of the river turbines is based on an axial flow propeller pump running in reverse rotation mode and called for extensive and complex tests on models installed in a flow channel in order to determine their ideal exterior shape. To make sure the turbine would be accessible for inspection and maintenance, plus would not get in the way of passing vessels, the unit had to be fixed to the river bed using a specially designed anchoring mechanism. Also the water intake had to be designed in such a way that fish and flotsam are unable able to enter the turbine unit.

The project is being supported by the Ministry of Environment, Forestry and Consumer Protection of the German Federal State of Rhineland-Palatinate. Minister Margit Conrad travelled to Frankenthal specially to attend the recent commissioning ceremony where she was asked to give the starting signal for the feed-in of electricity controlled from the company headquarters. Minister Conrad acknowledged the success of the pilot installation set up for the purpose of testing two river turbines, which have been designed to generate power without affecting climatic conditions or the environment.

The two turbines are the latest of KSB AG’s efforts to supply the market with innovative products”, commented Minister Conrad at the commissioning. “The river turbine installation is a good example of how, through the use of cutting-edge technology, a body of naturally running water can be utilised in a highly efficient manner, yet without harming the fish population or getting in the way of passing vessels.”

In Germany, hydropower is the second most important regenerative energy, only to be surpassed by wind power. KSB believes that the hydropower share offers potential for further growth. In Germany alone, one could potentially generate hydropower in the range of 6.8 TWh per year – without cross-structures, i.e. without major changes to the natural landscape.

The German Federal Government supports these types of power stations which have a total output of less than 500 kW, by paying a feed-in compensation in the amount of 12.67 eurocents per kWh. However, KSB also believes there is a market for “small hydropower” internationally, particularly where the problem of supplying rural areas with electricity calls for creative solutions.