Eel bypass system at hydroelectric power plant

Paul Boughton

The advanced capabilities of SIPOS’ electric actuators are supporting an environmental initiative for an eel bypass system at Unkelmühle - a hydroelectric RWE power plant near Bonn.

As part of its energy policy, the German government is supporting measures for the modernisation of hydroelectric power plants. System upgrades are being encouraged with an incentivised feed-in tariff. Environmental conditions have also been considered, this includes a requirement for turbine intake screens to have lower clearances to guarantee that fish pass parallel to the power plant.

SIPOS’ universally applicable actuator concept enables parallel operation (synchronisation) of several SIPOS 5 actuators without the need for a PLC. Over the entire stroke range, the torque and current position of all SIPOS actuators incorporated into a scheme are monitored and coordinated. Via electronic synchronisation, devices that are long distances apart and impossible to link mechanically can be connected and, if necessary, the traditional mechanical shaft connection can be omitted. The parallel running capability also facilitates the smaller dimensioning of subsequent parts, such as threaded weir spindles or penstocks.

An installation at the converted power station Unkelmühle has been adopted as a pilot project for an eel bypass solution. Designed to address the fact that eels rarely use fish ladders for their descent, a flap (bottom gallery) was installed over the entire base span of the inlet. The flap is periodically operated by two synchronised SIPOS 5 part-turn actuators located both sides of the inlet and connected by cables to the flap. The eels now have the opportunity to bypass the inlet area via the cross flow through the flap and a pipe system.

SIPOS reports that another power station (EOn Gerlachshausen/Lower Franconia) has been equipped with its eel bypass solution.

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