Eel protection

RWE Power AG operates 44 run-of-river power plants for its fellow subsidiary RWE Innogy. New statutory provisions and findings about nature conservation and water pollution control in part make optimizations necessary, mainly with regard to fish protection. Today the eel stock in Europe is highly endangered due to the fact that the fish are exposed to numerous harmful influences during their complex life cycle. While migrating to their spawning areas, eels occasionally pass the turbines of hydropower plants and due to their length may be injured by the turbine blades.

On the Moselle River in particular, where RWE operates ten run-of-river power plants, we want to contribute to the preservation of a secure eel stock. To this end, we founded a cooperation with the Federal State of Rhineland-Palatinate and professional fishermen in 1995.

Within the scope of the EEL PROTECTION INITIATIVE IN RHINELAND-PALATINATE we are investigating possibilities of minimizing fish injuries caused by hydropower plants and enhancing the eel stock in the Moselle in collaboration with scientific institutions. The central idea behind this effort is to strike a balance between ecological and economic interests in order to ensure climate-friendly electricity generation from hydropower.

We pursue a holistic approach to eel protection. We do this by researching, developing and testing of suitable supporting measures as well as providing immediate aid and conducting basic research.

Since 1997, migrating eels have pinpointedly been caught upstream of the various hydropower plants and carefully relocated as an immediate aid measure. Per year, about 10 – 15,000 Moselle eels can in this way reach the Rhine River unharmed to continue their migration. Several research studies have gained and still are gaining findings about the biology and migratory behaviour of eels. Among other things, the aim is to identify the migration times of eels so as to be able to take suitable supporting measures at those times. In 2011 there will be a study on the development of the eel population in the Moselle. Until now, the eel population can only be guessed. With the help of a dynamic population model the current eel population and for example essential causes of death shall be identified.

One promising measure could be a fish-adapted operating mode where the turbine flow is not predominantly optimized energetically but rather controlled such that maximum space between the turbine blades minimizes the risk of injuries for eels. We have assigned RWTH Aachen University with identifying suitable control variants and analyzing them as to their effectiveness. The success for the eel population of the Moselle is being determined in a comprehensive fish biological study that is conducted in parallel. The vast majority of the eels migrate in certain nights under certain environmental conditions. For this reason, we are reviewing a detection method that will help us to determine these main migration nights. A fish-adapted operating mode could contribute to a mitigation in these periods without substantially affecting the power generation.