First experiences with a 420 kW TUM Hydroshaft plant in the Bavarian Alps

Intro: The TUM hydroshaft powerplant (TUM-HSPP) is an innovative new hydropower concept, which has several advantages with respect to ecology. It differs from conventional hydropower designs as both, the intake and trash rack plain are bottom near and tangential to the riverbed. It is the advantage of this design that in general fish experience low flow velocities at the trash rack and especially low velocity components perpendicular to the bars. Therefore, the chance for fish of being sucked into the intake and into the turbine is very small. Also at the downstream end of the trash rack fish will find a bypass opening in order to migrate from the upstream into the downstream. Altogether there are seven patent families which have been approved or are in the process of being approved in Germany, Europe and the American continents. Two lines of design families can be distinguished: Namely the simple hydroshaft powerplant and the so called TUM multi-hydroshaft power plant concept (TUM-MHSPP), which consists of several shafts arranged laterally of an eco-migration corridor in the river axis and two smaller migration corridors at the river banks (see figure 1). There is also a third variant of the hydroshaft concept under development. A micro-hydropower plant for decentralized energy production in developing countries, where a conventional ship container is used to transport turbine, trash rack and suction pipe. The transport container will then later be used as the intake shaft. Figure 1: Simple, single shaft powerplant (left) and multi-shaft power plant with eco-migration corridor (right). (Th. Kaufmann/TUM) Currently two small pilot plants exist, each about 35kW. One being in Obernach in the Hydraulic Lab of Technical University of Munich (TUM) where design optimizations and tests with living fish had been conducted. Another HSPP was built by a turbine manufacturer as a demonstrator in Heidenheim, Germany. A first and larger powerplant (420kW), situated in a Natura 2000 area near Grossweil at the Loisach River in the Bavarian Alps, will be operational in autumn 2019. The license at this place was challenged in court by NGO’s arguing that two populations of red list fish species, the Danube Salmon (hucho hucho) and the bullhead (cottus gobio) could be endangered by hydropower. Thanks to the extensive tests in the Lab of TUM with living fish, this argument did not count in court. The process ended with a settlement that will not be restricting to the operator. The prognosis is that damage to fish will be in the order of 2,5% for fish migrating either through the turbine or the bypass system into the downstream. Not to say that all fish larger than 200mm would be mechanically protected by the 20mm trash rack.     «

Intro: The TUM hydroshaft powerplant (TUM-HSPP) is an innovative new hydropower concept, which has several advantages with respect to ecology. It differs from conventional hydropower designs as both, the intake and trash rack plain are bottom near and tangential to the riverbed. It is the advantage of this design that in general fish experience low flow velocities at the trash rack and especially low velocity components perpendicular to the bars. Therefore, the chance for fish of being sucked...     »