Gars Run-of-River Power Plant

The Gars power plant is a run-of-river power plant on the Inn River in the Upper Bavarian municipality of the same name.

Environmentally friendly

5.170 avoided
tonnes of CO2*

A near-natural fish bypass was put into operation in Gars in 2015. The fish took to the facility straight away, especially the Danube salmon, Austria’s largest domestic fish, which immediately used the fish bypass as spawning ground.

The Gars power plant was expanded in 2013 with the construction of the new Gars power train. Following an investment of around 20 million euros, the power plant now generates an additional 13.5 million kilowatt hours (kWh) from renewable hydropower.

*Source: ENTSO-E Production 2017

Image from the Location

Owner VERBUND Innkraftwerke GmbH
Operator VERBUND Innkraftwerke GmbH
Commissioning 1938
Type Run-of-river power plant
Country Germany
Region Bavaria
Waters Inn
Output 25 MW
Annual output 125,640 MWh
Turbine Kaplan
Connectivity Fish bypass

Each hydropower plant on the Inn comprises:

  • the machinery hall with the turbines,
  • the weir systems for flood release,
  • the dams and dikes for the accompanying flood protection
  • and – if inland drainage has been disrupted by the dams – the pumping stations and ditches, which guarantee agricultural use that existed before construction of the barrage. 

The VERBUND hydropower plants on the Inn are therefore not only plants for generating electricity but also improve flood protection in the region. VERBUND also focuses on improving the ecological conditions at individual sites and on restoring natural river landscapes. We implement a large number of measures in this regard, such as:

  • creating continuity of flow with fish bypasses,
  • giving structure to bodies of water,
  • connecting tributaries. 

In order to guarantee habitats for fish with all their habitat requirements – from spawn to adult specimens – management of the gravel banks is additionally carried out in the near-natural fish bypass or below the weir. Another important component for the long-term conservation of fish fauna is the maintenance of sediment continuity through sediment management, a topic of the EU Water Framework Directive (WFD) for species conservation in man-made rivers.

In 2015, an approx. 680 metre-long near-natural fish bypass was constructed at the Gars power plant. Diverse spawning ground structures in the tributary and artificial bank structures ensure optimal spawning conditions. Sustainable spawning ground management (above all in the area of Gars-Nasenbach) is intended to guarantee accessibility of the spawning grounds, especially during the spawning season. Particular consideration was is given to the requirements of Danube salmon, grayling and common nase. Active habitat management also ensures the proper functioning of the fish bypass. The fish habitats are analysed and potentials for improvement highlighted.
 
Fish populations of the Inn are not long-distance migrants like the salmon and eel, but need the conditions necessary for their survival and breeding during the year over short distances. The accessibility of spawning grounds, habitat for juvenile fish and suitable feeding habitats are just as necessary for this as diverse habitats for floods and winter weather. 

The powerhouse and the weir on the right bank span the Inn, an annex and a switch house are located on the land side and connected to the powerhouse.

Powerhouse: The plant is equipped with five vertical-axis Kaplan turbines. Each turbine has a diameter of 3.9 metres and an output of 4,800 kW. The used head is 7.4 metres. Above the turbines are 50 Hz three-phase synchronous generators with a rated output of 5,000 kVA at a voltage of 6.3 kV.

Weir: In contrast to the powerhouse, which was built as a flat structure, the weir side has five dominant windmill towers with weir bridges, which house the electromechanical chain hoists for the four 17 metre-wide weir fields with double hook gates.

Two 16 MVA power transformers are used to convert the generated energy from 6.3 kV to 110 kV.