VERBUND's Retznei power plant is a run-of-river plant situated on the river Sulm and in the municipality of Retznei in Styria.
The Retznei run-of-river power plant was built between 1991 and 1992. The power plant generates around 4 GWh of electricity per year and can therefore supply about 850 households in the region with environmentally friendly electricity produced from hydropower.
A fish bypass was already implemented at the Retznei run-of-river power plant during its construction in 1992. A revitalisation took place in 2014/15. A fish screw now carries the fish over the height difference of 5.2 metres from the lower to the upper waters. The fish screw has a total length of 16 metres and runs along the weir wall. The fish are transported by two nested screws which turn in opposite directions to convey fish both upwards and downwards. The “Albrecht fish lift” guarantees safe passage for fish and aquatic lifeforms while also generating electricity; in contrast, the quantity of water needed for conventional fish bypasses remains energetically unused.
Turbines and generators: The double adjustable Kaplan axial turbine with bevel gearbox generates a nominal output of 900 kW. The three-phase synchronous generator has a nominal output of 1,200 kVA, the transformer a nominal output of 1,250 kVA.
Weir system: The weir gate has a “fish belly flap gate” mounted on the reinforced concrete structure which can be raised and lowered by hydraulic drive units.