Eco-premier: Spiral Transports Fish through the Power Plant

15.01.2015Retznei, Sulm

Rotating fish bypass at the VERBUND power plant in Retznei weighs 17 tons.

Ecological Premiere: Screw transports Fish through Power Plant

For the first time, a completely new kind of fish ladder is going into operation at VERBUND’s Styrian power plant of Retznei on River Sulm. The electricity generating hydrodynamic screw has been developed and patented by Lower Austrian company Hydroconnect. The safe transportation of fish takes place via interlocking screws, which are even able to carry a pike, measuring just under one meter in size, both upwards and downwards.

VERBUND, Austria’s largest electricity producer, operates more than one hundred hydropower plants and has selected the Styrian Sulm power plant of Retznei at the mouth of the Mur as the site for an ecological innovation: As a replacement for the conventional fish ladder, the "Albrecht Fish Lift", from Lower Austrian company Hydroconnect, has been installed at the power plant. At the heart of this Austrian invention is a 16-meter-long twin hydrodynamic screw. Manufactured from steel, the rotating screw enables the upstream and downstream migration of fish and microorganisms, whilst simultaneously producing electricity via a generator.

The transportation of fish takes place via two interlocking screws, which convey fish both upwards and downwards by means of the counter-rotating winding mechanism. The "Albrecht Fish Lift" guarantees the safe passage of fish and aquatic organisms whilst simultaneously generating electricity, whereas the required water volume remains energetically unexploited in conventional fish ladders. The fish screw weighs 17 tonnes and was lifted onto the site of the old, conventional fish ladder by means of a crane on the left bank beside the power plant.

The University for Natural Resources and Life Sciences is examining just how well the power plant passage is being accepted by fish

VERBUND is now beginning a trial operation in which 350 litres of water per second are being permanently directed from the Sulm through the fish screw. By means of this volume of water, it is intended that pike, the pilot fish measuring up to 90 centimetres in size, is also enabled an unproblematic ascent from the Mur into the Sulm.

With the commissioning of the fish screw at Retznei power plant, VERBUND is making it possible for fish and other aquatic organisms to pass from the Mur into the Sulm. Just how well the innovative fish ladder is accepted is being examined by means of scientific monitoring. Together with VERBUND, the University for Natural Resources and Life Sciences (BOKU) in Vienna is documenting on a daily basis the species, number and size of the fish using the new passage from the Mur into the Sulm, or vice versa.