The Vortex Hydropower plant is a type of micro hydropower plant which is capable of producing energy using a low hydraulic head of 0.7–3 metres (2 ft 4 in–9 ft 10 in). The technology is based on a round basin with a central drain. Above the drain the water forms a stableline vortex which drives a water turbine.
It was invented by Austrian engineer Franz Zotlöterer while attempting to find a way to aerate water without an external power source.
The water passes through a straight inlet and then passes tangentially into a round basin. The water forms a big vortex over the center bottom drain of the basin. A turbine is withdrawing rotational energy from the vortex, which is converted into electric energy by a generator.
The turbine’s theoretical energy conversion efficiency is 80%; a test installation reported 73% efficiency, and after a year of use its operation cost was approximately one US dollar per Watt capacity of output.
The inventor refers to the turbine’s aeration of the water, which helps improve water conditions, while the reduced speeds of the turbine and the lack of cavitation ensure that most types of fish can pass through the turbine without danger, something which is much more difficult to achieve at normal hydro plants that require additional structures for the fish migration.