The so-called “Stigler survey” released by the University of Graz in autumn 2005 (also read API 1/2006, pages 9 ff) reveals that the EU Water Framework Directive (WFD) to be implemented by 2015 will have serious consequences for hydropower utilisation in Austria.
In a worst-case scenario (to quote W. Stalzer from BMLFUW), the installation of upstream fish passage facilities and reconnection of river side arms and meanders would cost as much as € 90 million in Austria alone! As a result, some Austrian provinces have already established funding schemes to support ecological improvement measures.
The WFD provisions relating to existing diversion-type hydropower plants, unless already implemented, will necessitate an increase in the amount of compensation water released downstream of the weir. This will cause a substantial drop in the energy output, which not only financially burdens plant operators but also decreases the proportion of renewable energies. And this makes it even harder to fulfill the targets set in the Kyoto Protocol.
Turbine specialist Kössler from Lower Austria has developed a new technology that shall help to solve this problem. The so-called ECO FLOW tubine, which also allows to use the downstream compensation water (or residual flow) for power production, can be easily installed directly at the weir. If properly sized, the ECO FLOW turbine can even turn the proportion of stormwater overflow into electricity that normally runs off unused.
The ECO FLOW turbine developed in collaboration with the Graz University of Technology excels through its semi-regulated design, which means that the wicket gate is fixed whereas the blades are adjustable. The turbine is designed as a Z-tube or open flume turbine and divided in three standard groups depending on the blade diameter. The intake range can be individually adapted according to the respective application.
The flow dynamics of the fixed wicket gate ensure that floating particles and debris are directed towards the turbine axis. A self-cleaning unit, mounted on the turbine axis and rotating synchronously with the turbine, rids the wicket gate from dirt and debris. The inclination angle of the blades is adjustable and allows to customise turbine operation to the fluctuating water flow. The blades are equipped with an oil-free adjustment mechanism and are hydraulically or electrially driven. Rapid adjustment of the blades even makes it possible to keep the turbine in operation during self-cleaning!
The hydraulic turbine system, which was specially designed for semi-regulated applications, offers a wide range of adjustment options, so that efficiency can be kept fairly constant throughout the entire range of applications.
(Source: aqua press Int. 2/2007)
KÖSSLER Wasserkraftanlagen GesmbH
Hauptstraße 122-124, A-3151 St. Georgen
Tel.: ++43/2742/88 52 72
GF Erich Kössler, Ing. Werner Panhauser