New innovations | Technology benchmarks
Voith Hydro has installed the first horizontal, six-nozzle Pelton turbine at Gerlos 1 power plant in Austria
THE TRIAL OPERATION OF the first horizontal, six-nozzle Pelton turbine at the Gerlos 1 pumped storage facility in the Ziller Valley in Tyrol, Austria, has been running successfully for over two months now, and is setting new benchmarks, technology company Voith has announced. In the Pelton turbine, which is especially suited to
Above: Loading the turbine at the Gerlos power plant in Austria. Commissioned in 1949, Gerlos has an annual output of 326 GWh, allowing it to supply renewable energy to more than 70,000 four-person households
plants with high heads, the water is directed by forming free jets at very high velocity from one or several nozzles to the Pelton runner. Until now, Pelton turbines with more than three nozzles have always been designed with a vertical shaft. The main reason for this was that it allowed higher efficiency than a horizontal arrangement. Voith Hydro has now successfully eliminated this drawback, as demonstrated in the Gerlos 1 power plant, where for the first time, an efficiency level comparable to that of the vertical configuration has been achieved. The plant’s existing four vertical Pelton turbines were successfully replaced by one six-nozzle horizontal Pelton wheel.
Applications In addition to this application, the technology is of
particular interest for upgrades of existing hydropower plants where single- or double-nozzle horizontal units are already installed. This is because the turbine can be replaced without major structural works, which significantly reduces civil costs and installation times. At the same time, there is enormous potential for increasing efficiency, said Voith. The associated potential reduction in the number of turbines can likewise lower future maintenance costs. Voith said the new development is also a winning solution for new systems, as it requires less excavation and is more compact with a smaller footprint than conventional solutions. This is also associated with a
Left: Simulation of the horizontal, six-nozzle Pelton turbine
Below: The turbine housing was transported in April 2022
shorter installation time, which substantially reduces the overall investment costs.
Ongoing development work The interaction between the water jet and the buckets
of the Pelton wheel is extremely short, often just a few milliseconds. This is why the flow simulation of Pelton turbines is by far the most complex and difficult of all hydraulic turbomachinery simulations. Voith Hydro has refined the methods in recent years such that the housing flow can now also be analyzed. This important advance also made a significant contribution to the development of the new concept. Since the beginning of the 20th century, Voith
Hydro has supplied thousands of Pelton turbines in a wide range of sizes and outputs all over the world. For many years now, the company in Germany has been conducting intensive research on the concept of multi-nozzle, horizontal Pelton units. The resulting developments of all horizontal Pelton turbines with more than three nozzles are grouped under the designation “HP3+”. Last year, Voith Hydro experts presented the
technology at a leading hydropower conference in Vienna. This world premiere was preceded by extensive tests and pilot programs at the company’s own R&D center in Heidenheim. The first customers, including Austrian utility Verbund, are already using the innovative design.
Impressive transport operation Even before the new unit was commissioned, the
spectacular transport operation for the turbine housing was already causing a stir. At the beginning of April 2022, this 54-ton giant left the grounds of the Voith Hydro plant in St. Poelten, Austria. Apart from its weight, the dimensions of the unit were also impressive: just under nine meters long, more than six meters wide and over four meters high. This logistical masterstroke could only be accomplished by means of a heavy transport operation taking an entire three nights. ●
Below: The turbine underwent extensive tests and pilot programs at Voith’s own R&D center in Heidenheim
26 | February 2023 |
www.waterpowermagazine.com
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