Hydropower plants play a key role in stabilizing renewable electricity supply. However, extreme conditions such as high sediment loads and exceptional head heights place heavy demands on turbine components and water-conveying parts. Kraftwerke Oberhasli AG (KWO), one of the largest hydropower operators in Europe, has relied for decades on the materials and manufacturing expertise of Deloro Wear Solutions.
With its annual production of CO₂-free electricity, KWO ensures a stable energy supply even beyond Switzerland’s borders. Through customized wear-protection solutions, Deloro helps KWO maximize the longevity and efficiency of its facilities—particularly in developing components that must withstand hydro-abrasive wear.
Founded in 1925 and based in Innertkirchen in Switzerland’s Bernese Oberland, KWO independently operates 13 hydropower plants with 28 turbines, producing around 2,200 gigawatt hours of CO₂-free base-load and peak-load electricity annually. Its 280 full-time employees—highly specialized professionals—produce power that supplies the entire European grid and meets consumer demand on call. Thanks to climate-friendly hydropower generation, KWO contributes to a reliable and consistent electricity network both in Switzerland and across Europe. In the hydropower sector, KWO is one of Deloro’s longest-standing customers.
Hydropower: An underestimated asset for the energy transition
As the energy transition advances, hydropower is becoming increasingly important – its potential is far from exhausted. As a reliable source of CO₂-free energy, it plays a vital role in stabilizing the European power grid and balancing fluctuations from other renewables such as wind and solar. In Switzerland alone, hydropower accounts for about 60% of electricity production, making it the most important renewable source.
In collaboration with KWO, Deloro Wear Solutions provides customized solutions for wear-resistant components, helping to ensure the durability and reliability of facilities. “Hydropower remains a dry subject for many, despite its relevance,” says Maximilian Titzschkau, Data Analysis and Hydromechanics expert at KWO. “That’s unfortunate, because it makes a huge contribution to resource conservation and energy supply.” Material shortages present additional hurdles to expanding and modernizing plants. This makes it all the more important to rely on high-quality components that meet specific requirements—an area where Deloro’s wear-protection expertise is particularly impactful.
Solutions for hydropower challenges
In the demanding hydropower environment, the long-standing partnership between KWO and Deloro Wear Solutions GmbH has proven especially valuable. The two companies have been working together for over 30 years, based on traditional project work—whether modernizing existing plants or constructing new ones. “Our long-term collaboration with KWO and our experience in hydropower allow us to deliver solutions that meet specific requirements, even under complex environmental conditions,” explains Frank Flügel, Customer Account Manager at Deloro.
In Pelton-turbine-powered hydropower plants, adjustable nozzle needles—moved by a servo motor—regulate the water flow onto the runner. For a single turbine, each nozzle can pass up to 4,000 liters of water per second at an exit speed of 120 meters per second. At such high speeds, heavy sediment loads or rock particles in the water often cause hydro-abrasive wear on components. To combat these forces, Deloro and KWO rely on robust, high-performance Stellite alloys.
The key to long-lasting components
Deloro uses specially developed materials and manufacturing processes to counter hydro-abrasive wear. In cooperation with KWO, cast components made from Stellite 3 have proven especially effective. This alloy is highly resistant to heat, corrosion, and abrasion. Its high carbon content increases the volume fraction of carbides, boosting resistance to abrasion and solid-particle erosion.
This makes the material an ideal choice for the conditions faced by KWO’s Pelton turbines. Unlike Kaplan or Francis turbines, Pelton turbines are particularly demanding, operating under high net head and sediment load. At Deloro’s Koblenz facility, nozzle needles and rings are made from highly wear-resistant cobalt-chromium (CoCr) alloys—100% “Made in Germany.” The process starts with casting raw parts in a traditional sand-casting process at the in-house foundry. This is followed by mechanical finishing: turning, grinding, polishing, and, if needed, drilling.
An alternative to solid cast components is coated parts. Alongside common high-velocity oxy-fuel (HVOF) spraying with tungsten carbide, Deloro also offers thicker coatings applied via laser cladding with Stellite, providing a decisive advantage in wear resistance and durability.
For KWO, Deloro conducts extensive quality inspections. Surface crack testing checks for the finest cracks in the cast, while ultrasonic testing uses sound waves to detect internal flaws. The result: durable, corrosion-, abrasion-, and heat-resistant components. “Thanks to Deloro’s expertise, we’ve been able to extend the service life of our nozzle needles by three to five times,” says Maximilian Titzschkau. “The economic break-even point is around 20,000 operating hours—anything beyond that is a real gain for us.” Wear-protection solutions tailored to the specific conditions can extend turbine operating life from just a few hundred hours to several thousand.
Three decades of successful collaboration
The ongoing partnership between Kraftwerke Oberhasli and Deloro over three decades shows how important customized solutions are for long-term success in hydropower. “Our long-standing cooperation with KWO is not just a success story, but also proof that our high-quality, reliable solutions have proven themselves in hydropower,” says Volker Streit, Business Development Manager at Deloro. With powerful, high-quality alloys, Deloro not only helps increase operating times but also supports KWO in strengthening its role as a dependable energy provider in the European grid.
