Building power for the people
Kühtai 2 is a hydroelectric power plant being built in the Kühtai Valley in Austria. When completed in 2026, it will provide over 200 million kwh of renewable energy per year to the Austrian grid. At the heart of this huge project are the machines of Volvo Construction Equipment (Volvo CE).
Located at an altitude of 2,000 metres above sea level in the municipality of Silz in the Stubai Alps of Tyrol, Austria, Kühtai 2 is a major project of the Austrian utility company Tiroler Wasserkraft (TIWAG) AG, with an estimated investment of €1 billion. This expansion of the existing Sellrain-Silz power plant series includes the addition of a third water storage system and an additional pumped storage power plant. It will generate around 216 million kwh of electricity per year for the people of Austria, boosting the existing production of 531 million kwh and supporting Austria’s path towards energy transition. As TIWAG says, “this is not a project for TIWAG, but a project for everyone”. Construction management company, Swietelsky, is one of three companies working on the project, along with Jäger Bau and Bodner, as part of a construction consortium and is taking on the technical leadership. The project manager, Peter Wetzlinger, 40, is overseeing the EUR 425 million ARGE consortium part of the project.
“A project like this is not something that happens every day and the human factor is also very important to me,” says Peter Wetzlinger. “We build it together with people and at the end of the day it has to serve people for a long time. “I’ve been here for four years now and I’ll stay until the end. And I’m not alone. It takes a lot of people to make the project work. About 620 people from more than 10 countries work here, it’s like a small village with its own canteen. We are all far from home, so the working and social environment is important, and you also have to like it. It’s not just about the money, but also about being part of the team in a project like this.”
Powerful machines for demanding tasks
The site is a hub of activity with around 200 machines in operation, of which more than 60 are Volvo CE. A brand new Volvo EC950F is the flagship of the excavator fleet. Volvo CE’s largest crawler excavator, this 90-ton giant is the first of its kind in Austria, and a second will soon join the project in Kühtai.
“We simulated loading cycles and this resulted in a demand of between 90 and 100 tonnes,” explains Wetzlinger. “The market for this class of machinery is quite large, but for us the choice was limited by who we wanted to work with. We needed partners we could trust. Volvo CE dealer Ascendum is a reliable partner that offers the high quality we expect.” Above ground, , along with the EC950F, a fleet of Volvo machines, including rubber-tired excavators, Volvo EWR150, EW160 and EWR170, as well as crawler excavators EC220, EC250 and EC380 and a range of Volvo rubber-tired loaders, are working tirelessly. These include a special machine based on the Volvo L180, but with special additional equipment from Finnish parts manufacturer ‘Reptail’. “This works like an asphalt roller and levels the road surface on its own,” explains Wetzlinger. 26 Volvo articulated haulers, ranging in size from the A25 to the A60 – the largest articulated hauler on the market – form the real backbone of the site operations. Their robust design makes them ideal for tough conditions and rough terrain. For underground work and blasting only, fourteen A25 and A30 articulated conveyors are used to carry the material away.
“We optimize the cross-sections so that the loading cycles with the Volvo L120, L150 and L180 wheel loader fit the A25 and A30 perfectly,” says Wetzlinger. “These loading cycles have proven themselves in underground work, including many tunnelling jobs in the past. In small tunnels, the A25s are the best machines for reversing up the tunnel and getting everything out with a full load. Although the skill of the drivers here should not be underestimated!”
Larger hauler models, like the Volvo A40 and A60 were selected for the earthworks because they excel in off-road and challenging applications. “We needed articulated haulers because the rigid haulers can’t get everywhere, especially in certain areas of the quarry. And we can’t create highways. We need all terrain and all-wheel drive vehicles. And this is where the A60 is truly unique and where Volvo CE is leading the way.”
Every week, 30-40 articulated haulers transport 25 tons of bentonite each – a swellable clay material – that is mixed with the core material before being delivered around the site. “Due to the one-way operation, the routes are getting longer, so we are changing the machine fleet and getting more A60 haulers and another large EC950F excavator to help ensure we install the material on time.”
A high-altitude mega project
The Kühtai power plant will be built underground in a rocky cavern, designed to operate as a pumped storage power plant and will be powered by two Flensi turbines, which will generate up to 190 MW of electricity. The construction includes various works; underground, this includes the construction of a network of 8 km of access and feeder tunnels, which are blasted and bored, and a 25.5 km bypass tunnel with a diameter of 4.20 m. It is being excavated with an 800-tonne tunnel boring machine. “It is a gravity tunnel in which water enters through six water intakes at a rate of up to 13.5 cubic metres per second,” explains Wetzlinger. The bypass pipeline will open up new catchment areas in the central and eastern Öztal valley and in the back part of the Stubaital valley, channelling water into the new Kühtai reservoir. The reservoir itself will have a storage volume of 31 million cubic metres and will be filled two and a half times a year, mainly in spring and autumn.
“To fill the reservoir, a 7 million cubic metre dam is being built, with a top length of 500 metres and a height of 106 metres. All materials extracted from the underground area are recycled, while loose rock is installed in the dam. In addition, we have to blast 2.2 million cubic metres of rock – that is about 50-60,000 cubic metres per week. We use 50 tonnes of explosives per week and about 16,000 litres of oil per day. Despite the high altitude, the Volvo EC950F excavator exceeds fuel efficiency expectations, consuming 50 to 55 litres of oil per hour in full operation. “At first we didn’t believe it and thought the machine would consume more,” says Wetzlinger. “But Ascendum’s predictions turned out to be correct.”
Top service for a top project
Ascendum is a valuable partner in the project. “It’s not just about price and fuel, but also about the cost of services,” says Wetzlinger. “We need reliability and good value for money. Kühtai uses some special machinery that is not common, so it takes specialists in case something needs to be repaired quickly. With its large, wide network, Ascendum can have the right people and parts on site within a short time.” The development of Kühtai 2 is a monumental effort, harnessing both human ingenuity and the power of machines to provide sustainable energy for Austria’s future. It is also a testament to the importance of strategic partnerships and cutting-edge technology.
Watch our exclusive video and immerse yourself in the incredible story behind Project Kühtai 2
Volvo CE powers the construction of the Kühtai storage plant in Austria!
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