Alpine wind farm

The challenge

Challenge for people and machines

Road transport from the factory in Germany, load transfer in Mürzzuschlag (Austria), mountain transport and assembly: Prangl put together a total package for the new wind turbines. This naturally included support for advance planning of routes and crane parking areas. Special equipment designed specifically for transporting and lifting wind turbine components was deployed.

Our solution

Special equipment

The road transport was undertaken by various machines, depending on the load: a four-axle tractor unit with a tower adapter for the steel towers, a five-axle tractor unit with a four-axle blade trailer for the rotor blades, a three-axle traction unit with a nine-axle semi-trailer for the nacelles, a three-axle traction unit with a one-axle dolly and a four-axle low-bed semi-trailer for the hubs, and a three-axle traction unit with a two-axle dolly and a four-axle or six-axle low-bed semi-trailer for the generators. These vehicles completed the meticulously prepared 1,750-kilometre transport to Mürzzuschlag in 46 individual journeys.

Longest transporter: 78.5 metres

The total weight of the heaviest convoy was over 130 tonnes (tower components), and the longest transporter was 78.5 metres long (rotor blades). All convoys were just under five metres wide and about four to five metres high. Together with support vehicles for safety, the heavy transporters reached the transfer point in Mürzzuschlag after three to four nights of driving. A 400-tonne crawler crane awaited the wind turbine components there. The fact that this crane is drivable allowed best possible use of storage space to be made. A 220-tonne telescopic crane and a 7.2-tonne telehandler provided assistance.

16 per cent gradient

The components were transferred to a variety of machines suitable for mountain transport: ten-axle self-propelled trailers with and without blade devices, four-axle all-wheel drive traction units plus five-axle heavy duty modules, three-axle all-wheel drive traction units with ballast trailers (for towing) and all-wheel drive traction units with loader cranes and flatdecks. One wind turbine component after another, in order of assembly, was carefully brought up the mountain on gradients of up to 16 percent. Transporting the over 60 metre-long rotor blades, in particular, demanded the utmost concentration from the Prangl team.

600-tonne crawler crane

On arrival at the construction site 1,600 metres above sea level, pre-unloading was done by two 200-tonne telescopic cranes. A 600-tonne crawler crane was selected for the assembly work itself, because only after set-up – which, incidentally, took place under the most difficult conditions because of the mountainous location – was driving to the lifting position possible. Another 200-tonne telescopic crane served as an auxiliary crane. The modular steel towers were pre-assembled using a 160-tonne telescopic crane and a 100-tonne telescopic crawler crane. The second crane was especially important, given the need to travel with loads.

Heaviest lift: 72.7 tonnes

The wind turbines were assembled piece by piece. The “lightest” parts to be lifted were the 21.8-tonne rotor blades, while the heaviest were the 72.7-tonne tower components. Thanks to the Prangl team’s all-round know-how, the construction work progressed rapidly. Finally, the wind turbine hubs reached a height of 110 metres, and they should be commissioned by the end of the year. The Pretul II Wind Farm’s operator estimates that the turbines will be able to supply about an extra 39 million kWh to the electricity grid.