Concentrated power for wind farm
June 20, 2017 | Markus Lackner
“We would have been ready to implement the lifting job in mid-April,” says Günther Wimmer from Felbermayr’s Project Department which, among others, specialises in multi-modal solutions for particularly heavy industrial goods. “However, due to persistent wintry conditions, the temporary road leading to the construction site could only be fi-nished in early May,” the seasoned heavy haulage expert explains.
Little wonder considering the fact that the transshipment site for the components weighing up to 67 tonnes is already located 1,400 metres above sea level. From there, a comfor- table country road of 2.35 kilometres heads off in the direction of the construction site. After that, one has to negotiate a two-kilometre logging road. The last seven kilometres to the wind power construction site 1,700 metres above sea level are covered on a temporary road. This translated into difficult conditions and great challenges that can only be overcome using special transport vehicles.
Wind power system transport equipment
However, special flatbed trucks are not just used right before reaching the construction site, but also for ground transport from the manufacturer’s factory to the transshipment site. Thus, so-called blade trailers were used to transport the 39.5 metre long rotor blades weighing in at 9.6 tonnes 1,300 kilometres. The tower segments 11.33 meters in length and 4.4 metres in diameter were transported in a self-supporting fashion using so-called tower lifters. Even double-telescoping semi trailers and semi flatbed trailers were used as convoys of up to three vehicles to transport the system parts to their destination. The 208 road transport jobs departed from Magdeburg, Aurich and Emden in Germany. Due to the delay caused by the temporary road’s belated completion, the team had to find an interim storage site as no appropriate area was available on site. They found it at the premises of Felbermayr’s heavy-load port in Linz.
Blade lifter overcomes 20-percent gradient
Even though the long-distance transports had many roundabouts and signal systems in store, transporting the components in the mountains posed the greatest challenges, says Wimmer. After all, the team had to negotiate tight corners and gradients of up to 20 per cent. Thanks to the blade lifter, the blades can be raised by 60 degrees. This makes it possible to negotiate tight corners lined with trees. Eight heavy haulage axles, pushed and pulled by two heavy haulage tractor units provide the required weight distribution and traction to drive in this difficult terrain.
Mobile crane with Y-shaped suspension to increase load capacity
Construction sites above the tree line also translate into difficult conditions for the lifting technology teams. Even for Liebherr’s LTM 1750 packing the punch of 607 horsepower, it was not easy to reach the work site 1,700 metres above sea level. The crane operator had to use all his skill, safely driving the 108-tonne state-of-the-art lifting device across the mountainous terrain. Six transports carrying 144 tonnes of crane ballast and boom elements as well as the auxiliary crane with 200 tonnes of maximum load capacity safely reached the construction site.
Following a setup time of two days, the crane was equipped with 144 tonnes of ballast and its Y-shaped suspension and ready for the lifting job. “The client had specified one week to set up one unit,” Wimmer illustrates the tight schedule. Within this time, the team had to lift into place five tower elements weighing 25.5 to 66.64 tonnes, the nacelle including hub and stator as well as the three rotor blades. “Usually, this system type’s blades are pre-assembled on the ground and attached to the nacelle using the star assembly method.” Due to, in part, very uneven ground on site, this was not always possible, however. In such cases, the three blades had to be lifted to the hub 78 metres up in the air by crane. “This requires a lot of time and stable wind conditions,” Wimmer adds. The main advantage of pre-assembling the elements on the ground, however, lies in the safety aspects as they don’t always have to be lifted to such great heights.
Despite adverse weather including driving rain and squalls, extensive effort should make it possible to finish the last system on the Handalm pasture in August, the project operators optimistically report. This is only made possible by the 29-strong Felbermayr team’s experience and that of all companies involved in the project. For even the most sophisticated technology can only perform what people request from it.
By year’s end, the 13 systems with a blade diameter of 82 metres are supposed to be connected to the grid. With their overall output of 30 megawatts, they will deliver renewable energy to some 21,000 households. This makes this wind farm the most powerful to date in Southern Austria. And yet, the project’s implementation was not only about the system’s technical data but also about strictly adhering to more than one hundred environmental requirements. This guaranteed maximum protection of the fauna and the neighbouring pastures and woods.
