Heavy-haul trucking …
To where the wind blows
Towers and rotor blades for wind turbines.
To maximize wind power harvesting, the size of the blades and towers of modern wind power systems keeps growing – and so does the complexity of hauling them.
Tower segments and rotor blades from Vestas Wind Systems had to be hauled inland across a roughly 100-kilometer (62-mile) distance from the Swedish port of Gävle to Hedemora (small pictures). In Madeira (large picture) elements for three large-scale wind turbines were hauled from Porto Caniçal across half the island to the hilly hinterland surrounding the town of Ribeira Brava.
The extremely long blades (84 m/275 ft) and voluminous tower elements (diameter of 6.3 m/20.7 ft) required two different routes in Sweden, along which traffic circles had to be superstructed, high curbs banked up and traffic signs and lights removed. For the haul, the tower segment was fixed in place on the front and rear chassis using tube adapters, enabling the transportation of segments with a maximum weight of 110 metric tons (121 short tons) and diameters of up to 6.8 meters (22 feet). At the rear chassis, six steerable axle modules ensured high maneuverability.
For transporting the rotors, Goldhofer developed two systems. In Sweden, “Blades” was used. There the rotor blade base is fixed in place in a special swiveling mount installed on the tractor, while the rotor tip sits on a trailing dolly. For particularly winding roads, such as those that had to be mastered in Madeira, Goldhofer has a heavy-duty module called FTV on offer that even has self-propelling capabilities in very narrow sections. Its highlight: The module is designed for not only enabling freely suspended transportation of the rotor blade but also for lifting it by up to 60 degrees. As a result, the rotor tip just sweeps across obstacles if necessary. By the way, with a length of 67 meters (219 feet) the rotor blades hauled in Madeira were “small fry.” Lengths of more than 84 meters (275 feet) are possible, according to Goldhofer.
70-meter (230-foot) lindworm
Three transformers for the substation of an offshore wind farm.
The energy transition toward renewable sources entails a decentralization of the grid infrastructure. For that purpose, plants such as new substations have to be established around the globe.
To make the energy generated by the 950-MW Moray East wind farm off the coast of Scotland available to consumers as 230-volt electricity, a substation with three transformers, each weighing more than 260 metric tons (286 short tons) and nearly twelve meters (39 feet) long, was built up-country near New Deer. The transformers had to be hauled across a 56-kilometer (35-mile) distance full of hills, corners and bridges from the port of Peterhead to New Deer.
The lateral beam bridge “Faktor 5.5” that was used can take up cargo with a width of up to six meters (20 feet), a length of 17 meters (56 feet) and a weight of up to 350 metric tons (385 short tons) and flexibly move it thanks to load leveling and 1.6 meters (5.2 feet) of hydraulic lift height. Since the transformers were 90 metric tons (99 short tons) below the maximum weight it was possible to use a configuration of “only” 10 axles per side at the front and rear. That made the 70-meter (230-foot) lindworm relatively agile.
Tons of cable
Cable drums for building power lines.
Transporting electric power generated by photovoltaic systems or wind turbines to where it’s needed requires cables – very long cables. Depending on the cable design and length (currently up to two kilometers/1.2 miles), the drums currently weigh 55 metric tons (61 short tons) – which may increase to 100 metric tons (110 short tons) in the future. Accordingly, the width of the drums of four to five meters (13 to 16 feet) today will increase to eight to twelve meters (26 to 39 feet). To make matters worse, the heavy-duty trailer (the picture shows a so-called vessel bridge hooked up between two heavy-duty modules that carries the cable drum) has to be suitable for difficult off-road conditions at construction sites. The use of self-propelled units is possible and increases the trailer’s flexibility.
To handle the increasingly voluminous cable cargo, Goldhofer’s experts are currently developing an optimized vessel bridge to accommodate an unwinding device for drums weighing up to 100 metric tons (110 short tons). Concurrently, concepts are being developed for motors with synchronized drive for jerk-free cable unwinding at the installation site.
Mega tank truck
Overflow tanks for a solar farm.
In 2005, Solarpark Bavaria in Germany with 10 megawatts (MW) was the world’s largest solar farm. Today, the Mohammed bin Rashid Al Maktoum solar farm already has a capacity of 800 MW to be expanded 5,000 MW or 5 gigawatts in the final stage. To supply energy around the clock, solar power stations convert the energy of light not only into electric power but also store it in the form of heat, for instance by heating thermal oil. Huge overflow tanks are part of this complex heat cycle.
A total of 30 tanks with a length of 52 meters (171 feet) and a weight of 235 metric tons (259 short tons) each had to be hauled from the port of Jebel Ali in the United Arab Emirates to the solar farm in the desert of Dubai. The greatest challenge was precise adherence to the tight completion schedule for the solar farm. For this, the route and loading times had to be optimally planned.
One by one, the tanks were loaded onto 30 heavy-duty trucks that embarked on their journey in convoys of two. To pull the mammoth load of 235 metric tons (259 short tons) per truck through the desert sand, the weight was distributed to no fewer than 30 axle lines per side. After their journey, the tanks traveled another distance of about 100 meters (328 feet) on the hook of a 400-metric ton (441-short ton) crawler crane before being installed on previously prepared foundations. The advantage in the desert: There were no narrow bends to be mastered, so the tanks could be transported on a continuous heavy-duty module despite their length of 52 meters (171 feet). When the trucks have to go around corners, the situation gets trickier. But even that is possible as the picture above of a tank with a length of 60.5 meters (198.5 feet) being hauled in Texas shows.