Powerful crawlers for powerful turbine

The General Electric (GE) 12MW “Haliade-X 12 MW” offshore wind turbine had to be erected on land to make access to the system easier during the test phase. The massive tower and the complete 675t gondola with its gigantic dimensions of around 1,500 cubic metres surrounding sophisticated technology was installed at the port during the summer.

Heavy haulage and special transport group Mammoet, which was awarded the erection of this wind turbine, used two LR 11350 cranes from Danish crane contractor BMS to erect the 12 Megawatt system, using tandem hoists in some cases. One of the two crawler cranes came straight from the production line at the Liebherr plant in Ehingen to the site.

Liebherr’s Power-Boom came in handy for this demanding job.  Through this system the main boom is doubled at the bottom, increasing the capacity of the lifting gear massively. The upright boom position required in Rotterdam and a boom length of 150m meant that this system increased the lifting capacity of these Liebherr cranes by over 70% compared to a standard lattice boom system.

As so often on wind power sites, the weather at the port of Rotterdam dictated the timetable for the major hoists. For example to install the gigantic gondola, the load was positioned between the two crawler cranes for more than two days until the wind conditions finally allowed them to complete the hoist onto the 150m high tower. The 675t heart of the system then required around one hour to cover the route to its final position. With the enormous special cross beams and the lifting tackle, the two crawler cranes had to manage a total load of 780t. After reaching the final height, the crawler carriers carefully started to move – the two LR 11350 cranes had to move around 20m with the load on their hooks until the gondola could be positioned precisely on the tower.

Only one of the two cranes had to remain in Rotterdam to install the 107m rotor blades a few weeks later. The system was finally completed by the end of October. According to the manufacturer, a turbine of this type should be able to generate 67GW hours of electricity every year. That corresponds to the consumption of around 16,000 households.