Mammoet has delivered the components for a 234m-high prototype wind turbine – the tallest in the world – to the Drantum II wind farm in Denmark, where the company was also tasked with removing an old wind turbine from the site.
The Siemens SWT-3.15-142 prototype has a hub height of 165m – making it the tallest onshore wind turbine design in the world – and is equipped with a 3.15MW output nacelle and lightweight 69m-long carbon blades that make it especially suitable for sites with at low wind speeds.
As a logistical operation, the project presented Mammoet with a range of challenges that are increasingly common to the industry – in line with the trend for wind turbines with progressively greater hub heights and rotor blade lengths.
First, the heavy lifting and transportation specialist was required to design two custom support frames to ensure that the lightweight blades were kept structurally intact during transit.
Secondly, the limited available space on site also meant that not all components could be delivered in advance, and so Mammoet provided just-in-time delivery of the components over the course of the de-rigging of the old turbine and the installation of the new prototype.
For the final stretches of the journey, Mammoet also had to lay down iron mats to disperse the weight of the delivery convoys and prevent soil compaction as they crossed the agricultural fields in the immediate vicinity of the wind farm.
Moving forward, Mammoet has ambitious plans to radically overhaul the erection and service of large wind turbines through the introduction of specialised cranes that will use the same mast as the wind turbine to support themselves during assembly and maintenance operations.
Mammoet is planning two initial units: the WTA 250 for assembling wind turbines by lifting mast, nacelle and blade components of up to 250 tonnes in weight, and the WTM 100, designed to service wind turbines by delivering parts of up to 100 tonnes.
Even with this system, however, the challenges associated with the delivery of wind turbine components to site will only intensify as the wind turbines themselves grow in height.
The current tallest wind turbine in the world is the Nordex 3.3MW, which, with a total height of 230m and a hub height of 164m, rests on a hybrid mast with a 100m concrete tower bottom and steel tubes on top.
The previous tallest wind turbine in the world was the 220m-high Vestas V164, which was constructed in Østerild, Denmark in 2014 with a steel tube tower, and which also has a hub height of 164m.
The Drantum II project was carried out on behalf of wind energy consortium Uhre Wind Power.
