Mammoet moves Sweden’s heaviest-ever load

Sweden is looking to increase its renewable wind energy to over 30% of its total power needs by 2024. Not only turbine components but other critical equipment such as transformers will have to be transported through some of the country’s most remote and mountainous terrain.

What is expected to become the country’s largest wind power cluster is being developed by energy company Ellevio in the remote Ljusdal municipality.  A giant 390 tonne, 750MVA transformer was needed for the project. To reach the site it had to travel over 270km of a highly challenging route. It would also represent the heaviest transport ever to travel on Swedish roads. Mammoet worked closely with freight forwarder Martin Bencher to get the transformer to site on schedule.

Strong planning was a crucial first step. Brendan James Daley, Mammoet Sweden’s sales engineer, explains: “The vast majority of roads in Sweden are not typically designed for heavy transport, and so it was crucial to have a full picture of the route from early in the project. We used planning work already undertaken by Martin Bencher and our Route Survey Tool to identify what was needed.

“The length of the route was such that a range of quite unusual preparatory work had to be undertaken. Technical assessments of road and bridge strength showed that reinforcements were needed in many places to ensure the weights involved could be withstood. In other places a 400mm depth of road had to be removed under bridges to ensure sufficient headroom.

“All of this needed to be coordinated closely to ensure the correct permits and permissions from local authorities and police were in place – not least for the four occasions where the route crossed a railway line.”

Mammoet was able to draw on its extensive inventory from across Europe for the equipment required. Power was provided by a standard prime mover supporting two 700hp Trojan trucks, capable of hauling 500 tonnes up a seven percent gradient.

The transformer was to be carried using the 400 tonne capacity AL500 girder frame, a design unique to Mammoet, that was developed specifically to allow maximum steering capabilities. This reduced the need for street furniture and obstacles to be removed along the route. The frame sat on two 16-axle trailers, with a further eight axles added under the transformer when crossing some of the smaller bridges to ensure the load was spread appropriately.

The journey began at Hitachi Energy’s facility in Ludvika, travelling 125km over two nights to reach the Baltic port of Köping, from where Martin Bencher managed marine transport north to Iggesund. From here, the final 145km route was overland. This was the most challenging section of the project as, not only are the roads smaller in this less developed part of Sweden, but this stretch also contained four rail crossings where there were strict windows during which the load could pass, as well as five bridges where the additional eight axle lines were required.

Transport was only permitted to occur at night; this meant an additional six nights were needed to reach the final destination, the wind-farm site at Tovåsen, in the centre of the country, where a second specialist Mammoet team handled the jacking and skidding of the transformer into position onto its foundation.

Despite the complexity of this project, thorough planning and close partnership between Mammoet, Martin Bencher, Hitachi Energy and Ellevio meant that the transformer arrived on site as scheduled.

A video of the job can be seen here: