Feature Materials handling


The secret to handling taller turbine towers


Irish-based materials handling provider Combilift and Danish manufacturer Andresen Towers have pooled expertise to address the logistical challenges involved in manufacturing and moving extreme lengths of product for Andresen’s revolutionary new design of wind turbine tower


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ndresen Towers is part of the IAI Group which has more than 25 years of experience in producing bended and bolted steel towers. The company has recently taken its original concept a stage further with the design of patented shell towers and has secured an exclusive long-term contract with Siemens Wind Power which will sell its products. New production and warehouse facilities have been set up at Andresen’s HQ in Nyborg and Langeskov in an area of 25,000m². “In order to make wind energy a more competitive alternative to fossil energy sources we have harnessed our technology to build the next generation of much higher towers,” says CEO Tom Andresen. “These can exploit the better wind conditions to generate a larger output which in turn reduces costs. For example, an increase in the hub- height from 80m to 125m will decrease the price per KWh by 25 per cent.” The increased height of the steel shell towers compared with those cur- rently available is due to the larger diameter and the reduced material thickness allows them to be produced from steel coils. These are cheaper than traditional steel plates and result in lighter towers. No welding of the structure is required as it is held together by tension controlled bolts, which do not need any retightening after installation. Traditional tubular welded structures are limited to a diameter of 4.3m governed by the


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existing road infrastructure (such as bridge heights) when it comes to the transportation of these extremely over- sized loads. As Andresen’s shell tower sections are designed to be bolted together on site, they can be easily car- ried on ordinary trucks or in 45in con- tainers. This avoids extra costs for special transport, reduces disruption to traffic, and enables the shipment of towers to previously inaccessible areas. Having solved the problem of moving the sections to their destina- tion, a further issue was how to safely and efficiently handle and store loads which can be almost 14m long, 3.3m in diameter and weighing up to 30t in and around the production facilities. This is where Combilift came in and a two-way dialogue with Andresen’s management led to the choice of a Combilift Straddle Carrier (SC) as the one machine solution for each of the two sites. The design of each SC was adapted to take into account the slightly differing loads at Nyborg and Langeskov, the latter being built with a larger frame to cope with double stacked high cube containers. “There were a number of options open such as a combination of mobile cranes and traditional counterbalance forklifts or reach stackers, but Tom Andresen did not want to invest in pieces of equipment that could only carry out one specific job,” says Ulrick


Combilift’s Straddle Carrier has been adapted to safely handle and store loads which can be almost 14m long, 3.3m in diameter and weighing up to 30t in and around Andresen Towers production facilities in Nyborg, Denmark


Staudal of Combilift Denmark. “He was also focused on the total cost of ownership, which is becoming more of an issue for customers than just the initial investment.”


Combilift T: 07870 976 758 www.combilift.com Enter 363


A major advantage of the SC com- pared with a counterbalance truck capable of lifting the required capaci- ties is its much lower own weight and therefore greatly reduced ground pres- sure. A counterbalance truck capable of handling a 40t load will weigh at least 50t, resulting in a tonnage of 90t when loaded. This puts extreme pres- sure on the ground surface, which will need special and costly reinforcement to cope. With a weight of just 18t, the combined weight of the SC and load is just 58t, which has cut out the need for any expensive foundation work at Andresen’s sites. “Our calculations based on a 10-year operating lifetime took in initial capital outlay, fuel con- sumption, service costs and the reduc- tion in wear and tear on the surfaces and proved that Andresen could achieve major operational savings compared with using any other type of equipment,” says Staudal. “The dimensions of Combilift’s SC and its three-wheel manoeuvrability enable it to access the production area to load crates containing up to seven steel shells, weighing from 1.3t. to 3.25t each which are ready to dis- patch,” says Andresen. “The sheer physical size of a counterbalance truck would have made this nigh on impos- sible. We can then load onto HGVs without the need for a crane. In addi- tion the SC handles incoming contain- ers of components we manufacture elsewhere. The spreader beam attach- ment with different lift points also enables us to lift varying sizes of loads. Both inside and out, the SC has been ideal for our needs and an added bonus was that it was a lot more eco- nomical than any other options we looked at.”


This joint Irish/Danish project started in December 2011 and after just six months the operation is up and running. The first crate of shells for the new generation of Andresen’s towers rolled off the line, onto the SC and ready for shipment in mid June 2012.


JULY/AUGUST 2012 Materials Handling & Logistics


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