As the market for renewable energy continues to grow, the scope and scale of wind power generation is increasing. Larger, more efficient windfarms mean larger structures, with the current generation of wind turbine installations weighing thousands of tonnes each.
The Yunlin offshore windfarm is one of these new mega infrastructure projects. A 640MW development situated 8km off the west coast of Taiwan, Yunlin will be one of the country’s largest once completed. Construction is currently underway, but one of the most crucial elements of the project is actually being undertaken more than 9,000km away in northern Germany.
It’s 1am on a freezing, windswept North Sea coastline at Steelwind Nordenham – production site for some of the world’s largest monopiles. The imposing fabrication unit dominates the local skyline and serves windfarms from across the globe.
Inside the facility, the monopiles are fabricated from high-strength steel plate and now, after completion, they’ve been moved out onto Steelwind’s factory-side loading dock. It is here that enormous cranes are readying to lift the monopiles onto ships for transport by sea.
Moving these gigantic structures requires precision-engineered lifts. Each one presents a unique set of challenges for the lifting teams, who are in constant motion along the dockside making minor adjustments that will ensure the safety of cargo and crew. With the wind and rain whipping around them, they are reliant on their tools, their equipment and each other to meet the project’s strict deadlines without compromising on safety.
Looking out over the loading dock is Dr Hubo, Managing Director and Founder of Steelwind Nordenham. “Our monopiles have very large dimensions. Diameters of up to 11 metres, lengths up 90 metres and weights of up to 2,400 tonnes for a single piece.” he says.
“The key challenges are the handling of such big weights in a safe way. This is the highest priority because we have very fast loading processes and, therefore, we need absolutely safe operations.” Dr Hubo, Managing Director, Steelwind Nordenham
The Yunlin project has a tight set of deadlines which means the pressure is on to deliver smooth and effective lifting processes. With Yunlin made up of 80 turbines, the manufacturing and transportation of the monopiles is taking place all year round. This means the lifts are occurring in a variety of challenging and changeable weather conditions.
In addition, the tides at the Nordenham site mean that there are specific narrow operating windows during which the massive transport ships that are needed for this kind of job can be loaded safely before leaving with their enormous and heavyweight cargo.
“For lifting projects of this scale, the most important thing is the connection between the crane hook and the monopile,” says Patrick van der Veen, who is responsible for operations and engineering within Lift-Tex, the heavy lift sling manufacturer for the Yunlin project. Patrick shrugs off the cold as he inspects his company’s slings, ensuring they sit tightly around the massive monopile that dwarfs him and the nearby workers.
“We use Extreema® round slings for this project. This requires the lifting of 40 complete monopiles and 120 segments, so you need slings you can rely on. That’s why we chose Dyneema® SK78. It has high and consistent quality and a long lifetime that guarantees job safety. With Dyneema® you're able to make a very lightweight lifting product. This means you save a lot of time and energy in terms of handling and less weight is added to the crane’s payload.”
Light weight slings means that the lifting crews are able to easily manoeuvre the slings into the correct position around the monopile, without the need for specialist equipment and without damaging the cargo. This significantly speeds up the process as the slings must be positioned at exact placements along the monopile’s 90-metre length to ensure a safe and effective lift. This ease of use also lightens the load on workers, leading to improved safety outcomes for the lifting team.
“Dyneema® SK78 is also the best choice because of its durability and reliability,” says Patrick. “The expected service life of a sling depends on how a lifting application is designed and used, but for Steelwind, based on research in collaboration with DSM, we calculate that you can achieve at least 3,500 lifts.
“For this kind of demanding lifting operation, I wouldn’t recommend using anything other than Dyneema® SK78 fiber.” Patrick van der Veen, Operations Manager, Lift-Tex Industrie B.V.
Lifting slings made with Dyneema® perform well when compared with alternative materials and offer a range of other benefits, says Judith Bosch, Application Manager for DSM Protective Materials. “Dyneema® fiber has excellent UV performance,” she says, “and can perform in low and high temperature areas from -40°c to 70°C. If you are in any doubt about the performance of Dyneema® in high temperatures, we have Performance Models that can calculate for any application and region.”
“There are also sustainability benefits that come with choosing Dyneema®. Applications have a longer service life, yes, but we call it the greenest strength because we have the lowest carbon footprint per unit strength. We can also produce Dyneema® that is bio-based, with a commitment for 60% of production to be from sustainable feedstock by 2030.”
At the heart of everything, though, is performance – when it matters and from the very first lift. Judith explains that “Dyneema® is eight times lighter than steel, making handling much less intensive.
“Compared with polyester it's less bulky at one third of the weight and half the diameter, making it easier to handle and a better fit for the related equipment. Furthermore, it has less stretch which is very important under these conditions where precision positioning is required. When looking at other HMPE, slings made with Dyneema® have at least two times longer service life.
“The combination of reliability and long service life means lifting applications made with Dyneema® should be seen as highly valuable assets instead of consumables.” Judith Bosch, Application Manager, DSM Protective Materials
It’s now 2am, it’s started snowing and the dock is beginning to empty as the tide shifts and the window for moving these massive pieces onto the ship slams shut. With such tight deadlines and difficult weather conditions, everything must run like clockwork, every worker must be ready at a moment’s notice, and every piece of equipment must perform perfectly.
Without this trust – in the team and its tools – these kinds of heavy lifting projects would be impossible and the promise of a new era of wind power would seem very distant.
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