Worldwide energy consumption is increasing and renewable energy sources such as wind power are under huge pressure to meet these demands. As urgency grows, so must the ambition of Floating Offshore Wind Turbine (FOWT) projects.
The next step forward is the building of large multi-gigawatt floating wind farms which can benefit from stable winds, and are non-visible from the shore. Such huge endeavors come with new challenges like optimal mooring designs and overcome difficulties in the installation of multiple units at sea, especially in areas that may lack infrastructure or larger installation vessels. The biggest challenge of all is to bring down the levelized cost of energy (LCOE) of the electricity generated by these farms.
“Lower LCOE can be achieved by utilizing the unique benefits of high performance tendons or ropes made with Dyneema®.” – Jorn Boesten, Segment Manager Offshore Energy, DSM Protective Materials
At DSM, our application technical specialists and engineers can support you and co-engineer solutions to lower the LCOE for floating wind turbines and farms. Read on for examples and we welcome you to contact us for discussions.
With strong understanding in the key cost drivers in fabrication, installation, operation and maintenance such as mooring tethers for semi-submersibles, tension leg platforms and spars as well as structural components like guy and keel lines, the engineers at DSM offer support in optimizing the overall design of your floater for floating wind farms.
For Principle Power Inc’s Windfloat Altantic (WFA) floating project in Portugal and Kincardine Offshore Windfarm, the low pre-tension mooring systems are made up of three hybrid catenary mooring lines of Lankhorst GAMA98® ropes made with Dyneema® DM20. Water depth is about 100 meters and the lines are attached to bottom chain for the catenary action. With DSM’s support, the WFA project obtained the first class certification (ABS certified) on HMPE fiber ropes for permanent floating wind turbine mooring systems.
Cost reduction has been demonstrated in the design of small deck handling equipment and small size connectors, easy pre-installation of the mooring system with no prestretching and easy hook-up. The expected minimal fouling contributes to low maintenance costs.
You can find Dyneema® DM20 in the most demanding applications: mooring floating offshore wind turbines, keel lines, synthetic chains for lifting and offshore crane ropes.
Photo credit: Principle Power Inc
Photo credit: TetraSpar Demonstrator ApS
“With the strong engineering support of DSM we are able to optimize our system to benefit from lightweight technologies.” - Henrik Stiesdal, Stiesdal
At DSM, we have developed core equations and an engineering method to predict and track a rope’s lifetime as a function of its use based on tension, time and temperature (taking into account all system parameters). DNV issued a certificate of technology qualification on our core equations.
With DSM’s in-depth engineering knowledge around fiber and ropes made from the fiber, we were able to support the Stiesdal TetraSpar project with a focus on lowering levelized cost of energy in optimizing design of mooring lines by reviewing functional requirements. The mooring lines are made from Dyneema® DM20.
The stability of the Stiesdal floater is ensured by a heavy keel, weighing in excess of 3000 tons. It is connected by 6 keel lines made with Dyneema® DM20. Using DSM’s rope fatigue models we optimized the balance of required lifetime and minimum breaking strength. And contributed to certification using the DNV E407 assurance methodology.
DSM supported in optimizing the system design of keel lowering lines and hold back slings used during installation, beyond the load and safety factor. The design left limited space available and by taking into account the functional requirements recommendations were made to optimize the system design with minimal material use.
DSM supported Glosten Pelastar in engineering a Tension Leg Platform (TLP) mooring system. Installation cost of synthetic tendons is lower than that of steel tendons. Typically with a statically over-determined system and given that tendons are never equal in length, steel tensioners are required for load distribution.
Dyneema® DM20 patented engineering feature allows for controlled balancing of the load over all 5 tendons. DSM design model is used to determine time to a specified load sharing level. As such, smaller systems can be engineered and no costly tensioners are needed.
Speak with us to learn about the support you can receive from us.
Moving gigantic monopiles onto ships for transport by sea requires precision-engineered lifts. For such lifting projects, the crucial link is the connection between the crane hook and the monopile to ensure safety of the cargo and crew under time pressure.
For one of Taiwan’s largest offshore windfarms, known as the Yunlin project, Steelwind Nordenham chose slings made with Dyneema® SK78 to overcome these challenges. Dyneema® SK78’s consistent high quality coupled with a long lifetime guarantees job safety and it’s lightweight feature means increasing ease of handling and efficiency.
DSM has engineered Dyneema® SK78 fiber in such way that it offers at least twice the fatigue performance of generic HMPE fibers. At fiber and at sling level, with DSM’s Performance Model, the fatigue lifetime of a sling made with Dyneema® SK78 can be determined based on both static and dynamic loading conditions performed in any climate. These tools also help in reducing project costs.
Next to lifting slings monopiles are increasingly lashed with synthetic chain. Synthetic chains made with Dyneema® are as strong as steel but 85% lighter, and lashing speeds are twice as fast. Lightweight chains also mean that the crews securing the monopiles are able to quickly transport and maneuver the equipment into the correct position around the monopiles, without damaging the cargo or incurring the need for specialist equipment.
Not only is this safer for crews’ health and safety, but it also increases efficiency, by reducing crew numbers and operation times, which can be vast when it comes to enormous lashing operations like these.
“For us, safety is the most important thing onboard and Dyneema® is part of our safety culture, which we look to improve every day.” - Peter Mathot, Senior Port Captain, Jumbo Maritime
Our models and systems are certified by DNV and in Type Approvals by Bureau Veritas and ABS.
If you want to know more about our certifications, please contact us.
Dyneema® DM20 fiber is designed with molecular anchors to enhance lifetime performance with highest strength to weigh ratio and at near neutral buoyant (0.96 kg/l). Dyneema® DM20 fibers are widely used in synthetic chains, mooring lines and static lines under permanent load with excellent fatigue resistance, abrasion resistance and incredible durability.
Dyneema® SK78 fiber is renowned for its quality, consistency and performance. Heavy lifting slings need to be reliable in all kinds of environments and under immense pressure. From life-long tension fatigue to temperature performance, from static to dynamic loading, we put Dyneema® SK78 fiber through rigorous testing to ensure they work at their full capacity for longer and in all possible scenarios.
Get in touch with our experts. Get advice on how Dyneema® could optimize your business.