As the trend towards energy consumption continues to increase world wide, renewable sources such as wind power can help meet growing demands. Floating wind power offers a unique opportunity to generate electricity from stable winds further away from shore, and out of sight, in deeper waters. Yet, this solution still requires a cost-breakthrough to bring down the levelized cost of energy (LCOE) for these wind farms. Part of the cost reductions will come from economies of scale as developers build larger multi-gigawatt floating wind farms. However, these huge endeavors come with new challenges including optimal mooring designs, mitigating site-specific installation challenges, and overcoming lagging infrastructure and port-side access for larger installation vessels.
At DSM we believe that reaching commercial scale requires close collaboration between all members of the floating wind industry. That’s why our engineering team is extending an open offer to cooperate with system designers to engineer floating wind farms that strike the optimal balance between reliability and cost-effectiveness.
The following three examples highlight how such cooperation is already leading to lower project specific LCOE.
Principle Power: Lowering installation costs for mooring system
For Principle Power Inc’s semi-submersible projects offshore Portugal and Scotland, the mooring systems require low pre-tension by utilizing GAMA98® mooring lines made with Dyneema® DM20 fiber and manufactured by Lankhorst Ropes. The turbines reside in water depths of roughly 100 meters and the lines are attached to steel bottom chain to promote a catenary response. The WFA project team obtained the first-class certification (ABS) on HMPE fiber ropes for permanent floating wind turbine mooring systems with the support of fatigue lifetime analysis from the engineering team at DSM.
Cost reduction has been demonstrated with the use of smaller vessels with pre-existing deck handling equipment and faster pre-installation of the mooring system with no pre-stretching sequences. O&M activities are underway including fouling monitoring which is expected to further reduce maintenance costs compared to steel wire and other synthetic mooring assemblies.
Stiesdal: Optimizing Spar design with DSM’s engineering and rope performance models
“With the strong engineering support of DSM we are able to optimize our system to benefit from lightweight technologies.” - Henrik Stiesdal, Stiesdal
The stability of the TetraSpar demonstrator is ensured by a heavy keel, weighing more than 3000 tons. It is connected by 6 keel lines made with Dyneema® DM20 fiber and manufactured by Dynamica Ropes. Stiesdal utilized results from fatigue modelling by DSM to achieve the required lifetime while minimizing weight and line breaking strength. The utility of the keel lines was assessed by DNV-SE-0160 Technology Qualification methods. DSM also helped to optimize the system design of keel installation lines. The functional requirements were assessed, and recommendations were implemented to optimize the system design with minimal material use. Lastly, the mooring system also included GAMA98® mooring lines. The fatigue performance of the mooring lines was assessed by DSM to assess the design lifetime requirement of 25 years with a margin of larger than 3:1.
Glosten: Avoid costly tensioners in TLPs — Self Balancing System with Dyneema® DM20 fiber
DSM supported Glosten Pelastar in engineering a Tension Leg Platform (TLP) mooring system. Installation cost of synthetic tendons are lower than those of steel tendons. Typically, steel tendons require tensioners to mitigate load distributions caused by statically over-determined systems, unequal lengths, and constructional differences. Dyneema® DM20 fiber is engineered to self-balance loads. To fully leverage this physical feature, DSM has developed a model to determine the time required to reach a specified load sharing level – allowing TLP systems to be engineered without costly tensioners.
In summary, these three cases demonstrate the power of evaluating lightweight technologies early in the design phase. Are you interested in learning more about how Dyneema® can provide proven solutions for the lowest levelized cost of energy? If so, please contact me directly so I can put you in touch with a Dyneema® engineer to help scale your unique floating wind design.
Senior Marketing Manager