Innovative crane for offshore wind turbine installation
The increasing size of wind turbine generators sets a challenge for the offshore wind installation industry. Existing jackup vessels are rapidly becoming uncompetitive because they cannot lift high enough to reach the highest parts of wind turbines. Based on a fundamentally different motion principle and an efficient structural load transfer, the Tetrahedron crane lifts higher than alternatives that can fit in the same crane footprint, offering an economically viable path for owners who want to upgrade jackups or build more cost competitive units to compete in the turbine installation market.
Jackup installation vessels owners face a multitude of risks with installing the latest 10-14MW class turbines, but if owners are unable to increase the lifting height sufficiently on existing installation jackups, their ships are at risk of becoming unusable within the offshore wind industry by 2023. Netherlands-based Tetrahedron has developed an innovative crane that can make existing jackup vessels suitable for installing the next generation of wind turbines at sea, with a design that is future-proof even for future turbine developments up to the 20MW class. The innovative crane can be retrofitted onto existing jackup vessels easily, delivering a competitive upgrade in lifting height and allowing existing vessels to compete well into the next decade. Founder and Director Wilco Stavenuiter says: “Due to its unique design and patented technology, the Tetrahedron crane simply lifts 50m higher than existing cranes, without adding any weight or complexity.” He continues: “In practice, jackups that are originally designed to install 5MW turbines can be upgraded without hull re-enforcement (due to the low moment a Tetrahedron crane exerts on the jackup) and will be able to install future wind turbines such as the SG14-222 DD or the GE Haliade-X.”
This drop-in solution on existing jackups unlocks additional earning power for jackup vessel owners. As an example, the Tetrahedron 45 can lift a Haliade-X nacelle at 40m radius, 180m above the waterline with sufficient clearances to install the blades, while still fitting on smaller jackups with minimal modification. Offshore installation contractor Van Oord, Delft University of Technology and various industry suppliers have contributed to the development of the crane in collaborative projects co-funded by the Netherlands Enterprise Agency (RVO). The concept design of the crane is completed and verified by DNV GL and now Tetrahedron company focusses on crane delivery in Rotterdam by 2022.