Tetrahedron’s Offshore Wind cranes today won Windpower Monthly’s innovation of the year, selected for their novel cranes that can be used to both upgrade existing and be installed on new Wind Turbine Installation Vessels to meet the installation challenges of the next generation of 12 – 20 MW offshore wind turbines.
A key criterion for the selection of Tetrahedron for the award was efficient force flow through the tetrahedron crane structure, which translates to an ultra-high lifting solution offering an extra ~50 meters of lifting height over alternative solutions on the same vessel while lifting performance is preserved. As highlighted by Windpower Monthly, “The innovation could hugely contribute to continued deployment of many early installation vessels, which for a sound business case should remain in active service for 20 – 25 years”.
While there is significant interest for new builds, the crane can also be used to upgrade existing wind turbine installation vessels, allowing non-competitive vessels to be upgraded to install up to 12-20MW turbines with an investment 1/5th the cost of a new unit. For units as small as the Seajacks Zaratan, 12-20MW capable cranes can be installed with minimal modification to the hull, as the novel design results in lower load moments on the hull even compared to the existing, smaller cranes currently installed.
Jack-up vessel upgrades in practice
Designs have been developed to fit on tubular-legged jack-up vessels such as the Ziton Wind Enterprise and ZPMC Torben (see figure 1). Tetrahedron has also developed a design that accomodates a split jib (see figure 2), perfect for units such as Van Oord’s Adventure and Aeolus, Jan de Nul’s Taillevent and Vole Au Vent, DEME’s Sea Installer and Sea Challenger, and Fred Olsen’s Bold Tern. Lastly, Tetrahedron can also accommodate units with lattice legs that require large a opening in the slewplatform (see figure 3), allowing vessels like the DEME Apollo and Innovation, Teras Sunrise, Seajacks Scylla and Fred Olsen’s Blue Tern to be upgraded economically to meet the future challenges of the Offshore Wind industry.
The upgrades represent an attractive business case for existing operators and new entrants, especially when feeder solutions are considered, which require large lifting heights without a large focus on deck space, and with minimal investment allow existing non-competitive installation vessels to re-enter the construction market and compete with expensive new builds.
About Tetrahedron company
Tetrahedron is a young Offshore Wind Engineering company in Rotterdam, the Netherlands. The design of the crane is completed and verified by DNV GL and is prepared for delivery and upgrade executed in Rotterdam. The company is led by Wilco Stavenuiter, a 12 year veteran of the Offshore Lifting industry, and supported by a strong engineering team led by Alexander Ronse.