Tetrahedron has won Windpower Monthly’s innovation of the year award for its novel cranes that can install the next generation of 12-20-MW offshore wind turbines. The cranes can upgrade existing wind turbine installation vessels with minimal modification to the hull or be installed on new ones.
A key criterion for the selection of Tetrahedron for the award was efficient force flow through the crane structure. This translates into an ultra-high lifting solution offering about an extra 50 metres 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 twenty to 25 years.’
Different wind turbine installation vessel types
As the crane can be used to upgrade existing wind turbine installation vessels (WTIVs), it allows non-competitive vessels to be upgraded with an investment that is said to be one fifth the cost of a new unit. For units as small as the Seajacks Zaratan, the 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, according to Tetrahedron.
Designs have been developed to fit on tubular-legged jack-up vessels such as the Ziton Wind Enterprise and ZPMC Torben. Another design can accommodate a split jib, 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, the company can also accommodate units with lattice legs that require a large opening in the slew platform, allowing vessels like the DEME Apollo and Innovation, Teras Sunrise, Seajacks Scylla and Fred Olsen’s Blue Tern to be upgraded economically.
Picture (top): Tetrahedron configured around a tubular leg of a compact jackup (such as the Seajacks Scylla, Ziton Wind Enterprise, ZPMC Torben, and so on).
Tetrahedron crane configured around a tubular leg with a jib-split to stow the jib around the front leg (such as existing jackups: 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, and so on).
Tetrahedron crane configured around a lattice leg and with a jib split to store the crane around the front leg – here installing a 20 MW turbine (suitable to upgrade jackups such as the DEME Innovation, Teras Sunrise, Seajacks Scylla and Fred Olsen’s Blue Tern and so on).