Orca Offshore has successfully concluded the modeltesting of the Monobasewind concept.
Monobase Wind BV project director Jan Groot Monobase said: "All tests were in line with our predictions for all stages of the transport, installation and in-place situations."
Highlights of the tests include:
- The transportation analysis showed mild accelerations (less than 1.1m/s²) at nacelle height, even at 6m significant wave height (12m maximum waves). This is due to the own period of the Monobase being greater than 20s; the first order movements are therefore not sensitive for waves in the southern part of the North Sea (mostly 4s-8s waves)
- The Monobase also moves within acceptable limits during the installation procedure, with wave limits of 2m (10s) and/or 2.5m (8s). This will allow the operational crew to choose the weather window with the required flexibility. In practice, the operational crew may choose a lower wave height, but these tests show the redundancy in design and procedure.
Specifically, the lowering of the ‘donut’ was much more controllable than expected. The donut slows down several metres before engaging with the tower mat and gently sets itself on top of it. The deceleration can be designed for any specific circumstances by tuning the space between the donut and tower column
- The in-place simulated a 100-year storm in 45m water depth, resulting in massive maximum waves of 32m, which were withstanded by the Monobase without problems. This should give future clients the confidence that the Monobase can be designed to withstand the heaviest storm conditions
The next stage for the company is to execute detailed studies for clients and to design the Monobase for specific locations, environmental conditions and turbine specifications.