Commissioning & decommissioning of wind turbines can be a very time consuming and costly business, especially offshore, when using increasingly large vessels over longer distances to transport and install components. The DOT slip joint can greatly reduce installation time when compared to more traditional bolted or grouted methods and allows for single lift turbine installation. Wind turbines can be installed in a matter of minutes with minimal preparation like putting the cap on a ballpen. This process can also be reversed making replacing or removing turbines far less complex. The slip joint concept can be used for both tower to monopile and nacelle to tower connections. Furthermore, the slip joint can also be used for sea fastening making it a highly efficient innovation for both transport and installation.
Onshore full scale testing
A fully operational 500kW hydraulic wind turbine including wind turbine control via spear valve and a slip joint was tested onshore at the Maasvlakte in the Port of Rotterdam.
Offshore full scale testing
Commissioning, operation, certification and decommissioning of the DOT turbine including a full scale slip joint and monopile installation.
- Proof of slip joint concept
- Level D, B & C type certification (DNV-GL)
- Single lift installation of a WTG in combination with a floating installation vessel
Floating installation of an XXL offshore wind turbine
Demonstrating floating installation of our large offshore wind turbine combining Heerema’s Rotor-Nacelle assembly with the slip joint technology. Successful demonstration of:
- Rotor Nacelle assembly
- Slip joint based seafastening
- Nacelle – Tower slip joint
All our innovations are supported by an extensive track record of studies, prototypes and offshore testing. Our approach is to “put steel in the water”: relentlessly testing the concepts in its designated environment of operation.