However, offshore wind turbine installation vessels have different designs than in the oil and gas installation industry.
Offshore wind turbine installation units may be column-stabilised, self-elevating or ship-shaped tailor made for the installation and maintenance of fixed and floating wind power equipment. They are designed to install offshore wind turbine equipment such as foundations, columns, generator houses and blades, piece by piece by crane lifts or in one operation using lowering techniques.
“Compared to traditional oil and gas units, these vessels have a different set of safety and technical issues… This in addition to increased requests from the industry, has motivated us to launch the new class notation,” says Henning Carlsen, the business development manager at DNV’s Offshore Classification unit.
The class notification will serve as a recipe for how to class offshore wind turbine installation vessels. It is currently being piloted and is expected to be added to DNV OSS-101 by October 2009.
The rules for offshore wind turbine installation units focus on four main areas:
- General design and construction requirements for offshore wind turbines, wave power and tidal power installation units;
- Design requirements for the different types of wind turbine installation units, which include ship-shaped units, self-elevating units and column-stabilised units;
- Structural details relating to the lifting operations and the many cycles of repeated vessel operations; and
- Certification of materials and components.