8 MW Offshore Wind Turbine Installation With a Self-propelled Jack-up Vessel

Abstract

Recent developments in sustainable energy industry show a trend where larger wind turbines, which are also often located in more challenging environmental conditions, are taken into usage to produce energy. This matter sets new requirements on previously used technology, as well as for the vessels specialized for mounting offshore wind turbines (OWT). Installation of the OWT is most commonly made feasible by using a jack-up vessel – a floating vessel fitted with powerful crane and vertically liftable support legs. High stability under external loads and accuracy during the installation process make this kind of specialized vessel hardly replaceable despite of its complicated design. Determining the performance of the jack-up vessel is a sizeable and several factor dependant task, that in general terms could be classed as response durability in different operation modes and structural design reliability of special parts. In order to characterize more 8 MW equivalent size OWT installation, the focus of this work is set on jack-up vessel crane lifting response analysis (primarily dynamic hook load determination) with corresponding input data. In addition, main environmental loads as well as load responses are described and a brief overview comprising of recent developments in the industry is given. One main purpose of the work is to bring out possible obstacles, which one may encounter when installing bigger OWT than in normal practice till now has been done. To give work more practical value, analysis are done based on the requirements and recommended practises of DNV-GL. For obtaining numerical results, as well as illustrating the discussions, relevant software is preferred. This kind of practical orientation approach should contribute the utility of the inferences and help interested parties to efficiently eliminate certain technical matters encountered so far. The work is composed in view of the production possibilities and preferences of the CRIST S.A. in Gdynia, Poland.