ECN publication
Offshore Wind Access 2017
Published by: Publication date:
ECN Wind Energy 5-4-2016
ECN report number: Document type:
ECN-E--16-013 ECN publication
Number of pages: Full text:
38 Download PDF  

Offshore wind farms in Europe are constantly moving further from shore in order to capture the favourable wind conditions. However, challenges regarding their Operation and Maintenance (O&M) become more prominent. Especially, transfer of technicians to the wind turbines through access systems such as Crew Transfer Vessels (CTVs) and motion compensated gangways on Service Operation Vessels (SOVs) is the most important factor of weather downtime during maintenance activities. As an indication, an access system which can provide access up to already relatively high sea states with a significant wave height of 3 m, it is restricted to an average accessibility of 70% during winter months in a typical North Sea location. This makes clear the importance of improvements on offshore wind access systems.

This report presents an overview of the current and under-development access systems, identifies their market potential and establishes a framework for evaluating their added value through ECN’s in-house developed tool “ECN O&M Access”. The ECN O&M Access tool is an O&M cost estimator specifically developed for the designers and developers of maintenance vessels and access systems for the offshore wind industry. Through this tool, vessel and access system designers and developers are able to investigate the impact of their designs/systems on the wind farm availability and maintenance costs. The results of the tool can be used to identify the drivers for the required research on access systems and the cost reductions and/or improved safety that can be realised.

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