Increasing distance will boost case for vessel specialisation

WORLDWIDE: Up to now much of the shipping used for offshore wind has been designed based on experiences gained from the offshore oil and gas sector. As offshore wind heads further from shore a more customised fleet with novel access technologies will be required

It is clear that moving into deeper and further-from-shore waters is almost as big a logistical step up as moving from land to near-shore waters was a decade or so ago. Transferring people, equipment and components to a site more than 200 kilometres from shore – which is the distance from shore of a large portion of the North Sea's Dogger Bank Round 3 development zone – would involve facing waves pitching up at 2-3 metres.

This represents a very different challenge to dashing from port to nearby wind site and back in a day.

The remoteness and scale of the next generation of offshore wind farms will require stationing people at the site on a permanent, rotating basis. This applies to both the construction phase as well as for maintenance activities over a wind farm's operational life span.

Whether this is done through the use of large "mothership" bases or via fixed accommodation platforms remains an issue for debate. Both options may have their merits, as does the use of helicopters to augment vessels for rapid access and in conditions that vessels cannot operate.

As well as the accommodation vessel versus rig debate, there are also different schools of thought when it comes to the use of specialised vessels versus multi-functional ships capable of carrying out a number of tasks simultaneously. Specialisation is likely to dominate the construction phase of offshore wind, with vessels designed for specific tasks, such as underwater exploration, foundation construction, tower installation and cabling seeing, ongoing design enhancements.

The operational and maintenance phase may be more appropriate for the deployment of multi-functional vessels.

Much time and money has been spent developing foundation, turbine and cabling technology for deployment at sea. Similarly, research and effort has gone into designing next-generation vessels aimed at delivering more efficient, safe and cost-effective solutions for deployment in deeper water and further-from-shore locations. Many of these new vessels have yet to be built. It is up to the wind industry to ensure it has the transport in place that will ensure that expensive offshore assets are not only built effectively, but also maintained around the clock in increasingly hostile and distant environments.