The growing need for offshore vessels means €2.4 billion in investment is required over the next decade, according to estimates from the Community of European Shipyards Associations (Cesa) and the European Wind Energy Association (EWEA). The two bodies have warned that a lack of vessels could delay the delivery of offshore wind.
"CESA and EWEA are asking the European Commission and European Investment Bank to help stimulate the funding of new ships to build and service offshore wind farms," said CESA. It sees the number of heavy-lift vessels deployed in European waters rising from nine this year to 16 in 2013.
Developers agree that more vessels are needed. "Offshore wind is going to need ten to 12 new heavy-lift vessels, foundation vessels and ships to transport towers, nacelles and blades," said Eddie O'Conner, CEO of Mainstream Renewable Power. The sector will also require more workboats.
There are growing calls for the design and procurement of offshore vessels to be improved, with more consideration given to the operational cycle of winds farms and fuel efficiency, as well as cost effectiveness during the post-warranty phase. "The offshore wind sector needs vessels that have a multi-role capability," said Stephen Bolton, director of operations and maintenance at Offshore Marine Management.
Others agreed, foreseeing a range of changes from the forthcoming generation of offshore vessels. "We expect that, in the future, not only size and fuel will have to be looked at but also comfort when onboard, maintenance cost and repair cost," said Kaj Lindvig, chief sales officer at wind-farm operator A2Sea. "We will see several new vessel designs depending on area, access, local sea states and distance to shore."
Bolton expressed concern that sufficient improvements in vessel design may not emerge as long as turbine makers dictate the terms. "Continuing to allow vessel manufacture to be driven by the needs of turbine manufacturers alone could mean that not enough attention is paid to the full maintenance requirements of an offshore wind farm," Bolton said. "We need to manage the entire wind farm, not just the turbines, and we need to look at the 20-year life cost, not just the first five years.
"This includes the inspection, maintenance and repair of the subsea infrastructure — namely cables, cable-protection systems and foundations, not to mention offshore substations and their particular needs," he added. "For a small impact on design and cost this additional capability could be included. The sector needs vessels designed for all the developer's requirements."
Instead of producing ships that have just one function, such as accommodation vessels, designers could combine this primary role with a capability to carry a complement of 30-40 technicians with a full dive and remote-operated-vehicle capability. This would mean that vessels could carry out a number of functions more or less simultaneously, reducing the requirement to charter multiple single-use vessels.
An example of such innovation is the Sea-Wind WMV, a concept developed by Anglo-Dutch company Offshore Ship Designers. Described as a "mother ship", the Sea-Wind WMV would be a multi-functional vessel acting as a "harbour" for smaller work boats and as a floating heliport. According to Neil Patterson, managing director of OSD-IMT, Offshore Ship Designers' UK arm, the vessel will service up to 45 turbines a day while accommodating the workforce.
The fuel efficiency of offshore service vessels is another key issue, said Bolton. "When offshore turbines reach the end of their warranty period, operation and maintenance costs will be scrutinised and become crucial," he said. "Fuel burn is a through-life cost and is going to become more important."
More fuel-efficient vessels are able to move through the water with greater ease, often thanks to more streamlined hulls and lower weights. Ships offering greater fuel efficiency are being developed by companies such as Incat Crowther and BMT.
Cesa agrees fuel efficiency will be a growing priority. "Our view has always been that the priority must be vessels which will perform soundly and operate cost effectively over their lifespan," said a spokesman. "Aside of reducing fuel costs, wouldn't it be a paradox to have a polluting vessel working in the renewable-energy field?"