With a couple of years of experience operating service operation vessels (SOVs) on offshore windfarms Siemens is looking at ways to reduce the cost of operations, fully utilise the vessels it has on charter and enable them to provide O&M services on more than one windfarm.
In a recent blog, René Cornelis Wigmans, head of maritime and aviation solutions at Siemens Wind Power said: “We were the first OEM to offer these so called ‘floating warehouses’ for far-from-shore windfarms. Now, after months spent familiarising ourselves with this new concept, we are looking at new ideas to enhance utilisation of SOVs through vessel sharing.”
Traditionally, vessel sharing involves an agreement between partners in a consortium to operate a liner service along a specified route, using a specified number of vessels. Now, it seems, Siemens is looking at doing something similar, and has initiated a project to determine how a fleet of SOVs could be shared between multiple offshore windfarms to maximise vessel utilisation.
Mr Wigmans says that, since SOV operations got started two years ago, SOV performance has been higher than expected. “This means that the SOVs assigned to specific sites are not being fully utilised to their full potential,” he says, which opens up a raft of options to make even better use of them.
“We are running a project to develop a roadmap to increase the utilisation rate of SOVs,” he explained. Siemens believes that sharing ships between windfarms would help reduce the cost of doing so to each. Currently, the project is focusing on shared charters for SOVs between windfarms off the coast of Sylt in northern Germany, where a couple of projects are in operation. “In layman’s terms,” he said, “the project aims to increase SOV utilisation to its full potential, reduce costs associated with offshore logistics and increase SOV flexibility to promote a ‘multi-farm’ set-up.”
In the past, SOVs were designed for use on specific offshore windfarms, but Mr Wigmans and his colleagues believe that relatively small design changes could be used to adapt vessels to meet the demands of multiple windfarms.
The kind of design changes he has in mind include adaptations in respect of the height of monopiles on different windfarms, tidal variations, and the ability to carry tools and spare parts for more than one type of wind turbine, should the need arise.
“The unique design and structure of SOVs would need to be modified to a more open approach,” Mr Wigmans said, noting that – at the moment – the scope for using first-generation SOVs on more than one windfarm is limited because they are of windfarm-specific design.
To be able to service more than one windfarm, SOVs would need to have more flexible equipment such as gangways so that a vessel could service turbines with different types of monopiles or jackets and cope with tidal variations across windfarms.
“Increased SOV utilisation has its risks,” said Mr Wigmans. “It might put pressure on resource allocation and on service technicians and materials if a vessel was put to more than one use. If utilisation increased, room for further improvement may be difficult to achieve if vessels are already working at full capability. Nevertheless,” he said, “opportunities for SOV sharing are definitely there.”