Seajacks harnesses wind for growth
Wind turbine installation vessels (WTIVs) may not be a familiar sight on the high seas as yet, but, with government subsidies fuelling growth in this renewable energy source, you can expect a few more to blow onto the industry horizon in the near future.
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Gunvor Hatling MidtbøVice President, Communications
REFINING THE CONCEPT
Seajacks encouraged operational employees to provide feedback based on their experience on the two first WTIVs in the Seajacks fleet. These suggestions were then reviewed and, where appropriate, included in the final specifications for Zaratan. This process of steady refinement corresponds with Seajacks’ rig building philosophy – namely that quality and reliability trump, what Alcock calls, “Innovation for innovation’s sake.”
“There’s always a place for innovation, but it needs to be based on a solid framework. When it comes to rigs, the most important thing is a sound and workable design. Once you have that, then you can start to think about refinements.
“We learned a lot when constructing and operating our previous two rigs, which are similar, but smaller than Zaratan. The modifications that came out of that process were incorporated into the design and we are looking forward to seeing a better end-result,” he says.
As wind installation vessels are generally contracted on a day rate, huge losses are incurred if a vessel is out of commission due to technical failure. This is why Seajacks has a strict list of pre-approved suppliers, focusing on quality and reliability.
“Being closely involved on the engineering side throughout the project has allowed us to guide decisions, leading to a better final product” - Tor Martin Flåten Senior Project Manager, Kongsberg Maritime
FEWER SUPPLIERS
Many builders pride themselves on employing an army of mini-suppliers, billed with developing individual parts. Seajacks, however, finds this approach difficult to manage and fraught with danger. Instead, explains Alcock, they prefer to work with fewer, trusted suppliers.
“It’s one thing to have good parts, but integrating those parts can be problematic. You reduce this risk when you work with a small number of sub-contractors responsible for handling large parts of the project. For example, GustoMSC designed the basic vessel structure, the jacking system and the crane – if we had purchased each of those parts from different suppliers, integration would have been more difficult,” he says.
In line with this approach, Kongsberg – in conjunction with Norwegian Electrical Systems – is supplying, sub-contracting and integrating all the electrical and automation apparatus on the vessel as well as delivering engineering services throughout the project. According to Senior Project Manager, Tor Martin Flåten, the combination of delivering a complete package and transparent cooperation with the other partners enables Kongsberg to deliver an excellent service.
“We are delivering our entire range of products and services on this project. That, combined with the close partnership we have shared with the other stakeholders from the start of the project, provides us with a great opportunity to deliver an excellent service. Being closely involved on the engineering side throughout the project has allowed us to guide decisions, leading to a better final product,” he says.
ACCURATE POSITIONING CAPABILITY
Installing offshore wind turbines requires extreme positioning accuracy. That is not easily achieved in the North Sea, especially in winter – leading some to question wind-farm installation as a viable year-round activity. In addition to the operational equirements, Alcock says Zaratan’s fully redundant Dynamic Positioning 2 (DP) propulsion system makes economic sense, as it shores up any possible contractual obligations due to safety requirements.
“The nature of wind-farm installation makes a robust DP system essential for safe and effective operations. Indeed, you can’t win contracts unless customers know your rigs have a strong DP capability. With regards to the seasons, we’ve found that the weather is not as problematic as has been predicted; Zaratan is purpose built for such conditions. We also monitor weather patterns carefully and have the possibility of jacking up and riding out bad weather, if necessary,” he says.
AFTER CONSTRUCTION
Seajacks Zaratan will be delivered in May 2012. The rig will then be taken – by heavy lift transport – to Rotterdam, where it will mobilise for a contract with WindMW GmbH to install a new wind farm in the German sector of the North Sea. Seajacks Leviathan is also contractedfor the same project.