WTIV newbuild dilemma – will wind turbines continue to grow?

In an interview with Seatrade Maritime News, Geir Fuglerud, Director of Offshore Classifications – Maritime for DNV, highlighted how fixed bottom offshore wind turbines had grown to 11 - 15MW and could continue to keep growing.

The WTIV market is one that the classification society sees as significant and new orders have been placed over the last two years to meet the demands of larger turbine installations as older vessels do not have the required lifting capacity.

It’s a segment where Fuglerud notes DNV has been “very successful” classing all five orders made last year. A report by analysts Rystad pointed to demand for an additional 40 – 60 WTIVs by 2030 to cater to these large turbine installations.

“The challenge that the owners are facing now is we've seen some of these units being ordered over the past few years, but where is the growth in size of the turbines going to stop?”

While currently the market is talking about 11 – 15MW turbines the question is will the size continue to grow with 20MW, or 25MW turbines in future.

Even the jump from 11MW to 15MW sees huge changes in the capacity required by the WTIV, which needs to be able to lift 20 metres higher and have a lifting capacity of 1,000 – 1,200 tonnes compared to 650 – 700 tonnes for an 11MW unit. And this is all with a tolerance of just 5 – 8 millimetres.

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If turbines do increase further to 20MW and 25MW the lifting capacities required from WTIVs would become even higher, potentially rendering new vessels ordered today obsolete.

“But the challenge they [the owners] are facing is that if they build now a unit will it become too small in five years? Will they need to convert it in five years? Will they be able to convert it given the size of the future?

“You don't want to put in $300 - $400 million into an asset that is going to won't be able to do any work in 10 years,” Fuglerud said.

One limiting fact could simply be the cost of the vessels given the deck load capacities required, heights involved, and the complexity of the cranes, which would make installations so expensive that it could curtail the growth of turbines.

“I think we're starting to see now that there seems to be an interest from the turbine manufacturers to kind of maybe standardise around 15 Megawatts.”

However, Fugerland notes that if in 10 years-time one manufacturer produces a 20MW unit, most likely everyone else in the market will follow.