Next-generation turbine installation vessels need to be able to handle 15-MW turbines, but they also need to be more environmentally friendly than their predecessors
Concern continues to be expressed that the fast pace of growth in the offshore wind industry – and in the size of offshore wind turbines – could lead to a shortage of installation vessels.
The market for vessels capable of installing large offshore wind turbines is being outpaced by growing demand from the global development pipeline, analysts suggest, such that the global fleet will be insufficient to meet demand from 2025 onwards.
More vessels need to be constructed if demand is to be met by supply: with many large offshore wind projects coming down the line, one leading analyst, Rystad Energy, expects installation vessel demand will be four to five times higher than it is today by 2030.
Several vessels have been ordered, but brokers argue that such is the fast pace of growth in the size of turbines, that owners are wary of ordering ships now that might be outdated within years of entering service. With a price tag of in excess of US$250M, owners need vessels to have a lifetime of 25 years or more.
The answer to this conundrum is what leading jack-up designer GustoMSC calls ‘purposeful design,’ which means designing future-proof vessels based on existing technology that have the capability built in to evolve and be upgraded, but do not include too much new technology, which could present risks and deter investors.
To find out more about what the defining characteristics of a vessel suited to such a fast-moving market might be, OWJ spoke to GustoMSC commercial director Jan Mark Meeuwisse. Such is the fast pace of growth in the size of offshore wind turbines that Mr Meeuwisse describes the company’s role as “trying to help owners hit a moving target.” The answer, Mr Meeuwisse says, is to ensure new vessels have sufficient ‘shelf life’ and can be upgraded later.
“When we designed Sea Installer for what was A2SEA, the vessel was intended to install turbines of up to 3.6 MW,” Mr Meeuwisse explains. “It was delivered in 2012. Turbines quickly increased in size to 5.0 MW, then 7.0 MW, 8.0 MW and more. Now we are at 9.5 MW and much, much larger turbines are coming down the line.
“We are talking about being able to lift components weighing 1,000 tonnes from the deck of a vessel, maybe more. As components get larger and heavier, so the load that the vessel’s jacking system needs to be able to cope with grows, the amount of deck space you need increases and you need to ensure the crane is still capable of accessing all the components on deck, wherever they are.
“As you move into deeper water, leg length also becomes an issue. Everything you do to a jack-up adds weight, and that weight has to be lifted out of the water. That means more wear and tear on the jacking system, which has to cope with the additional weight daily as a vessel moves from turbine to turbine.”
And the larger the vessel, the more expensive it becomes. “Above all, you have to ensure that you still have a vessel that is economic to operate, and one that is stable when installing turbines but efficient when underway,” Mr Meeuwisse says.
“The industry has known for two to three years that much larger turbines are coming. It’s no longer a ‘new’ situation, but it’s still not clear how much larger they may become. What is clear is that jack-ups are having to lift ever-heavier components to ever-greater heights and turbine blades are getting longer and longer. There is no other industry like this anywhere, where you have to lift loads of 1,000 tonnes, to a height of 140-150 m or more, in a single lift. It’s unique.
“9.5-MW turbines are not an issue for new vessels, but by 2023-24, unless there are more vessels capable of handling even larger turbines, the industry might hit a bottleneck and existing vessels might not be able to meet demand,” he tells OWJ. “And yet our clients need to know that if they order a vessel now, it won’t become obsolete in a decade.”
In a scenario like this, Mr Meeuwisse says, the ability to upgrade a vessel is essential, whether with an enhanced crane or – as the industry focuses ever-more on ‘green vessels for a green industry’ – with future-proof, environment-friendly power generation technology.
If a vessel is designed from the outset with a growth margin, upgrades are perfectly possible, he suggests, citing an upgrade Fred Olsen is undertaking to one of its Gusto 9000 jack-up vessels, installing a new crane capable of installing next-generation offshore wind turbines.
“There is also a lot of emphasis from owners on green power generation and propulsion nowadays,” Mr Meeuwisse tells OWJ. “There are a lot of ideas about, but not all of the technology is quite there yet. It’s important to find a solution that meets the requirements of a turbine installation vessel, when it is in transit, in dynamic position mode, when it is lowering or raising the jack-up legs and when it is lifting a nacelle or a tower.
“We have looked very carefully at liquefied natural gas as a fuel, but strongly believe it is not the solution. We don’t find that it is all that clean when you look at it right from source. We do however believe in fuel cells. They are not quite there yet, but we have future-proofed designs by making them fuel-cell ready.”
Exactly how fuel cells might be implemented on a vessel at a later date and when, depends on the vessel and on the availability of technology, but they could replace one of the ship’s generators, for example. Batteries are also an option, says Mr Meeuwisse. They can be used at times when peak power is required or for peak shaving, and energy generated on board can be used to recharge them. But not all markets where offshore wind is booming are ready for battery power yet, he suggests.
“If you want to take a look at the way forward, our new design for OHT is a good place to start,” Mr Mr Meeuwisse concludes. “In this vessel, some of the options that are expected to be available later have already been incorporated.
“In addition to an optimised hull shape, this vessel – the GustoMSC NG-14000XL-G – will have a battery-hybrid solution, and a specialised electrical control system to reduce emissions by 20% compared with similar-sized installation vessels. And, to further reduce its carbon footprint when in operation, it will also be prepared for the use of fuel cells powered by hydrogen.”