Offshore wind installation vessels – a coming shortage

As turbines grow in size, few vessels in the worldwide fleet can accommodate them.

Large wind power installations offshore the United States and around the globe are growing in size and scope. Also growing is the size of the turbines being used to power renewable electricity. This state of affairs may soon pose a problem, unless the fleet of vessels capable of installing these giant offshore wind turbines grows substantially.

In the U.S., the passage of the Inflation Reduction Act (IRA) last year represented “a game changer” for the U.S. wind industry, said Marcelo Ortega, a renewables analyst at Rystad Energy, a research firm headquartered in Oslo. “The tax credits in the bill for capital investments and production are designed to build and strengthen a domestic supply chain by encouraging domestic manufacturing and raw material sourcing from the U.S. or countries with a free trade agreement.”

Bigger Blades and the Supply Chain

But one supply-chain element not addressed in the IRA involves the growing size of offshore wind turbines being deployed and its impact on the required capabilities for installation vessels. According to a Rystad Energy report, the average capacity of wind turbines globally, outside of China, has grown from three megawatts in 2010 to 6.5 megawatts now, with 10 megawatts being the largest in current operation. Turbines larger than eight megawatts accounted for 3% of global installations between 2010 and 2021; Ryland forecasts that proportion will surge to 53% by 2030.

Today’s offshore wind projects are increasingly calling for 15-megawatt turbines. In the U.S., Empire Wind, located offshore Long Island, will be generating a capacity of over two gigawatts with the installation of 138 15-megawatt wind turbine generators. In the United Kingdom, the Hornsea 3 project, 75 miles off the coast of Norfolk, will have a capacity of nearly 3 gigawatts, and will consist of 231 15-megawatt offshore wind turbines. The Nordseecluster project, in the German North Sea, with a capacity of 1.6 gigawatts, will require the installation of 104 offshore wind turbines, also of 15-megawatt capacity.

“As operators continue to favor larger turbines,” the Rystad report said, “a new generation of purpose-built vessels is required to meet demand.”

Only a handful of vessels worldwide can currently install turbines of over ten megawatts. According to Rystad, the demand for offshore wind will outpace the supply of capable vessels as early as next year, as “demand for offshore wind turbine installation vessels worldwide, excluding China, will rocket from 11 vessel years in 2021 to almost 79 vessel years by 2030. The need for installation vessels for turbines larger than 9 megawatts, which was nonexistent in 2019, will grow significantly by the end of the decade and reach 62 vessel years in 2030.”

The turbines at both Hornsea 3 and the Nordseecluster will be installed by Havfram Wind, an offshore wind construction company headquartered in Oslo, which will, in both cases, be using a newly built NG20000X Jack-Up Wind Turbine Installation vessel with a 3,250-ton crane. The NG20000X has the capability of installing offshore wind turbines with a rotor diameter of nearly 1,000 feet, as well as monopiles weighing up to 3,000 tons at water depths of up to 230 feet.

Patrick Harnett, a vice president at Ørsted, the Hornsea 3 project developer, said that use of the NG20000X brings a “cutting-edge vessel to the offshore wind market.”

Maersk Supply Services

Maersk Supply Service, which has the contract to install the turbines for Empire Wind, has designed and commissioned a new and patented wind installation vessel that, it says, will make the installation of bottom-fixed offshore wind turbines up to 30% faster than the conventional jack-up method. Maersk Supply’s plan is to have the installation vessel stationed permanently at a wind farm to carry out successive installations, while two new-built tugs and barges will ferry the turbine components to the installation site. Construction on the first such vessel began late last year and is expected to be delivered in 2025.

The fact that the installation vessel stays on-site for assembly, while the tugs and barges shuttle back and forth with the turbine components, is the key to the efficiency that the Maersk Supply design is promoting, according to Jonas Munch Agerskov, the company’s chief commercial officer. “The new feeder solution equips Maersk Supply Service with a methodology that ensures a radically more efficient installation,” he said, “which will, in turn, enable developers to release their supply chains more quickly and lead to faster revenue generation from their wind farms. All of this will contribute to bringing down the costs of offshore wind.

“This methodology enables the installation vessel to be deployed solely for the purpose of the turbine installation,” Agerskov added, a characteristic which also makes the operation compliant with the Jones Act, since the vessel won’t be transporting cargo between two U.S. locations. The tugs and barges for the Empire Wind project will be built in the U.S. and operated by Kirby Offshore Wind, a Houston-based company.

In April, Maersk Supply Service announced it had entered a cooperation agreement with GustoMSC, a Dutch engineering firm specializing in offshore units, to design wind installation vessels for the European market. The process for its design, which will be built on the same characteristics as the feeder concept for the U.S. installation, is expected to be completed this year.

“Against the backdrop of growing turbine sizes,” said Nils van Nood, GustoMSC’s managing director, “we aim to further improve installation efficiencies and development economics in the bottom-fixed offshore wind market.”

Since the installation vessel does not sail into ports, added Agerskov, “this can solve some of the bottlenecks we currently see in Europe, where only a few ports are large enough to handle the growing wind turbine sizes.”

Van Nood’s comment shines a light on the logistics problem identified by Rystad facing the global offshore wind industry, while and Agerskov’s identifies yet another potential challenge. It remains to be seen whether the fleet of installation vessels will grow sufficiently to meet the burgeoning need—Havfram Wind recently ordered only its second NG20000X—and whether ports will be able to efficiently accommodate increased offshore wind installation activity and the increasing size of its components.