Boom times ahead for US offshore wind fleet

A giant wind turbine installation vessel (WTIV) taking shape at the Brownsville, Texas, shipyard of Keppel AmFELS will be one of the first of a vast fleet of new offshore vessels servicing the dramatic and unprecedented US$109Bn expansion of the US offshore wind industry.

Costing around US$445M, the 144 m-long, 56-m-wide and 11.6-m-deep WTIV is being built for a Dominion Energy-led consortium and will be one of the biggest of its kind when launched in 2023.

The Jones Act-compliant vessel, to be named Charybdis, will be put into service as quickly as possible, probably on US East Coast projects, and Dominion Energy is confident it will be fully booked through to 2027. Built for the current and next generation of turbine technologies, the vessel will be capable of handling turbine sizes of 12 MW or more, according to Dominion Energy.

Meantime, the global OSV fleet is racing to help America meet the Biden administration’s ambitious targets for fixed and floating wind power. As a report from the Special Initiative on Offshore Wind makes clear, a couple of decades of work lies ahead for OSVs of all types in the US offshore wind market. “We forecast there will be 32,352 MW of contracted offshore wind power by 2030,” the report says. “Collectively, these state commitments are equivalent to the electrical capacity of 32 large nuclear power plants, an extraordinary capex that requires many suppliers.”

The numbers are off the scale: in order for the US to meet just its 2030 target, an avalanche of components will be required from the supply chain, including more than 2,057 offshore wind turbines and towers (US$43.9Bn); more than 2,110 turbine and substation foundations (US$17.0Bn); more than 8,000 km of export and array cables (US$12.9Bn); and more than 53 offshore and onshore substations (US$10.3Bn).

And according to the report’s authors, these estimates are conservative. They do not, for instance, include rapidly developing port infrastructure nor the construction of vessels needed specifically to build and maintain offshore windfarms.

“State commitments are equivalent to the electrical capacity of 32 large nuclear power plants”

ABS – which is busy classifying numerous OSV designs including Charybdis and the first Jones Act-compliant service-operation vessel (SOV) to be built by Edison Chouest Offshore (ECO) for Ørsted and energy group Eversource – identifies a range of necessary vessels, including; OSVs, SOVs, cable layers, floating heavy-lift ships, high-speed crew transfer vessels including mono and multihulls, surface-effect ships and hydrofoils, survey vessels and dredgers, a variety of barges including crane barges among others. It is an indication of the rush to acquire a role in the explosion of offshore windfarms in US federal waters that designs are pouring in from a number of European as well as American firms hopeful for contracts.

In its 2020 Offshore Wind Report – positioning for US expansion, ABS calculates that globally the total number of vessels required to support offshore windfarm installations will increase by an astonishing five times by 2025 compared with 2018, a rate of growth of over 70% a year. And it is inevitable that a disproportionate number will end up in US waters.

Although a lot of new vessels will be needed, modifications of existing ones will plug some of the gaps. “From the existing fleet, high-specification subsea vessels can be modified by adding the walk-to-work offshore access gangway [and] additional extensive modifications such as accommodations that will be needed to convert OSVs to support offshore windfarms,” the report says.

Mostly through partnerships with US companies, European operators are queuing up to get in on the action. Ørsted and Eversource already have two installations, respectively at Block Island off of Rhode Island and coastal Virginia, the latter completed in 2021, in water depths of between 20 and 28 m. Ørsted is also waiting on a variety of permits for other areas. Shell has teamed up with Portugal-headquartered EDP Renewables for contracts, notably for Mayflower Wind, an 804-MW project 32 km south of Nantucket. Mayflower Wind recently signed a letter of agreement for the construction of a Jones Act-compliant hybrid-battery diesel-electric CTV. And Iberdrola took control in September 2021 of two wind projects in Connecticut and Massachusetts respectively that will require their own fleet of OSVs.