The US is going to need an estimated $22.4bn in offshore wind investment in the next seven years, but vessels are only a portion of it.

Of the total investment, roughly $3.75bn will be needed for large ships such as wind turbine installation vessels (WTIVs), heavylift ships and barges to meet the White House’s goal of producing 30 GW of offshore energy by 2030, according to figures from the National Renewable Energy Lab (NREL) included in an Evercore note following the Floating Wind Solutions Conference & Exhibition in Houston, Texas.

The $3.75bn compares with approximately $7.5bn needed for port facilities.

The remainder is for turbines, substructures, electrical components and steel plates.

US companies looking to get into offshore wind have argued they are caught in a difficult position, where developers need ships to construct the turbines, while shipowners need to see movement on projects before they will order ships.

Meanwhile, it takes shipyards several years to construct the vessels and port facilities are needed to help build the wind farms.

The NREL estimates the US needs as many as six WTIVs, but US companies have been slow to build out Jones Act-qualified versions of those ships, as they must be built domestically.

Projects can use foreign-flagged WTIVs, so long as it does not move cargo, but they do require US-built ships to transport the turbines for installation. The NREL said the US would need as many as six heavylift ships and eight feeder barges.

On ports, Florida’s Crowley has purchased land in Massachusetts for the construction of a dedicated offshore wind facility and signed an exclusivity agreement in northern California for a facility there.

At the conference, NREL said leases for floating offshore wind in California could reach 7.5 GW based on industry norms, Evercore said.

In addition to northern California, it identified southern Washington state, the Great Lakes, offshore Maine, the New York Bight and central Atlantic coast as areas with longer-term potential for offshore wind development.