The biggest, heaviest, and most delicate lifts in Dominion Energy’s Coastal Virginia Offshore Wind (CVOW) development are not the components for the 176 wind turbines, but the three 4,000-ton (3,629-tonne) offshore substations.


DEME Orion

“The first is scheduled for installation on foundation in the fourth quarter of 2024,” Christopher A. Nunn, director of engineering and onshore construction for CVOW told HLFPI. “The remaining two substations will be placed on foundations in the second quarter of 2025.”

Dominion is coordinating with DEME Group on the shipment and placement of the substations on their foundations, Nunn added. “The Orion is the vessel that I understand will be setting the substations.” He spoke with HLFPI during a site inspection to Dominion’s two pilot turbines, installed 25 miles (40 km) off Virginia Beach in 2020. The USD9.8-billion CVOW commercial development will be 27 miles (43 km) offshore, with an installed capacity of 2.6 GW.

Orion made news when delivered in May 2022 for its 5,000-tonne lift capacity HLC 295000 crane made by Liebherr, the largest crane that manufacturers has ever built. Orion will also handle the installation of the foundations for the turbine monopiles. The monopiles will descend about 120 ft (35.5 m) into the seafloor.

CVOW Pilot Turbine Transition Piece close

Source: GDLM

The turbine towers, nacelles, and blades will be installed by Dominion’s own newbuild installation vessel Charybdis, which is being built at Keppel AmFELS in Brownsville, Texas. It is scheduled to be launched by the end of the year and will be the first US-flagged offshore wind energy installation vessel. Deck area will be 58,000 sq ft (5,388 sq m), presided over by a main crane with a 426-ft (129.8 m) boom and a 2,200-tonne lift capacity.

The first charter for Charybdis will be out of New London, Connecticut for a pair of wind-power developments off New England by Ørsted and Eversource. Starting in the third quarter of 2025 it will build CVOW out of the wind-turbine manufacturing and marshalling facility under construction at the Portsmouth (Virginia) Marine Terminal.

Construction season for CVOW runs from May 1 to October 31, so as not to interfere with the migration of endangered northern right whales. The blades are 354 ft (107.9 m) long and, when mounted, will reach a maximum vertical height of 837 ft (255.1 m) above mean sea level.

thumbnail_CVOW Pilot Turbine sun

Source: GDLM

The substations are to be supplied by Bladt/SEMCO, said Nunn. “Fabrication of topsides structures is primarily being done in Spain by Tencate and Navacel. The topsides will be shipped to Denmark where Bladt/SEMCO will complete fabrication, installation and testing of all systems during the harbor acceptance test. The current estimated total weight of each substation approximately 3,928 tons (3,563 tonnes).”

Nunn added that he is sent frequent updates on the weight of the substations as fabrication advances. As noted, DEME will be responsible for transportation and installation.

Prysmian Group, based in Milan, is responsible for the inter-array cables from the turbines to the substations, and the ocean export cables, from the substations to the landing station ashore.