78 monopiles for Coastal Virginia OWF – Phase 1

78 MONOPILES FOR COASTAL VIRGINIA OFFSHORE WIND FARM – PHASE 1

Between May and September 2024, the CAPE VLT-640 Quad was deployed to install 78 XXL monopiles for Phase 1 of the Coastal Virginia Offshore Wind (CVOW) farm in US Atlantic waters. Each foundation measured up to 8.5 metres in bottom diameter, reached a length of up to 82 metres, and weighed up to 1,700 tonnes, making them among the largest monopiles installed in US waters to date.

Located off the coast of Virginia Beach in the Atlantic Ocean, CVOW is being developed and owned by Dominion Energy and is set to become the largest commercial offshore wind farm in the United States, with 176 turbines producing up to 2.6 gigawatts of electricity, enough to power over 660,000 homes. The 78 monopiles installed during this campaign formed the first phase of a total foundation scope of 176 piles. Installation contractor DEME carried out the offshore works from its heavy-lift, mono-hull DP3 installation vessel Orion, operating in dynamic positioning mode throughout the campaign.

The scope concerned flanged monopiles with a top diameter of 7.5 metres, a bottom diameter of up to 8.5 metres and a wall thickness of 104 millimetres. They were installed in water depths ranging from 25 to 40 metres, with a target penetration of up to 30 metres into the seabed. Ground conditions at the site included topsoil layers known to cause pile run (a sudden, uncontrolled drop of the pile during installation), which placed strict demands on installation control and safety.

The CAPE VLT was selected for two decisive capabilities. Firstly, its ability to upend each pile from a horizontal transport position to a vertical stance and position it accurately over the target location. Secondly, and critically for this site, its ability to drive the piles through the troublesome topsoil layers under full control, effectively eliminating the risk of pile run and ensuring a smooth, predictable installation sequence pile after pile.

For this campaign the system was configured as the CAPE VLT-640 Quad, delivering an eccentric moment of 2,560 kgm and a maximum line pull of 3,400 tonnes: the power and grip required to handle 1,700-tonne foundations and drive them to depth efficiently. The combination of controlled upending, precise positioning and pile-run mitigation enabled all 78 monopiles to be installed safely and on schedule across the May to September window, reinforcing the CAPE VLT’s track record on XXL monopile projects in the world’s most demanding offshore renewables markets.

Find more project details below or contact Dick van Wijngaarden for more information.