Trenchless Technology 2025 New Installation Project of the Year Honorable Mention

Coastal Virginia Offshore Wind (CVOW)

Coastal Virginia Offshore Wind (CVOW) is the largest offshore wind project in the United States. Michels used Direct Pipe and horizontal directional drilling to complete a critical section of the project.

Project Background

Once complete, CVOW will generate enough energy to power up to 660,000 homes. It will add to Dominion Energy’s diverse energy mix, which is essential for energy security, reliability, and lowering fuel costs.

Michels used the two methodologies to construct landfalls and trenchless crossings of environmentally sensitive areas. This allowed them to provide electrical conduits for a 176-turbine (2.6-gigawatt) wind farm located 24 nautical miles off the coast of Virginia.

Direct Pipe was used for the nine landfall locations. These installations were mined from the beach out into the floor of the Atlantic Ocean.Ten HDDs were used to cross sensitive areas on land to install electrical conduits to house the new power cables. This is the largest number of Direct Pipe installations completed at one time anywhere in the world.

The nine Direct Pipe landfall installations placed 42-in. diameter steel casing from the beach to the ocean floor. 36-in. HDPE conduit was then pulled inside each steel conduit. Approximately 17,000 ft of HDPE pipe was placed inside the steel casing amongst the nine installations. The steel casing was then extracted, leaving the HDPE conduit in place.

Ten HDDs were performed under two environmentally sensitive areas: five under Lake Rudee and five under Lake Christine. Each of the Lake Rudee HDDs spanned 1,935 ft. Four HDDs installed 48-in. HDPE casing pipe, and one installed a 42-in. HDPE casing pipe to house the HDPE electrical conduits.

Each crossing passed about 60 ft below the existing grade. Each of the Lake Christine HDDs spanned 1,675 ft. Four HDDs installed 48-in. HDPE carrier pipe, and one installed 42-in. HDPE carrier pipe to house the electrical HDPE conduits. Bundles of HDPE conduits were then installed inside each of the HDPE casing pipe.

Why Project Is Outstanding

The project was built in an environmentally sensitive area with high scrutiny from the public. Inadvertent returns of drilling fluids to the surface at the beach area was a considerable risk. The more common method of HDD was initially considered for the landfall installation.

Typically, deeper installation is the best option to mitigate this risk with HDD. However, it was not possible in this case. Deeper installation would have had an adverse impact on the ampacity of the cable.

Employing Direct Pipe

Therefore, Michels recommended Direct Pipe as the method of choice. This allowed for the safe installation of the conduit without occurrence of any inadvertent returns. The Direct Pipe method allowed the client to move forward with the project with minimal environmental risk without impacting the capacity of the project.

Additionally, the jobsite was located within the State Military Reserve (SMR). The SMR conducts a month-long Contested Urban Environment (CUE) exercise every six months. The conditions for site occupancy included equipment and personnel evacuation from the jobsite during the exercise. This meant that after every five months, work needed to be secured and halted for a month to accommodate the SMR.

The project team was able to complete the project on time by planning the work around these shutdowns. All time-critical activities that could not be halted after starting were planned within the five-month working window.

The landfall installation included excavation of the entry pit to set up the Direct Pipe equipment. When Michels started the excavation for construction of the entry pit, it was discovered that the water table was approximately 7 ft higher than previously anticipated. This led to a change in the dewatering method.

A new industry standard was set by running three spreads of Direct Pipe crew and equipment simultaneously on a 24-hour basis. This was necessary to meet the schedule requirements. When a tunneling operation with Direct Pipe starts, it is not good practice to stop until the operation is completed.

Because the operation windows were limited, Michels’ management of multiple crew and equipment spreads helped the client keep the project on schedule.

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Project Details

PROJECT OWNER: Dominion Energy Virginia

ENGINEERS: J.D. Hair & Associates and Haley & Aldrich, Inc.

CONTRACTORS: Wilson Construction Co. (general contractor); Michels Trenchless Inc., Michels Construction Inc. and Michels Pipeline Inc. (subcontractors)

SUPPLIERS & MANUFACTURERS: Behrens & Associates, Brownline, Dominion Recycling Center, Herrenknecht, In-Terra Innovations, ISCO Industries, Sixense Inc. and United Rentals

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