Offshore Wind Infrastructure: Foundation Engineering, Submarine Cables, and Port Upgrades

Something significant is happening off the coasts of Virginia, Rhode Island, Connecticut, and New York right now. As of mid-2026, three major offshore wind projects are in active construction in U.S. federal waters, with one of them, the Coastal Virginia Offshore Wind project, set to become the largest offshore wind installation in the country at 2.6 gigawatts. Revolution Wind is 93 percent complete and has been delivering electricity to the New England grid since March 2026. Empire Wind 1 is more than 60 percent built.

Offshore wind infrastructure doesn't get the same public attention as the turbines themselves, which are visible from shore and have become part of the coastal landscape conversation. But the engineering underneath them, and between them and the grid, is the part that determines whether the whole system actually works. The foundation design, the submarine cable layout, and the port infrastructure that makes construction possible are each significant engineering undertakings on their own. Together they represent a new frontier of civil and ocean engineering that the United States is only beginning to develop domestic expertise in.

This post covers how each of those three components works, what the engineering challenges are, and what the current state of U.S. offshore wind construction tells us about the infrastructure the country is building.

1. Foundation Engineering: Keeping a 14-Megawatt Turbine Upright in the Ocean

An offshore wind turbine is an unusual structure from a civil engineering standpoint. The tower, rotor, and nacelle assembly that sits above the waterline can stand 500 feet or more above the sea surface. The rotor blades sweep an area with a diameter that can reach 820 feet. And the entire assembly produces a very large horizontal force from the wind that the foundation has to transfer into the seabed without allowing the structure to tip, slide, or vibrate in ways that would fatigue the steel over its design life. It's more like designing a tall flagpole in a hurricane than like designing a building.

The appropriate foundation type depends primarily on the water depth and the seabed conditions at the project site. Engineers working on offshore wind have settled on a hierarchy of foundation types that maps fairly cleanly to those variables.

Monopile foundations: the workhorse

Monopile foundations dominate offshore wind globally and are used on most U.S. Atlantic Coast projects, where water depths are generally less than 30 meters. A monopile is exactly what it sounds like: a single large-diameter steel tube driven into the seabed, with the turbine tower attached at the top through a transition piece. For the 14-megawatt turbines going into the Coastal Virginia project, monopiles are driven into the seabed approximately 27 miles offshore. Modern monopiles for large turbines have diameters of 8 to 10 meters, weigh up to 2,000 metric tons, and require specialized hydraulic impact hammers or vibration-assisted installation equipment to drive them to the required embedment depth.

The engineering challenge with monopiles is that they are moment-resisting foundations: they transfer the enormous overturning moment from wind loads laterally through the soil rather than through axial compression. This makes them sensitive to the stiffness and strength of the seabed soils in the upper 20 to 30 meters, and makes geotechnical site investigation, particularly in identifying and characterizing any soft or variable soil layers, critical to the foundation design.

Paulsboro Marine Terminal in New Jersey is being converted from a petroleum terminal specifically to manufacture monopile foundations at scale, targeting production of at least 100 monopiles per year. The first monopile for a project came off that line in 2023 for the now-cancelled Ocean Wind 1 project. The terminal will serve Atlantic Shores, Attentive Energy Two, and Leading Light Wind once fully operational.

Jacket foundations: for deeper water and softer seabeds

Jacket foundations are the tripod or four-legged steel lattice structures familiar from offshore oil and gas platforms. They transfer loads through multiple pile connections to the seabed rather than through a single large monopile, which makes them stiffer, more tolerant of variable soil conditions, and capable of performing well in deeper water. Empire Wind 1, which sits in water depths that exceed practical monopile range, uses jacket foundations. The engineering tradeoff is that jackets require significantly more steel and more complex fabrication than monopiles, and their installation requires different, often more specialized, marine vessels.

Floating foundations: the next frontier

Beyond about 60 meters of water depth, both monopiles and jackets become economically and technically impractical. Floating foundations, which keep the turbine upright through buoyancy, ballast, and taut mooring lines or tendon connections to the seabed, are the solution for deep water. The United States has significant offshore wind resource potential in deep water off the Pacific Coast and in parts of the Gulf of Maine that can't be accessed by fixed-bottom foundations. Floating offshore wind is still in the demonstration phase domestically, with pilot projects in development, but it's the technology that will eventually allow offshore wind to reach the full breadth of its U.S. resource potential.

2. Submarine Cables: Moving Power from the Ocean to the Grid

A wind turbine generates electricity. Getting that electricity to where it's needed requires cables: first between the turbines within the wind farm (inter-array cables), and then from the offshore collection point to the onshore grid (export cables).

The Coastal Virginia project's cable system gives a sense of the scale: approximately 200 miles of 66 kV alternating current inter-array cables connecting the turbines to three offshore substations, and around 350 miles of 220 kV high-voltage AC export cables running from those substations to the onshore grid connection.

The choice between alternating current and direct current for the export cable is a function of distance. AC works well for projects within roughly 80 to 100 kilometers of shore, because the electrical characteristics of AC cables are manageable over that length. Beyond that distance, the reactive power losses that accumulate in long AC cables make high-voltage DC transmission more efficient and more economical. As offshore wind projects move farther from shore to access stronger and more consistent wind resources, HVDC systems become increasingly attractive despite their higher upfront cost.

Cable installation engineering

Laying submarine cables is not like laying buried cable on land. The cable has to be deployed from a specialized cable-lay vessel, continuously fed off a large spool as the vessel moves at low speed. At the cable landfall, where the cable comes ashore, the transition from the marine environment to the buried onshore environment is the most engineering-sensitive portion of the route: wave action, sediment movement, and the concentrated mechanical stress of the bend at the cable entry point all create conditions that require careful geotechnical assessment and protective installation methods, including horizontal directional drilling or conduit to protect the cable below the surf zone.

At the offshore substation, the inter-array cables from multiple turbine strings are aggregated, the voltage is stepped up for the export cable run, and the electrical monitoring and control systems that manage the wind farm's output are housed. The offshore substation platform is itself a major engineering structure, sitting on a jacket or monopile foundation, weighing several thousand tons, and housing high-voltage electrical equipment that has to function reliably in a marine environment with no easy access for maintenance.

3. Port Upgrades: The Infrastructure Behind the Infrastructure

Building an offshore wind farm requires ports. Not ordinary container ports, but specialized heavy-lift facilities capable of receiving the enormous components that make up a modern offshore wind turbine and staging them for offshore installation.

A single nacelle, the housing that sits at the top of the tower and contains the generator and drivetrain, weighs 300 to 700 metric tons depending on the turbine design. Blades are 100 meters or more in length. Transition pieces connecting the turbine tower to the monopile can weigh several hundred tons. Handling and storing this equipment requires heavy-lift cranes, reinforced quayside structures that can support the concentrated loads of heavy equipment staging, and long, deep quays that allow installation vessels to berth and load without obstruction.

The South Brooklyn Marine Terminal, a 63-acre former industrial site on the waterfront in Brooklyn, is being redeveloped specifically to serve Empire Wind 1 and subsequent New York offshore wind projects as an assembly, operations, and maintenance hub. The Port of New London's State Pier served as the assembly base for South Fork Wind. The Port of Paulsboro Marine Terminal on the Delaware River has completed its Phase 1 transformation into a monopile manufacturing facility.

These port investments reflect the broader industrial ecosystem that offshore wind requires: not just the installation vessels and the turbines, but the manufacturing and staging facilities that allow them to come together efficiently. Building that ecosystem from scratch takes time and capital, and the U.S. is doing it simultaneously with the early construction of the first commercial-scale projects, which adds complexity to an already technically demanding sector.

Policy Uncertainty and Construction Progress

The Trump administration's January 2025 leasing and permitting freeze created real uncertainty in the sector, but the projects already under construction continued through a combination of legal protection, prior permits, and the practical reality that stopping partially built offshore infrastructure is far more costly and complicated than completing it. Equinor secured a preliminary injunction allowing Empire Wind 1's offshore construction to continue after a federal lease suspension. Revolution Wind reached 93% completion and began grid deliveries in March 2026. The projects that had already reached financial close and commenced construction are completing. New projects in the development pipeline face a more uncertain federal permitting environment.

Conclusion

The first generation of large-scale U.S. offshore wind projects is in the water now. The foundation types that work in the water depths off the Atlantic Coast, primarily monopiles for shallow-water sites and jackets for deeper ones, are proven technology with established supply chains. The cable systems that move power from the turbines to the grid are engineering projects in their own right. The port infrastructure that makes construction possible is being built out in parallel. The engineering challenges are real but solved. The policy and supply chain challenges are the ones that will determine the pace of what comes next.