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From floating foundations to twisted jacket and Mono Bucket foundations, some of the nation’s most inventive offshore wind technologies are featured in a portfolio of advanced offshore wind energy demonstration projects that the Energy Department has been supporting since 2012.

“All of these offshore wind projects have innovative features and are among the first of their kind going through the state and federal permitting, approval, and grid interconnection processes in the United States,” said José Zayas, Director of DOE’s Wind Energy Technologies Office. “The projects are breaking new ground at virtually every step in the process, providing valuable technological advances and lessons that will benefit the development of the nation’s offshore wind industry for years to come.”

With significant resources available in the Atlantic, Great Lakes, Gulf of Mexico, and the Pacific, offshore wind has the potential to become a major source of clean energy for American families and businesses, especially those close to U.S. coastlines. As of 2015, nearly 74,000 MW of land-based wind power were deployed across 40 states—enough to generate electricity for more than 20 million households. Offshore wind resources are even stronger and blow more consistently than land-based wind resources, but have not yet been harnessed domestically on a commercial scale. 

That’s about to change, thanks to the 30-MW Block Island Wind Farm, scheduled to be fully commissioned by the end of the year, and the following three Energy Department advanced offshore wind energy demonstration projects that have made significant progress toward completion.

Fishermen’s Energy Atlantic City Wind Farm

Photo of a twisted jacket foundation.
Fishermen’s Energy plans to demonstrate the use of a domestically produced twisted jacket foundation at its Atlantic City Wind Farm, located about 3 miles off the New Jersey coast. Unlike a traditional jacket foundation, which is a trussed structure that looks similar to a massive radio tower in the water, a twisted jacket foundation features three “legs” angled around a central column. These structures are easier to manufacture and install than traditional foundations, helping drive down the cost of energy for offshore wind.

Another innovation demonstrated by this project is an access ladder designed to ensure the safety of workers who will service the offshore turbines. Fishermen’s teamed up with foundation developer Keystone Engineering to develop the ladder, which is rotated 90 degrees compared to traditional access ladders, allowing the worker to safely side step onto the ladder leading up to the turbine foundation.

Fishermen’s has nearly completed the development hurdles necessary to allow the project to be built with the exception of finalizing power offtake. The company expects the 24-MW wind farm to reach commercial operation in 2018.

Lake Erie Energy Development Corporation’s Icebreaker Project

For its Icebreaker project, Lake Erie Energy Development Corporation, a regional nonprofit corporation leading efforts to create an offshore wind energy industry in Lake Erie, plans to install six 3.45-MW direct-drive turbines on Mono Bucket foundations 8 miles off the coast of Cleveland in Lake Erie.

An all-in-one steel structure consisting of a monopile shaft attached to a large-diameter bucket, the Mono Bucket foundation is installed with a giant suction system that sucks out air and water between the bucket and the seafloor—sucking the bucket into the soil. The installation requires no pile driving or dredging, eliminating pile-driving hammer noise. Suitable for Lake Erie’s soil and winter weather conditions, the Mono Bucket foundations will reduce installation time, costs, and environmental impacts compared to traditional foundations.

Because of its location in the Great Lakes region, the project is also addressing technical challenges, such as surface icing, that are unique to freshwater offshore wind deployments.

University of Maine’s New England Aqua Ventus I Project

The University of Maine and its partners are developing New England Aqua Ventus I, a 12-MW offshore wind pilot project off Monhegan Island, Maine. Because of the project’s location in deep waters, where fixed-bottom foundations are not feasible, the University of Maine is developing an innovative, patent-pending concrete floating platform.

VolturnUS foundations will support two 6-MW wind turbines to be installed off of Monhegan Island. VolturnUS foundations were designed by the Advanced Structures and Composites Center at the University of Maine. The foundations will be held in position in the ocean by three marine mooring lines securely anchored to the seabed and connected by a subsea cable to the Maine power grid.

Rendering of a floating offshore wind turbine.

To date, the University of Maine has demonstrated a 1:8-scale prototype of this foundation and has made significant progress on the engineering design of the full-scale foundation by focusing on commercial-scale manufacturing of the foundation and reducing costs. The university has also obtained a 20-year power purchase agreement term sheet with the Maine Public Utilities Commission.

Past Projects

Although Dominion’s Virginia Offshore Wind Technology Advancement Project and Principle Power’s WindFloat Pacific are no longer part of the Energy Department-funded demonstration program, the lessons learned during the development of both projects over the past several years will benefit the burgeoning offshore wind industry moving forward.

In the second phase of the offshore wind advanced technology demonstration, Dominion Virginia Power optimized a twisted jacket foundation design for resilience to hurricanes, which will be important for future U.S. deployments on the Atlantic and Gulf coast. Additionally, the diligent efforts of Dominion and the U.S. Department of the Interior's Bureau of Ocean Energy Management (BOEM) led to the first approval of a wind energy research lease in federal waters. By pioneering the leasing process in federal waters, the project will help to inform future commercial-scale leasing processes. Dominion's development activities have also engaged industry stakeholders, leading to enhanced understanding of the unique aspects of offshore wind energy, streamlining of the permitting process, and identification of several areas and methodologies for potential cost reduction.

Also in the second phase of the demonstration program, Principle Power advanced the state of knowledge regarding floating offshore wind platforms, decreasing the weight and cost of the platform while increasing the platform turbine capacity to 8 MW. These advancements will support the next generation of floating offshore wind turbines. Principle Power also worked with BOEM to make significant progress under the BOEM permitting process; this process included extensive stakeholder outreach and consultation with local Native Americans, resulting in the enhanced understanding of the unique aspects of floating offshore wind technologies.

Through ongoing, targeted investment in research, development, and demonstration projects like these, the Energy Department will continue its work to advance the nation’s offshore wind energy industry toward commercial deployment.

Visit the Energy Department’s Wind Program website for more information on these Offshore Wind Advanced Technology Demonstration Projects.