By Ramona du Houx

May 30, 2013

Cianbro CEO Peter Vigue, Dr. Habib Dagher and UMaine President Paul Ferguson discuss the VolturnUS offshore wind turbine project collaboration. Ferguson called the offshore wind effort a prime example of “remarkable research enterprise” that has given the university global status as a research hub. Photo by Ramona du Houx

The University of Maine recently unveiled the unique design behind VolturnUS, their patented offshore wind turbine, which will be deployed later this month. The floating hallow concrete/composite foundation of the VolturnUS is the only one of its kind in the world.

The VolturnUS unit will be assembled at Cianbro, in Brewer. On May 31st this prototype will be towed down the Penobscot River, by a crew from the Maine Maritime Academy to a spot off the coast of Castine where it will be moored- to become the first floating wind turbine in the United States. The waters off Castine are ideal for a test site because the waves are about one-eighth the height of the waves in the Gulf of Maine where full-scale turbines will eventually be positioned. By June 3, the prototype will be hooked up to the grid and providing electricity.

The goal for Dr. Habib Dagher, who leads the effort as director of the UMaine Advanced Structures and Composites Center at the University, is to get the cost of offshore wind energy down so it competes, and eventually out competes, with energy generated from fossil fuels.

“In Europe offshore wind costs twice as much as wind energy harnessed on land. The purpose of VolturnUS is to bring that cost down. Our shared goal with the Department of Energy is to get the cost to ten cents a kilowatt-hour by 2020. It’s key to the whole project,” said Dagher. “VolturnUS brings down the cost to the point where it competes with fossil fuels.”

To achieve the cost effective goal Dagher’s team had to innovate and create a new floating offshore wind turbine and platform design.

“In Europe offshore wind turbines have a life of about twenty to thirty years. The VolturnUS has a hundred year life expectancy. That’s why we developed the concrete base,” said Dagher at the Offshore Wind Laboratory in the university’s composite center.

Other elements that make VolturnUS more competitive compared to other countries that are developing offshore wind technologies were incorporated into the final design of the 65-foot-tall turbine prototype, which is a one-eighth-scale version of a 6-megawatt full-scale turbine that will be deployed 20 miles off Maine’s coastline in 2016.

“It’s like a tri-marine boat. It floats on three outer arms and the frame carries the load of the turbine. Our engineers made sure it could “breathe” in a balanced way so as waves hit the structure it has the flexibility to take on some of that impact,” said the chief engineer in charge of offshore structural design, Antony Viselli. “I have a team of drafters, modelers, and other engineers who pulled together this design concept and then worked with Ciambro’s team to make it a reality.”

Ciambro is an engineering construction company that partnered with the university to fabricate VolturnUS. The design parameters for the UMaine team called for a plan where they had to develop a stable yet flexible platform and turbine, which could withstand the wind, waves and weather conditions of floating in deep waters of the coast. The entire unit also had to be compact enough to be launched from a shallow port, and cost competitive.

“It’s a balance where you have to meet the design criteria but also keeps your cost down. That was a hard nut to crack. The design makes it the most stable offshore floating wind turbine in the world. It can also be launched in a shallow port. And all the materials used in the fabrication are local which keeps the costs down significantly,” said Viselli, who has a civil engineering degree from UMaine and obtained his Masters working for Dagher. “Floating offshore wind turbines are a big item of research. Japan, Norway Portugal and Italy are developing the technology.”


VolturnUS 1:8, will be the first grid-connected offshore wind turbine to be deployed off the coast of North America. This is the floating platform. The red portion is the waterline. Photo by Ramona du Houx

In the most competitive countries large cranes lift the turbines onto specially designed ships. Once over the desired location they drive their platform bases into the ocean floor with heavy drilling equipment and again use the cranes to lift the turbines into place. All the while they have to calculate environmental fluctuations in the ocean and air.

The VolturnUS floats. It has mooring lines with self-embedding anchors, like ships. It’s simply towed out to sea, drops its anchors and is ready to be plugged into the grid. If a turbine needs work, it can be towed back to shore, where repairs will be less costly.

“Compared to what Europeans are doing pounding a twenty foot diameter pile into the ocean bed it’s like micro surgery,” said Dagher.

With thirty local corporate partners that have been taking part in the fabrication and deployment of the technology Maine companies and UMaine expertise could lead America’s floating offshore wind development.


“It’s like a tri-marine boat. It floats on three outer arms and the frame carries the load of the turbine. Our engineers made sure it could “breath” in a balanced way so as waves hit the structure it has the flexibility to take on some of that impact,” said the chief engineer in charge of offshore structural design of VolturnUS, Antony Viselli. Photo by Ramona du Houx

“We can keep the jobs here by using Maine technology, Maine materials, and Maine people. We can manufacture the hulls in Maine and ship them to the Mid-Atlantic States and other places,” said Dagher. “If we do this first and get ahead of the competition then we can sell the electricity first to the entire New England region. It could be another major natural resource we could export creating thousands of jobs.”

Officials predict that a full scale VolturnUS wind farm could bring $20 billion of private investment to the state and create thousands of jobs.

“They will really become cost effective when we begin to manufacture them like boats in larger numbers,” said Dagher.

The long-term project—

Researchers at UMaine have been working on developing offshore wind technologies as soon as the first data came in about Maine’s offshore wind potential.

“We have 156 gigawatts of offshore wind within fifty miles of our coast. That’s the equivalent of 156 nuclear power plants worth of wind energy blowing off the coast of Maine,” said Dagher.

In 2009 The Director of the Department of Energy, Dr. Steven Chu visited the university to see the research underway and said, “I’m impressed.”

He was so impressed that after an extensive review the DOE gave the first of many grants to the university to continue its research and development offshore wind project. Previously, Dr. Chu had advised Dagher to visit Norway, with Governor John Baldacci, to see the world’s first floating offshore wind turbine. That Governor’s trade mission lead to a Memorandum of Understanding with the Norwegian company to share the technology with UMaine. While the Norwegians continue to pursue their designs, and have permits for a prototype to be deployed off Boothby, UMaine developed the VolturnUS, which is significantly different.

f973ded901aef19a-w747-199x300The full size offshore wind VolturnUS turbines will be taller than the Washington Monument. The turbines will be over 600 feet tall. This diagram shows a 747 on one of the wind blades to show the size comparison. Photo by Ramona du Houx

“The Norwegian design requires a 300 foot draft so you couldn’t really launch it from shore and it requires heavy lifting equipment, which adds to the cost significantly,” said Dagher. “VolturnUS is easily fabricated dockside and only needs thirty feet of draft, that’s a big deal. And launching VolturnUS will be as easy as launching a ship. We will be able to tow a unit out with a tugboat at two miles an hour, and it will be twenty miles offshore in ten hours.”

In 2012 the DOE gave the university a $4 million grant to help fund the installation of a pair of 6-megawatt turbines off Monhegan Island by 2017, which would create an operational wind farm called Aqua Ventus I.

By 2030 about 170 turbines will be positioned about twenty miles offshore in deepwater where the winds are the strongest and where the structures won’t be visible from land. The university has a team of top biologist conducting environmental tests to make sure marine wild life is not disturbed by the turbines presence.

“They will be bigger than the Washington Monument,” said Dagher.

A 6-megawatt unit’s rotor diameter will be one and a half football fields tall and produce fifty megawatts of electrical energy. These VolturnUS turbines will have blades longer than the wingspan of a Boeing 747.

The DOE $4 million grant could be the first of many as it makes the composite center a finalist for up to $47 million more that would be awarded during the different phases of the project. Also the state of Maine will be awarding the university voter approved bond funds for the fabrication of the Mohegan turbines.

Long before the DOE’s involvement the Baldacci administration saw the potential of offshore wind creating jobs and helping to lesson Maine’s dependency on oil. To kick-start the project the Maine Technology Institute awarded the university multiple research and development grants.

d3aae69ebb817c8c-whabibplat-247x300Dr. Habib Dagher, who leads the offshore wind effort as director of the University of Maine’s Advanced Structures and Composites Center said VolturnUS brings down the cost of offshore wind to be competitive with fossil fuels. Photo by Ramona du Houx

Then by executive order Baldacci created The Ocean Energy Task Force, which included experts in the field, lawmakers and environmentalists. In 2010 one of the laws they developed, with the approval of the Public Utilities Commission, set standards and a goal for 5,000 MW of offshore electricity to be harnessed by 2030. The task force recommendations also streamlined Maine’s wind regulatory permitting process.

“The Ocean Energy Task Force worked for a year and a half to develop the five gigawatts by 2030 plan, that’s the equalivant of harnessing five nuclear power plants worth of energy by 2030,” said Dagher. “And the legislature’s vote was unanimous.”

In edition the state established new requirements in 2008 for the Maine Renewable Portfolio Standards (RPS) which now requires each competitive electricity provider to supply 10 percent of their retail sales from new renewable capacity resources by 2017.

Stability in government policies is paramount for investors. Having the entire Congressional Delegation support the project has been a millstone and helped with obtaining DOE grants.

“We’re very grateful for the bipartisan support,” said Dagher.

It’s best to learn to walk before you run—

The VolturnUS took time to develop and showcases the ingenuity, foresight, dedication, and professionalism of Dagher’s team.

A windblade is positioned where an eventual turbine will sit. This portion of the platform will then be mounted upon the floating “trimarine.”Maine has 156 gigawatts (GW) of offshore wind capacity within 50 miles of its shores and a plan to deploy 5 GW of offshore wind by 2030. The 5 GW plan could potentially attract $20 billion of private investment to the state, creating thousands of jobs. Photo by Ramona du Houx

“It took six years looking at designs, optimizing, modeling, and testing different units. We tested a 1/50th scale unit extensively in the water,” said Dagher. “Finally we knew that we had found the solution.

A 1/50 scale turbine is about the size of a person.

“The testing work at the 1/50th scale determined which kind of design was best for the life of the turbine, it kept the turbine in a manner of speaking from experiencing sea sickness,” said Viselli.

That stability is key for a platform design that is predicted to last a hundred years at sea. Data collected from sensors on the Castine based prototype will be used to implement any design alterations to VolturnUS. The mini-turbine will be deployed for the summer and then brought in for more evaluation. It will be launched again in the winter.

“In the winter the waves get up around three to five feet and those will be interesting wave events for the structure,” said Viselli.

Researches intend to use this prototype for multiple tests before producing the bigger units.

“It’s best to learn to walk before you run,” said Dagher.

His step-by-step approach has been successful so far. He attributes that success to his team of about 140 researchers, many of them are students, and the university’s partnerships with different organizations, businesses and government enteritis.

“We’re on the verge of a new era of renewable energies and technologies – ours will help get us there. Everybody here believed in it and in the future of the technology for our nation,” said Dagher. “We are like the people who built the first pulp and paper mill in the state. When it was built people couldn’t’ imagine what would happen.”

A UMaine student won a competition to name the turbine VolturnUS, which happens to be the name for the Roman God of the eastern winds.

The VolturnUS technology is the culmination of more than six years of collaborative research and development conducted by the UMaine-led DeepCwind Consortium. The DeepCwind research program is a unique public-private partnership funded by the Department of Energy, the National Science Foundation-Partners for Innovation, the Maine Technology Institute, the state of Maine, the University of Maine and more than 30 industry partners.