Offshore wind power prototype goes online
It may sound like a phrase from “Star Trek,” but with that command, shouted at sea, history was made Thursday in Castine Harbor.
For the first time ever in the Americas, an offshore wind turbine provided electricity to the power grid after a University of Maine floating prototype was powered up.
“This is a historic moment for the Americas,” said professor Habib Dagher, director of the university’s Advanced Structures and Composites Center, which designed and built the turbine with the assistance of Cianbro Corp. and dozens of other public and private partners.
After the command was given, a worker on VolturnUS powered up the 57-foot tower. The blades turned to face the wind and slowly started to rotate. Within minutes they were rapidly spinning along, powering the 20-kilowatt generator atop the tower.
Dagher and a coterie of faculty and students from the university joined officials from Maine Maritime Academy, Cianbro and a gaggle of reporters aboard The Ned, MMA’s 80-foot research vessel, at the site off Dyce Head where the turbine, VolturnUS, has floated offshore for about two weeks.
The turbine is a one-eighthscale version of the full-size turbines UMaine plans to place in the Gulf of Maine by 2016. By 2030, the university hopes to install about 170 6- megawatt turbines, each taller than the Washington Monument, with blades longer than the wingspan of a Boeing 747. Each turbine would provide enough electricity to power about 2,000 homes, Dagher said.
The VolturnUS model powered up Thursday in Castine provides enough electricity to power only about four or five homes. But that didn’t make Dagher any less proud of the milestone moment, which comes six years after the wind project began at UMaine.
“You’ve got to crawl before you can walk, before you can run,” he said.
Maine is home to more than 156 gigawatts of offshore wind capacity, according to university research. Peter Vigue, CEO of Cianbro, said the design, construction and deployment of VolturnUS signals to businesses that Maine is serious about developing its offshore wind portfolio.
“This should give the state of Maine a tremendous amount of credibility within the renewable-energy community on a global basis, and convince people this is a place to invest,” he said.
Dagher said that in the two weeks since Maine Maritime Academy tugboats towed the tower from Brewer to Castine, researchers had been running tests and observing the tower to see if it would behave as their modeling suggested.
So far, everything has gone off without a hitch.
To see the turbine sitting in 80 feet of water, one might not know it was floating. It has been designed with three concrete hulls that keep it stable, and care was taken to ensure it wouldn’t react to even the largest waves it might face.
Dagher said the largest waves in Maine, which occur during a 100-year storm, are about 60 feet tall with a wavelength frequency of about 17 seconds. VolturnUS won’t respond to any frequency less than 25 seconds.
The biggest test for VolturnUS took place while it was being towed to Castine. Dagher said that a storm brought 4- to 6-foot waves. Dagher said that because the turbine is a one-eighth-scale model, that’s the equivalent of the full-size turbine standing up to 32- to 48-foot waves.
“That’s a hurricane-type wave,” Dagher said. “This unit saw its equivalent, and while the trailing tugboat was swaying back and forth, it was barely moving.”
The VolturnUS project is an effort to create offshore wind in a more cost-efficient way than has historically been done in Europe, Dagher said. At offshore wind farms there, each turbine is drilled into the seabed, a process requiring marine construction, massive specialized equipment and a lot of money.
VolturnUS — a blend of the words “volt,” “turn,” and “U.S.” as well as the name for the Roman god of the easterly wind — was built in Orono, assembled in Brewer and towed fully constructed to its destination. Dagher said because the turbines can be built on land and towed back for maintenance, the price drops dramatically compared with the cost of drilling turbines into the sea floor. He expects each full-scale version to last 75 to 100 years.
The one-eighth-scale version in Castine will be tested for about a year. By 2016, the Advanced Structures and Composite Center hopes to have two full-size turbines in testing off Monhegan Island. Design for those turbines is currently under way at UMaine.
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