Starting this spring, Castine Harbor will be the temporary home to cutting-edge wind energy technology created here in Maine. A one-eighth scale prototype of a floating deep-sea wind turbine developed at the Advanced Structures and Composites Center at the University of Maine will be placed in the harbor, just off Dyce Head, sometime in April.
The floating turbine tower has a total height of 57 feet, according to documents from the U.S. Department of Energy. Its floating radius will leave it 500 to 1,000 feet west of Dyce Head, attached to three mooring lines and anchored in 100-foot-deep water.
The windmill will be outfitted with a 20 kilowatt or 27 horsepower turbine, one of professor Habib Dagher's "VolturnUS" turbines. It's a smaller version of the 300-foot-tall floating turbines that will be tested later in the water off Monhegan Island.
Castine Harbor was the only location in the state, Dagher said, where the water and wind conditions were scaled down to offer meaningful testing at a smaller scale.
"We need to match the wave environment to the size of the unit, so it could match the scale of the unit the way the larger ones will in Monhegan," Dagher said Wednesday. "So, basically we shrunk the unit, and so we needed to shrink the waves."
The windmill and floating base are all being built at UMaine by Dagher and engineering students, the professor said. It will be shipped to Cianbro's facility in Brewer where it will be reconstructed in the Penobscot River. From there, a tugboat from Maine Maritime Academy - one of UMaine's partners in the DeepCwind Consortium - will tow the device to its moorings in Castine Harbor.
The tower will be connected via electric cable to a small outbuilding on land, where it will connect to Central Maine Power's network and provide electricity to the grid during its test run.
While the tower will be visible from land, its location means it won't be part of the view for many Castine homes and will be completely hidden from view of downtown Castine. Town Manager Dale Abernethy said he's yet to hear any grousing from residents about the tower's temporary location in his town.
"I haven't heard any complaints about it," he said Monday. "I haven't really heard any comments at all from the local folks, really."
The VolturnUS is meant to be Maine's answer to what has historically been an expensive endeavor: Harnessing the awesome power of ocean wind and transforming it into electricity.
Dagher said the reason wind towers in Europe are so expensive is the amount of equipment and materials necessary to install them. Even in the relatively shallow water in coastal Europe, the process of installing a turbine is Herculean.
"The most common design method is the mono-pile design," Dagher said. "A barge comes over and pounds a 15-20 foot diameter steel pile into the sea bed. These piles can be 120 feet long. Think about transporting something this big 10 miles off shore. Then you have to lift the tower in sections, 300 feet high above the ocean, then you have to lift the turbines. The cranes you would need, the vessels you would need, are very expensive."
Dagher's design allows the entire tower to be built on land. Because it floats, it can simply be pulled into place and anchored. Gone are the huge barges, the pile-driving ships and the complexities of oceanic construction.
The testing of a small-scale wind tower in Castine is the second phase of a five-phase plan that Dagher hopes will end with the implementation of full-scale offshore wind farms about 20 miles off Maine's coast.
Because the towers will be less expensive to produce and place, Dagher said, Maine's goal of wind energy at 10 cents per kilowatt hour could be attainable within the next couple decades.
To that end, the testing in the nearshore waters of Castine is a crucial step, he said.
"That's why we're doing this small test first: We have to walk before we can run."