There are a number of reasons offshore wind technology hasn’t caught on in the U.S. One is public opposition—or you could call it the “not in my backyard syndrome.”
That was certainly the case with the large wind farm planned off the coast of Cape Cod. Critics stated that the turbines would threaten wildlife and the aesthetics of Nantucket Sound, and many residents complained that it would drive down property values.
A second more subjective reason has been that the cost of erecting towers in water can be very expensive.
But now, the University of Maine’s Advanced Structures and Composites Center is well on the way to solving both problems.
Elizabeth Viselli, Manager of the Center’s Offshore Wind Programs and Global Communications, tells TakePart that, “About six years ago the management team here at the university and Dr. George Hart, who’s a researcher in the field of renewable energy, got together and began looking for a way for Composite Center to break into the renewable energy field.”
“We first looked at what’s Maine’s resource was for ocean energy in particular—waves, current, tidal, land-based winds, solar, and then offshore winds,” says Viselli.
“In Maine we have very deep waters very close to our shore, so the first research and development hurdle was to determine how we should respond to that. How do we access one of the best wind resources in the United States in deep water?”
Viselli explains that it’s cost prohibitive to use fixed-base technology in deep water, and that led to the idea for floating foundations.
“We came to find out after getting into it, that the oil and gas industry has been using floating platforms for years,” she says. “Of course, they’re much larger and they don’t have a large-scale area like a wind turbine on top, so there were some interesting R&D questions that arose.”
After receiving a small funding grant from their industry partner Cianbro construction, the University was awarded the first of their funding from the National Science Foundation. Then in 2008 they were awarded their first large grant from the Department of Energy for $7.1 million.
“At the awards ceremony where Department of Energy Secretary, Steven Chu announced the different winners, he charged the University of Maine with leading the nation in deep-water offshore wind technology development,” says Viselli.
“Since then, in sum, we’ve received a little over $12 million to pursue this 1/8 scale VolturnUs model that has now been deployed just off the coast of Maine and will be grid-connected on Tuesday June 11,” she says. “It’s the first offshore wind turbine in North America, and it’s the first floating concrete hull turbine in the world.”
A full-scale tower would generate about six megawatts of power and will be as tall as the Washington Monument. Viselli says that blade-to-blade, the rotor diameter will be as wide as the wingspan of a 747 jet.
“You can generate a lot of energy if they’re far out in the water, especially because of the curvature of the Earth when you’re about 20 miles out,” says Viselli. “The turbines start dropping off over the horizon, and you can’t see them, you can’t hear them, but they can still be out there generating electricity.”
After using data collected from 1/8-scale VolturnUS model to design the six-megawatt tower, the plan is for the first one of two full-size towers to be connected to the grid in 2016.
“This summer we’re spinning off a company to commercialize the technology, so it will not be University of Maine per se that operates any pilot farms and commercial projects, but rather a spinoff company,” says Viselli.
One of the most impressive aspects of the project is that the technology that’s been developed enables the towers to be constructed from low-cost, readily-available materials. “It’s concrete, so it’s inexpensive, especially compared to steel,” says Viselli.
“And the price volatility is significantly lower than steel. You don’t have to import it; it’s pretty much locally available in any geographic region, and that brings down the capital cost of the structure dramatically.”
She adds that, “The other thing that’s very interesting about this technology is that it’s constructed seaside and really the only technology you need to deploy the units is simple barges and tugboats,” she says.
“You don’t have to have specialized work boats that are very, very expensive. So whether we’re talking about the material cost, the capital cost, the mobilization and demobilization of the work boats needed to construct and deploy these floating platforms, it’s significantly lower, and that alone gets the cost very competitive if not lower than offshore wind prices in Europe.”
Viselli also says, “Furthermore, we used an advanced lightweight composite tower for the turbine to go on top instead of steel,” she explains. “Part of this has to do with operations and maintenance since a steel tower corrodes very quickly in a marine environment and the composite tower does not. But it’s also a lighter weight than steel, which means our hulls can be smaller and use even less material than you would with a heavier steel tower on top. So it’s really an optimized system price-wise, and we’re hoping to optimize it further in the next stage of the full-scale design.”
Out of sight, out of mind, and inexpensive—sounds like the perfect model for the future of offshore wind.
Do you think floating wind towers are the future of sustainable energy? Let us know in the Comments.
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