Promise of Offshore Wind Technology Undiminished by US Political Climate

NATIONAL HARBOR, Md. — Despite the political headwinds currently buffeting the offshore wind sector as a whole in the United States, work continues on how to foster the industry’s success over the long term.

One example of that was the floating wind turbine platform developed at the University of Maine and on display at the ARPA-E Energy Innovation Summit held this past week at the Gaylord National Resort and Convention Center.

While floating turbine systems are nothing new — in fact, there were several booths at the summit devoted to them — what made the platform designed by the University of Maine’s Advanced Structures and Composites Center different was that it was made almost entirely from concrete.

Mike Olsen, the center’s commercial manager for floating offshore wind, explained how it works.

“Typically when we think of offshore wind, we think of turbines being stuck directly into a seabed, right?” Olsen said.

“The problem is in a location like this,” he continued, turning toward a map at the back of his booth and pointing to the Gulf of Maine.

“Here, the seabed just drops right off. So it’s just not feasible to stick your turbine there,” Olsen said.

“The other thing,” he said while running a finger across the irregular outline of the Maine coast, “is that your wind is obstructed by all this … stuff … the terrain west of your location.

“So you benefit by moving further away from the coastline, where the wind is not only stronger but steadier,” he said. “But the problem is, you can’t anchor anything into the seabed out here because it’s simply too deep.”

At the University of Maine, a team for 50 researchers developed their now patented VolturnUS floating platform technology.

The first order of business was creating a platform that was strong enough to emulate the sea floor without making it so large that it would become prohibitively expensive.

Next it had to be stable. To solve this problem the research team decided to fill hollows in the cement structure with sea water, which would then act as ballast.

“It acts kind of like the mass dampers on a skyscraper,” Olsen said. “The wind spins the turbine, waves hit the platform. Yet the whole thing remains stable because of the seawater moving inside.

“If this thing wobbles, it’ll break. It’ll shorten its life. So the whole idea is to design it with an eye toward it being there for 25 years or more,” he said.

But why cement? 

Olsen explained that in many instances, local governments provide extra incentives to project developers who use local labor and materials.

“Everybody’s got the ability to make concrete locally, right? Steel, on the other hand, mostly comes from China, so in addition to supply chain and other issues, you’ve also got a bigger carbon footprint,” he said.

“Besides, concrete is less affected by the salt water than steel; it simply ages better,” he said, adding, “that helps make these platforms reusable. … So, after 25 years, you just take the aged turbine tower off and replace it.”

The researchers are now working with DeepCWind, an entity formed expressly to provide design support and help the university commercialize its offshore wind technology.

Together the two are developing the Maine Research Array, a project that will consist of 10 15-MW turbines located in a 15.2-square-mile box more than 20 miles offshore. The Bureau of Ocean Energy Management awarded the project a research lease last year.

Asked how the change of the political climate has affected the project, Olsen returned to the map, which showed clusters of orange dots off the coast of Maine, the Pacific Northwest, Great Britain and Japan.

“Obviously, the current climate doesn’t affect any of this,” he said, pointing to the waters off Maine. “The leases are all done and this is all going gangbusters. The research array is very far along.

“And we’ve got two here in the North Sea that are very far along in the final engineering study phases. So we’re doing pretty well outside the United States, and even okay here,” he said.

“Let me show you something that will give you more of a sense of scale,” he continued, pointing to yet another chart, this one color coded.

“Now, the blue here, that represents the U.S. market as we saw it prior to the election. Now, we may have to move our timeline and expectations a little further out here, but the rest of it,” he said, the sweep of his hand taking in the rest of the developed world, “is moving along just fine.”

Dan can be reached at [email protected] and @DanMcCue