The deepwater solution

By Craig Salters
The Cape Codder

Can the United States, the first nation to put a man on the moon, develop deepwater wind turbines capable of harnessing the ocean's vast wind resources?
The answer is "yes." Unfortunately, it's not the right question, because the real puzzler is whether deepwater technology can be made cost-effective. If it can - and experts believe the answer to that question may be at least a decade away - deepwater wind farms could offer a real alternative to fossil fuels or nuclear energy.
Deepwater wind farms could also provide an alternative to their near-shore cousins, proposed projects such as Cape Wind's bid to build a wind farm in Nantucket Sound. Such projects have sparked controversy for a number of reasons, not the least of which is that, however large or small, they can be seen from the shoreline.
Then again, argue some, we may have to build near to get far.
"Mostly, in terms of technology, we could do it (build in deepwater) today, but would a business want to invest in it?" asked Walt Musial, senior engineer at the National Wind Technology Center, part of the National Renewable Energy Laboratory. The laboratory, in turn, is part of the Department of Energy's national lab system along with more famous sites such as Argonne, Brookhaven and Sandia.
Musial, who is in charge of offshore wind programs, said approximately 60 researchers work on various "parts of the puzzle" when it comes to wind power in general. Regarding offshore wind, he said, the center didn't even approach the problem until a few years ago.
"As a lab, we're just getting into this research," he said.
According to Musial, the center does not view offshore wind as land turbines "with some marinization" and is not focused on one or two offshore proposals. Its current goal, he said, is to see what breakthroughs would be necessary for the United States to enter offshore wind in a serious way.
"We're talking about new technologies that would need to be developed," he said. "It's an 'R and D' [research and development] question."
Right now, Musial said, the technical limit for offshore wind farms is about 25 meters deep. After that, problems occur, such as turbine foundations becoming more costly to ship and install in the ocean floor. Another problem is the monopoles themselves, which become unwieldy with increased height, weight and diameter. Maintenance also becomes more of an issue due to severe ocean storms.
Then there's transmission costs, with a project's price tag rising by about $1 million for every additional mile of cable.
"Basically, it's the substructure that gets more expensive," he said.
Developing more powerful turbines, machines which could double the output of today's 3.6 megawatt models, would reduce costs because they would reduce the number of foundations needed for the same amount of energy. Put another way, it costs the same to lay one transmission cable but it's a lot cheaper if that cable connects to 40 turbines and not 80, provided the energy output is the same.
"A big part of the game is to get more energy from the same area of swept blade," Musial said.
Scotland's project
One of the more ambitious deepwater projects is to be found 15 miles off the coast of Scotland where Talisman Energy is installing a pair of 5 megawatt turbines in water 45 meters deep. At a cost of more than $60 million, the turbines will provide power to nearby gas and oil platforms.
"They're doing what needs to be done," Musial said of what Talisman calls a demonstrator project. "The first project that goes in is never going to be cost effective."
Musial added that Cape Wind's plan and a similar project proposed for Long Island are not demonstrator projects but are based on models already working in Europe. While not offering comment on the merits of either project, he credited the proposals with pushing the envelope in terms of federal regulation and review of offshore wind farms.
Some of the "next step" technology under consideration for deepwater turbines includes tension leg platforms, which use several vertical legs instead of one monopole. There's also the idea of a floating platform, which are then tethered to the ocean floor.
In reality, much of that technology already exists in the oil and gas industry - "There are floating platforms in the Gulf of Mexico right now," Musial said - but oil rigs and wind farms are not one and the same.
"For oil rigs, every one of them is a custom job," said Musial, who explained that, unlike oil and gas rigs, deepwater wind farms would require some form of mass production.
Solution for the century?
The payoff for all the research and development lies in the fact that, according to Department of Energy estimates, the U.S. possesses around 900,000 megawatts of potential offshore wind power, or about the nation's current electrical capacity. Furthermore, almost 80 percent of that untapped energy is found in waters more than 20 miles offshore.
While states such as North Dakota and South Dakota are known as "the Saudi Arabia of wind," Musial said that, since they aren't near major population centers, transmitting the electricity to cities and suburbs is cost prohibitive. Not so with offshore wind power, which is adjacent to coastal cities.
"It's not just a few projects," said Musial. "[Deepwater wind farms] could contribute to the energy solution for this country."
For Greg Watson, vice president for sustainable development and renewable energy for the Massachusetts Technology Collaborative, the deepwater question is both a challenge and an opportunity.
"Massachusetts is poised to be a leader in this field," said Watson. In fact, he said, researchers from MIT and other universities are already hard at work on the details of such things as floating platforms for turbines. "It promises real, honest-to-goodness manufacturing jobs."
Watson said that, whether it be off Hull, Cape Cod, Long Island or somewhere else, the nation would need practical experience in near-shore wind farms before it literally ventured into deeper waters. The deepwater solution, if there is one, is still in the future.
"We could be talking 10 to 15 years but it all depends on the resources we put into it," said Watson, referring to the need for "an Apollo mentality" from the nation and its leaders. "If we got serious, we could cut into that timeframe."
To that end, MTC has partnered with GE and the DOE to form the Offshore Wind Collaborative, an organization that seeks to bring the best and brightest together on the topic of offshore wind. In September 2005, the collaborative released "A Framework for Offshore Wind Energy Development in the United States," a 30-page document which identifies the steps needed to develop this untapped resource.
"It's a road map," said Watson. "We're bringing people together who've never talked to one another before [about offshore wind]."
Within the next month, the collaborative will introduce a business plan to achieve the goals set out in the framework. Again, the idea is to bring the concept of deepwater wind farms that much closer to reality.
"The question is how can we do it economically," said Watson. "Can we go beyond the horizon?"

August 25, 2006