Research looks at using wind to weaken hurricanes

Turbines at a wind farm in the North Sea off Germany. Using turbines would be "almost like bringing back the old coastal forests and putting them out to sea to interrupt the storm," one scientist says.
Turbines at a wind farm in the North Sea off Germany. Using turbines would be "almost like bringing back the old coastal forests and putting them out to sea to interrupt the storm," one scientist says. (Getty Images)
Posted: March 05, 2014

Wind turbines have been lauded as carbon-free energy sources, and denounced as whirring monsters that kill birds, bats, and scenic views.

The twain have yet to meet.

But what if wind energy could do more than just crank out electricity? What if it could blow away Mother Nature with a massive offshore array of turbines powerful enough to blunt the force of hurricanes?

Researchers from the University of Delaware and Stanford University have concluded it is possible.

Their computer model showed that a large wind farm off the East Coast could have have reduced the wind speed of Hurricane Sandy about 80 m.p.h., and lessened the storm surge - the flooding that ruined so many homes and businesses - up to 21 percent.

How large a wind farm is the catch. To protect the corridor between Washington and New York, the researchers calculated, more than 100,000 turbines would be required.

That number strains the most unrestrained imagination, given that the largest offshore wind farms now being planned call for 150 to 200 turbines. The one closest to completion in this region, a Fishermen's Energy project, would put just five turbines in state waters 2.8 miles off Atlantic City. Proposed in 2008, it still awaits final approval.

University of Delaware associate professor Cristina Archer, one of the authors of a paper in the March issue of Nature Climate Change, concedes that the concept falls squarely into the realm of the theoretical.

It's tantalizing, nonetheless, others say.

"I think it could work," said Mark Powell, an atmospheric scientist for the National Oceanic and Atmospheric Association's Hurricane Research Division in Miami. "It's almost like bringing back the old coastal forests and putting them out to sea to interrupt the storm."

Stephen Rose, a Carnegie-Mellon University post-doctoral researcher, has analyzed the flip side - potential risk to turbines from hurricanes - and also is intrigued.

"I'm an engineer by training, and we're optimistic about these things, so I'm going to say it's possible to build that many wind turbines," he said, "although it would be a lot of work."

Public acceptance could be more problematic than the technology. "It's taken them 10 years to accept 130 turbines off the coast of Massachusetts," Rose said.

Far fewer than 100,000 turbines could still have a big effect, Archer suggests. She and her co-authors - Delaware's Willett Kempton and Stanford's Marc Jacobson - have yet to run smaller turbine arrays through their computer model.

The model results for a 100,000-turbine project stunned them. "We were expecting that winds would be a little weaker downwind of the farms, but they were significantly weaker," Archer said. "We certainly didn't expect to alter the structure of the storm. But we did."

The underlying principle is simple. It takes energy to rotate an object, and in this case, the blade - an arm often 150 feet long, extending from a hub height of 300 feet - absorbs the energy from the wind. "The wind cannot simply hit the turbine, make it spin, and continue as if nothing happened," Archer said.

Regardless of its impracticality, the research has "given some interesting insight into how storms might interrelate with turbines," said Nancy Targett, dean of Delaware's College of Earth, Ocean and Environment, where Archer is on staff. "It might lead to things with more specific and real impacts."

What if, instead of spending billions to build sea walls, we put the money into offshore wind farms?

What if, instead of designing the turbines for maximum output in light winds and shutting them down during storms, we built them with storm abatement in mind?

What if we included factors such as hurricane damage avoidance into the overall financial calculations of the wind farms? Archer and her coauthors did, concluding that damage avoidance, reduced air pollution, health advantages, and climate benefits could make the per-kilowatt-hour cost of wind about half that of new fossil-fuel generation.

Archer also has also looked at how best to arrange turbines: Instead of perfectly aligned rows and columns, they should be staggered.

Kempton has studied how a huge, spine-like electrical cable linking a series of coastal wind farms could lessen the variability inherent in wind power, making it more workable for the grid. (A $5 billion project to build one was proposed in 2010.)

The University of Delaware is emerging as a powerhouse of wind energy research.

A research turbine erected at its Lewes campus has been churning out data since 2010. And last week at a Boston conference, the university announced a "Special Initiative on Offshore Wind" that would serve as a nexus of research, policy analysis, and information on financing.


BY THE NUMBERS

100,000

Estimated number of turbines needed to protect the corridor between New York and Washington from hurricanes.

80

Miles per hour the turbines could have slowed Hurricane Sandy, lessening the storm surge

by 21 percent.

5

Number of turbines proposed for the Fishermen's Energy project, 2.8 miles off Atlantic City.


sbauers@phillynews.com

215-854-5147 @sbauers

www.inquirer.com/greenspace

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