Offshore wind farms can protect against hurricanes

New research suggests offshore wind turbines can absorb significant energy from hurricanes, reducing winds, waves, and storm surge. A bank of wind turbines strategically placed off the coast could have reduced hurricane Sandy flooding by up to a third and the winds of Katrina by up to 92 miles per hour.

Robert F. Bukaty/AP/File
A floating wind turbine works off the coast of Castine, Maine. New research suggests that offshore wind farms can absorb large amounts of energy from hurricane winds, before they hit shore.

Hurricane Sandy may have darkened and damaged parts of the East Coast when it blew ashore in the fall of 2012. But it also forced the region to enter its era of enlightenment – to come up with new ideas on how to beat back Mother Nature.

The latest big idea: wind turbines. New research from the University of Delaware and Stanford University suggest that offshore wind farms remove energy from a storm’s edge and slow down fast-moving winds. Thus, they would reduce hurricane wind speeds, wave heights, and storm surge that leads to flooding.

In the case of hurricane Sandy, strategically placed wind turbines would have reduced flooding by up to 34 percent. Windmills in the Gulf of Mexico would have reduced hurricane Katrina flooding by up to 79 percent. They would also have a dramatic effect on reducing wind speeds, beginning at the outer reaches of both hurricanes – reducing hurricane winds by up to 87 m.p.h. and 92 m.p.h., respectively.

The turbines would not be enough to knock down the highest winds around the eye wall of a Category 2 hurricane, for example, to make it a Category 1, says Cristina Archer, a co-author of the report and professor at the University of Delaware, in an interview. But the lower wind speeds at the hurricane’s perimeter would gradually filter inwards and to the storm eye, mitigating the overall damage. “The turbines do more than a wall, because they take up the energy” of the wind.  

“This is a paradigm shift,” said Willett Kempton, another co-author and professor at the University of Delaware’s College of Earth, Ocean, and Environment, in a release. “We always think about hurricanes and wind turbines as incompatible. But we find that in large arrays, wind turbines have some ability to protect both themselves and coastal communities, from the strongest winds.”

Beyond the prevention of significant damage to cities – think New Orleans, 2005 – the offshore wind turbines would also serve to produce cleaner year-round electricity, say the authors. That makes the technology an alternative to constructing seawalls, say Professors Archer and Kempton and Mark Jacobson (Stanford University), whose findings were published Wednesday in the journal Nature Climate Change. 

The authors conclude that the net cost of offshore wind farms are less than the cost of generating electricity from fossil fuels. The variables that they take into account are the net savings from avoided health-care, climate change, and city damages as well as avoided infrastructure costs tied to seawalls.

To be sure, skeptics could poke several holes in the researchers’ assumptions. Even if wind turbines do slow down hurricane winds, what are the odds that coastal communities will allow wind farms to proliferate off the Atlantic and Gulf coastlines? If they did sprout up, would they actually be as cost efficient as the authors say?

The US Department of Energy would like to have 54,000 megawatts of offshore wind by 2030. Those scenarios include development in both federal and state offshore areas, including along Atlantic, Pacific, and Gulf coasts as well as in Great Lakes and Hawaiian waters, the agency says.

While the regulatory headwinds stymieing offshore wind production are easing, the bigger obstacles are financial and technical.

Consider Cape Wind, the high-profile offshore project planned for the Massachusetts coast that has languished for about a decade. Although it has survived multiple regulatory hurdles, it must still overcome some legal challenges.

Then there’s the Atlantic Wind Connection, which was initially conceived to be the undersea backbone spanning 380 miles from New Jersey to Virginia. The collaboration, which involves Google, is getting scaled back to focus on New Jersey. Just creating the New Jersey link would cost an estimated $1.8 billion. Objectively speaking, there are less expensive and more immediate ways to feed the state’s electricity demand, namely combined-cycle natural gas plants.

It’s not just traditional generation that has the edge. Land-based wind facilities cost 50 percent less to build than offshore wind units.

Also, NRG Energy has indefinitely delayed its wind deal off the Delaware coast until it can find dependable investment partners. Spanish wind developer Gamesa has suspended its plans to build off the Virginia coastline, citing the need for financing at a time of political uncertainty.

“The odds of any offshore wind facility going forward are not good unless we have a federal policy that mandates carbon reductions,” says Peter Asmus, principal research analyst for Navigant in San Francisco, in an interview. “That is what is driving wind development in Europe, which has nowhere else to go but offshore.”

The University of Delaware and Standard University researchers can vouch for their findings, but they cannot directly influence public policy decisions or entice the capital markets to finance offshore wind projects. While their discoveries may hold up in the lab, they are unlikely to withstand an even fiercer storm – the volatile political and financial winds that are keeping offshore wind from going forward.

[Editor's note: This piece has been updated with the correct spelling of Willett Kempton.]

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