Wind Farms as Hurricane Busters!

Did you know that offshore wind farms can take some of the stings out of hurricanes? In a study by Stanford University published this week, it appears that large offshore wind farms can cut the wind speed of hurricanes by as much as nearly 100 mph and lower storm surge by nearly 80%.

Obviously, a hurricane blowing through a wind farm wouldn’t lose all of its force, but the study indicates that much of the initial force could be blunted before the winds hit the coast and move inland. Much less damage would occur to onshore structures. But wouldn’t the offshore turbines themselves be damaged? No. Modern wind turbines can withstand winds of over 110 mph.  How many turbines would you need in an offshore wind farm in order to dissipate the force of the hurricane? Ah. There’s the catch… You’d need a massive wind farm comprising tens of thousands of turbines. That’s a wind farm on a scale we’ve never seen before. The biggest offshore wind farm planned at the moment is Cape Wind off the Massachusetts coast in the United States. That will have 130 turbines.

But in theory, there’s nothing to stop building an offshore wind farm of ten thousand turbines. Not only would such a mega-farm supply many households with renewable energy, but it would also protect the coastal communities from the worst effects of a hurricane.

The study was undertaken by Mark Jacobson, a professor of civil and environmental engineering at Stanford University.

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“The primary purpose would be power generation — that’s how it pays for itself,” said Jacobson, who conducted the study along with Cristina Archer and Willett Kempton from the University of Delaware. “Plus, in theory, you’ve just saved yourself a lot of money by not putting up so many seawalls.”

Jacobson is a well-known character to US audiences- he has appeared on television’s The Late Show with David Letterman. He has considerable experience in building computer models to simulate atmospheric behaviour and then using the models to study pollution and global warming. He is passionate about renewable energy and argues tirelessly for more offshore wind farms to be constructed. For the study, Jacobson and his colleagues used simulations of three recent hurricanes: Sandy and Isaac from 2012 and Katrina in 2006.

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The theory is quite simple-as air flows through a wind turbine — onshore or off — it loses some of its speed, creating a wake of diminished wind nearby. Jacobson’s modelling found that large numbers of wind turbines could cut the airspeed and therefore the wave heights, at the outer edge of a hurricane. That, in turn, would reduce the amount of energy flowing to the centre of the storm.

An array of 78,000 wind turbines off the U.S. Gulf Coast, the researchers found, could have slashed Katrina’s wind speed between 80 and 98 miles per hour by the time the storm hit New Orleans. Storm surge would have dropped as much as 79 per cent.

With Hurricane Sandy, which swamped the coast of New Jersey and knocked out power to lower Manhattan for days, the models found a wind speed drop of 78 and 87 miles per hour and a 34 percent cut in the storm surge.