Wind turbines play a key role in tackling climate change, but now it seems they may also be able to mitigate hurricanes.
Wind speeds recorded downwind of wind farms are lower, as the spinning turbines have taken energy out of the passing wind. Scientists are looking at how this could affect storms.
Publishing in the journal Nature Climate Change, researchers based at the University of Delaware and at Stanford University, explain that if a large array of wind turbines were put in the right place, it could reduce hurricane wind speeds by up to 92 miles per hour and reduce storm surge, which is a key cause of flooding, by up to 79 per cent.
The team used information from previous hurricanes, including Katrina, which killed over 1800 people in 2005, and the more recent Sandy of 2012, which caused approximately US$82 billion of damage, to build a computer model of the storms.
They could then calculate what would have happened had there been an off-shore wind farm in the path of the storm.
In the case of a hurricane, the middle or ‘eye’ of the storm has the strongest wind speeds, about 50 metres per second (m/s), whereas in the outer edges of the hurricane the wind speeds are only about 20m/s.
As the storm comes in from the ocean, the outer edges are the first to hit the turbines. At these wind speeds, the turbines are still able to spin and convert the wind energy into electricity.
This reduces the wind speed, with the knock-on effect of de-powering the whole storm and cutting down the potential of the hurricane to do damage to coastal areas.
The researchers performed numerous simulations, varying the number of wind turbines in the farm, with hundreds of thousands to tens of thousands required to achieve the effect. But are wind farms of this size feasible?
According to study co-author Dr Cristina Archer, from the University of Delaware, “tens of thousands [of turbines] could be a realistic scenario, it would obviously take a long time and it would require commitment”.
Focusing on smaller scale wind farms, Archer points out that even “with one tenth of the turbines you would think you only get one tenth of the benefit but you don’t, you actually get more than sixty per cent of the benefit … with a smaller number of turbines than we used in the study, we are confident there are still benefits”.
Archer added “anything with a relatively large structure and has high winds would be impacted the same as the hurricane”. Therefore wind farms could provide storm protection for many more areas.
These farms would provide the most cost-effective storm protection to nearby coastal areas compared with other strategies, such as sea walls, as they may effectively pay for themselves through the electricity generated.
How wind farms tame hurricanes
Apparently the current large windmills do fairly well if they are furled, or put into "hurricane mode" prior to being struck by hurricanes.
A lot of friction could be generated if the brakes weren't applied properly, before the storm struck. If the blades moved only a little, that could generate a lot of power in the hub, perhaps producing the flames in the photo?
The paper's quite interesting (the reference is at the bottom of the article if you want to follow it up). You're right, the number of turbines needed is high - they simulate from 500,000 down to about 80,000. But, interesting, with 80,000 turbines, they still get 60% of the benefit returned by 500,000.
Seriously flawed economics and geophysics, I feel.
When looking at hurricane maps, many form either just west of Africa, or in the Caribbean sea.
Alan - the idea is to slow the incoming slowly-moving air that is feeding the storm. Conservation of angular momentum speeds this slowly-rotating air to become hurricane-force by the time it meets the eye-wall. The idea of the walls around the cities of the cost of mitigation against flooding, rather than wind... chris, Sat, 1st Mar 2014
What creates hurricanes? Tornadoes?
What about planting shrubs etc in the water, at the shores, binding the soil and creating a barrier, giving local fish wild life somewhere to dwell and hatch, as well as possibly also becoming a sort of buffer to storms? Think I read about Australian tries in that direction a little time ago? Can't find it now though. Otherwise I think I will agree with Alan. Seems a very costly and difficult solution, using the turbine construction we have today, with wings. Think I've seen some other solutions there, the wind entering a tunnel of sorts, maybe those would work better for strong winds? yor_on, Sun, 13th Apr 2014
I think there was a lot of talk about maintaining swampland in Louisiana for "storm surges". It doesn't do much for the wind, but it helps provide a buffer for waves from the sea. CliffordK, Sun, 13th Apr 2014