Will Hurricane Isaac Destroy Wind Turbines?

Guest Blog | August 24, 2012 | Energy Policy, Wind

Here in the Southeast, hurricanes are no strangers to our coastlines. Just 20 years ago this year, Hurricane Andrew hit Florida with devastating force. Despite the risks posed by hurricanes, many people feel like the benefits of living in warm subtropical areas is worth the risk of losing it all in a huge hurricane. Businesses are no different.

But for some reason, one industry has drawn exceptional media coverage over its interest in the Southeast: the wind industry. Just about anytime someone mentions a wind farm development in Florida, or off the coast of North Carolina or Texas, one of the first questions posed is, “What about hurricanes?” With Hurricane Isaac looking to bear down on Florida, now seems like a good time to answer the question.

No, Hurricane Isaac will not destroy wind turbines. First, there aren’t any wind farms built in Florida (yet). Even if there were, wind turbines specifically designed to withstand hurricanes are commercially available. Based on the current projections, the first wind farm for Hurricane Isaac to encounter may be the Buffalo Mountain wind farm in Tennessee – about 400 miles due north from the Gulf of Mexico. If Isaac does make it that far inland, it’ll likely just be a windy rain storm. (For an actual hurricane strike on wind farms, check our our previous blog series on Hurricane Irene from last year).

But what about future wind farms? How will hurricanes impact those installations?

Wind turbines are readily designed to withstand extreme winds – even up to Category 3 hurricanes. But last year, a study released in the Proceedings of the National Academies of Science by some Carnegie Mellon researchers estimated that half of offshore wind turbines would be destroyed by hurricanes off the coast of Texas.

Unfortunately, both the media and the researchers got the information wrong. We highlighted some of the problems of the study in a previous blog post, but it has now come to light that the researchers severely overstated the risk of hurricanes to wind farms.

Dr. Mark Powell, an atmospheric scientist for the National Oceanic and Atmospheric Administration’s Hurricane Research Division in Florida, submitted a letter to the National Academies of Science critiquing the Carnegie Mellon paper. Dr. Powell found that the Carnegie Mellon paper overestimated the risk to wind farms from hurricanes by more than an order of magnitude.

On the Hurricane Research Division’s blog, Dr. Powell wrote:

“An error and several poor assumptions in the original approach were found. In a new analysis of the same hypothetical wind farm, we found an average loss of 2 turbines per 20-year period, compared to 24 using their methods. In their response to the letter, the revised approach downgrades the risk from a 41% to a 2% chance of losing 10 or more turbines over a 20-year period. This is over an order of magnitude downgrade in the risk, but still relies on a flawed approach using fits to statistical extreme value distributions. We recommend the use of industry-standard risk models similar to those used to estimate risk in the residential insurance market in Florida.”

The Carnegie Mellon researchers conceded in a response to Dr. Powell that they overestimated the risk.  It’s important to note here that both the original study and the correction still presume that the wind turbine’s already built-in survival mechanisms, like active yawing (which turns the turbine into the wind), were turned off, potentially making these figures overestimates and unrealistic.

Unfortunately, chances are that Dr. Powell’s research is unlikely to receive as much fanfare as the original publication, which is a real shame. The hurricane risks have been overstated for offshore wind farms, especially here in the Southeast. If this myth continues to be perpetuated, it’ll be even more difficult for our region to move away from risky energy technologies and towards safer, sustainable energy choices. The question remains, if a hurricane were to destroy a power plant, which would you rather have — a pollution-free wind farm or an offshore oil rig, a coal, nuclear, or natural gas plant?

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