February 15, 2012
Offshore Wind Farms Vulnerable To Hurricanes
In a world of green energy aficionados, offshore wind farms have become all the rage. Yet with the U.S. poised to invest untold billions in the environmentally friendly power source, a recent study has caused many to question the financial liabilities associated with what now seems a very risky investment.
According to a study published Monday in the Proceedings of the National Academy of Sciences, yearly offshore hurricanes would likely destroy roughly half of the proposed wind turbines off American coasts.
With the U.S. Department of Energy´s plans to generate 20 percent of America´s electricity using wind by 2030, engineer Stephen Rose put together a crew or researchers to study the feasibility of the goal.
They focused on four locations in four states — Massachusetts, New Jersey, North Caroline and Texas — where the construction of major offshore wind farms are currently in the works. Using sophisticated computer-based simulations, the researchers found that over a period of 20 years, many of the expensive turbines would be demolished or rendered unusable.
Rose explained to Doyle Rice of USA TODAY that his team based their models on the current construction standards for wind turbines according to which most of the 20 planned projects would be built.
“Our study assumed wind turbine design for the current standards, with a maximum sustained wind speed of 111 mph near the top of the turbine, about [300 feet] above the surface. This is the equivalent of a Category 3 hurricane,” he told Rice.
Though engineered to withstand hurricane force winds, the researchers say that many of the electricity generating turbines would not withstand the repeated abuse from annual tropical storms.
“We find that hurricanes pose a significant risk to wind turbines off the U.S. Gulf and East coasts, even if they are designed to the most stringent current standard,” wrote the scientists at Carnegie Mellon University in Pittsburgh.
The planned Texas wind farm off the coast of Galveston County was the most vulnerable of the four locations they examined.
“As you get to Categories 3, 4, 5 – that´s where the risks are,” says Rose explained. “The intense hurricanes pose the most risk,” thus it´s no surprise that a site in Texas — which gets hit hard and frequently — would also be the riskiest.
The study pointed out that all the states bordering the Gulf of Mexico plus nine of the 14 states on the Atlantic Coast have been hit by a Category 3 or higher hurricane in the last 150 years.
And with an estimated price tag of roughly $175 million per wind farm, Rose´s colleague Paulina Jaramillo says investors need to know about the risks before they start building.
“We don´t want any backlash when the first one goes down and it costs a lot to replace,” she added.
But the study wasn´t all gloom and doom, and the researchers cautioned not to throw the baby out with bathwater. They noted that the potential for turbine destruction could be significantly lowered by simply constructing the wind farms in lower-risk areas and tweaking the design of the turbines to make them sturdier.
These two relatively simple measures, they wrote, could “greatly enhance the probability” effectively using offshore wind to meet the U.S.´s green-energy benchmarks.
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