The benefits of offshore wind farms might see obvious: cheap, abundant, clean energy.
But preventing billions of dollars in damage? That's right, there's another benefit that has nothing to do with energy. Huge offshore wind farms could play a role in stifling the impact of hurricanes.
A new study published in the journal Nature Climate Change [pdf], out of Stanford University, built a computer model that simulated what would happen if a hurricane -- like Katrina, Isaac, or Sandy -- collided with a large offshore wind farm with thousands of wind turbines stretching for miles along a coastline. The results, according to Mark Jacobson, a professor at Stanford University:
"We found that when wind turbines are present, they slow down the outer rotation winds of a hurricane," Jacobson said. "This feeds back to decrease wave height, which reduces movement of air toward the center of the hurricane, increasing the central pressure, which in turn slows the winds of the entire hurricane and dissipates it faster."
To be clear, to have this big of an impact, there would need to be thousands of wind turbines. The model with the fewest number of wind turbines -- more than 78,000 off the coast of New Orleans -- shows that the wind farm could have slowed Hurricane Katrina's peak wind speeds by as much as 80 miles per hour and reduce the storm surge's impact on New Orleans by a wide ranging 6-71 percent.
On the other hand, if there were an almost unbelievable 543,000-plus wind turbines placed along much of the Gulf Coast it could have reduced peak wind speeds during Hurricane Katrina by more than 90 miles per hour and reduced the storm surge along the coast by 26-75 percent.
While the impact of reducing offshore wind on hurricanes seems clear, what's not clear is whether offshore wind farms will ever be large enough, as in the simulation, to have any impact on hurricanes. The largest offshore wind farm in the world, currently, has just 175 wind turbines. In the United States, states are struggling to build offshore wind farms with less than 100 turbines. There are currently no offshore wind farms operating or under construction in the U.S. even though the potential generating capacity is huge.
Still, Jacobson and his colleagues make a strong economic case for investing in these massive wind farms along coastlines that are regularly threatened by hurricanes, even more so than other hurricane solutions like costly seawalls. As the study explains:
Turbines pay for themselves from the sale of electricity they produce and other non-market benefits (Table 2), but sea walls have no other function than to reduce storm surge (they do not even reduce damaging hurricane wind speeds), so society bears their full cost. Conversely, if wind turbines are used only for hurricane damage avoidance, an array covering 32 km of linear coastline in front of New York City would cost ~$210 billion with no payback ..., higher than the cost of proposed sea walls, $10-29 billion. Thus, turbines cost much less than sea walls to protect a city, as turbines also generate electricity year-round, but if turbines were used only for hurricane protection, sea walls would be less expensive.
With Hurricane Sandy alone costing an estimated $82 billion in damages, a $200 billion-plus wind farm that can produce a huge amount of energy and reduce the huge cost of future hurricanes, starts to sound like a pretty good deal.
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