Large offshore wind turbine arrays may help protect vulnerable coastal areas from the worst impacts of landfalling hurricanes, according to a new study, in addition to producing renewable energy.

The research, published on Wednesday in the journal Nature Climate Change, found that large turbine arrays producing at least 300 gigawatts of electricity — far more than any offshore wind project in service today worldwide — can significantly reduce a hurricane’s maximum surface winds as well as its deadly storm surge.

The study, from researchers at Stanford University and the University of Delaware, showed that if a large offshore wind turbine array had been in place off the southeast coast of New Orleans when Hurricane Katrina came ashore in 2005, it would have slashed the storm’s wind speeds by up to 79 mph at 15 feet above the surface in a region downwind from the turbines. It also would have reduced the maximum storm surge by up to 80%.

The wind speed and storm surge reduction benefits would depend on the exact locations of the turbines relative to the storm’s path, according to the study.

It comes in an era of increasing damage costs from hurricanes due to increased coastal development and sea level rise related to manmade global warming. Hurricane Sandy alone caused at least $80 billion in damage, the study found, much of it from the storm’s record high wall of water that swept across the New Jersey shore as well as parts of New York City.

The study, which used a sophisticated computer model that can estimate the 3D interactions among hurricanes, the ocean surface and wind turbines reaching up to 330 feet in height, found that hurricanes would transfer some of their kinetic energy to the turbines beginning when the outer areas of strong winds reached them. This would set off a chain reaction involving the forces that help strengthen or weaken a storm, resulting in a temporarily weaker hurricane.

“The hurricanes themselves were weakened, their winds were weaker, their pressure was higher with turbines than without,” Cristina Archer, a co-author of the study, told Mashable.

Reduced wind speeds, for example, would lower the wave heights, and smaller waves would lower the force of friction at the surface. This would slightly alter the path of the air rushing toward the center of the storm; instead of moving inward toward the eye, air would move around it, raising the central air pressure at the storm’s core. In general, the lower the pressure, the stronger the storm, so a higher air pressure means the storm would be less intense.

Hurricane Sandy, for example, set a record for the lowest air pressure reading on record north of Cape Hatteras, N.C. But according to the study, if Sandy had passed over a massive offshore wind installation before making landfall, its minimum central air pressure would have risen, its storm surge would have lessened, and its winds would have decreased in intensity.

Specifically, computer model simulations showed that the turbine arrays reduced Sandy’s maximum storm surge by up to 34%, and Sandy’s winds by up to 87 mph at a height of 15 feet. The entire storm would not have been far weaker, but at least the area downwind of the turbines would have experienced less severe winds and waves, the study found.

Life cycle of Hurricane Sandy: Surface Wind Speeds. Credit: UCAR.

Perhaps the biggest criticism of the study is that no energy company is currently seriously contemplating building offshore wind turbine arrays nearly as large as the ones used in the research, said Mark Jacobson, an engineering professor at Stanford and co-author of the study. In fact, efforts to build offshore wind turbines have been met with regulatory hurdles and local "not in my backyard" opposition. The 300 gigawatt arrays would involve up to 400,000 turbines. For comparison, the Cape Wind project, which is under construction off of Cape Cod, Mass., will only involve 130 turbines.

“That is really a social, economic, and political question,” Jacobson told Mashable.

There are also questions regarding whether turbines can withstand the onslaught of a high-end hurricane like Katrina. Some experts maintain they would be the first infrastructure to get destroyed by a storm. According to the study, though, the turbines would reduce the winds enough that most would survive.

Not a weather modification scheme

Archer and Jacobson, the co-authors, were careful to distinguish between using wind turbines for energy, with the side benefit of storm reduction, and past attempts at altering storms to protect coastlines.

The U.S. has a long history of trying to alter the power of storms, particularly hurricanes. The federal government, for example, pursued a program known as Project Stormfury between 1962 and 1983, which unsuccessfully sought to use cloud seeding techniques, which involved flying into storms to spray them with silver iodide, to reduce hurricane intensity. More recently, some have proposed using ocean pumps to pull warm water from the surface of the sea, which hurricanes feed from, and replace it with cooler water from deeper ocean depths.

Jacobson said the wind turbine approach is far simpler than weather modification ideas. “This doesn’t require going out and trying to spread something over the entire hurricane, it just requires the turbines to be in a specific location near a city," he said.

Archer and Jacobson added that they are not advocating for another weather modification scheme, but rather proving yet another reason why pursuing offshore wind energy would be beneficial. “It’s not like we’re trying to weaken the hurricane, we get that as a secondary benefit,” Archer said.

According to the study, once hurricane-related benefits are taken into account, offshore wind energy installations would be even cheaper compared to land-based fossil fuel plants. In addition, they would have far more benefits than building new storm surge barriers, such as sea walls, which don’t generate electricity on the side. A potential sea wall constructed to protect much of New York City against another Sandy-magnitude surge could cost up to $29 billion, according to the study.

While the greatest reductions in storm strength were associated with the largest turbine arrays, Archer said smaller installations also had measurable effects on simulated hurricanes. “We still saw benefits in terms of wind field reduction and storm surge reductions,” she said. “I think this is absolutely an option to protect coastal communities.”