It might be stating the obvious, but scientists writing in Nature Climate Change note that if we grabbed all the wind power available on Earth and turned it into electricity, there would be “pronounced climatic consequences.”

Fortunately, according to the researchers, there is vastly more wind energy available in our atmosphere – as much as 1,873 terawatts, they say — than the current primary power demand of 18 TW. That means that “uniformly distributed wind turbines are unlikely to substantially affect the Earth’s climate” even as the turbines give us every last electron of energy we need.

altaeros energies high altitude wind turbine
image via Altaeros Energies

So have we cracked the climate conundrum? Wind power is our savior?

Not really.

The study’s authors, from the government’s Lawrence Livermore National Lab and the Cargnegie Institution Department of Global Ecology, note they don’t address the economic, political and technical constraints of wind power. So this isn’t a proposal to blanket the planet with turbines. Instead, it’s an exploration of the “geophysical limits to wind power” – how much energy can be extracted before drag renders the atmosphere motionless – and what the large-scale climate impacts would if we moved toward that limit.

The good news: At what was termed “civilization scale reliance on wind power,” uniformly distributed turbines near the Earth’s surface would lead to just a small surface warming effect, the researchers said, while whole-atmosphere extraction would have a similarly minor cooling effect. In both cases global average precipitation would decrease by around 1 percent.

The study authors — Kate Marvel, Ben Kravitz and Ken Caldeira — found that using only turbines at the surface, the limit on wind power availability is 428 TW. In the entire atmosphere – this presumes using high-altitude airborne turbines – 1,873 TW is available.

This big number explains why scientists, analysts, dreamers and schemers have for years mused upon mining Earth’s high speed winds that are out of reach of turbines on even very tall poles.

Some are looking to go just 1,000 feet up, like the Altaeros project out of Massachusetts, which has tested a prototype at 350 feet altitude. The company believes it can trim the cost of wind power by 65 percent by accessing high-altitude winds that it says blow steadier and fives times stronger than the winds that today’s tower-mounted turbines rely on.

Others are looking even farther skyward. The consultancy GL Garrad Hassan said in a 2011 report that 22 companies have developed or announced they plant to develop prototypes – kites, kytoons, aerostats, gliders, sailplanes … you name it – that could harness wind resources more than 1.2 miles about Earth’s surface.

This new study could feed these perhaps grandiose hopes, and it’s not the only word on the subject. The Marvel/Kravitz/Caldeira conclusion that there is a vast resource of wind power available — both at the surface and much higher — fits pretty well with recent research by Stanford’s Mark Jacobson. His whole-globe total is a bit less robust than the other team’s, but he still found “no fundamental barrier to obtaining half or several times the world’s all-purpose power from wind in a 2030 clean-energy economy.”

In an interview with U.S. News & World Report, Jacobson’s co-author, Christine Archer, said 4 million land-based turbines would do the trick. The difficulty in pulling this off — just imagine the land-use conflicts — is a big part of the reason some think we should like higher into the sky. And yet there are skeptics on the science of high-altitude wind: Late last year, German researchers published a piece in the journal Earth System Dynamics title, “Jet stream wind power as a renewable energy resource: little power, big impacts.”

These researchers said that one of the factors that allows the air to move so quickly and consistently at altitudes between four and 10 miles also explains why high-altitude winds could have scant wind-power value: There’s very little friction at those altitudes, the researchers said. That means it takes only small amounts of energy to drive the winds, which in turns means there’s actually very little power available for turbines to grab.

skywind
image via Sky Wind Power

The team out of the Independent Max Planck Research Group on Biospheric Theory and Modeling concluded that the wind possibility up in the atmosphere was just 7.5 TW, and their kicker was extracting all that energy “would have a drastic impact on temperature and weather.”

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