Enough Energy In Wind to Meet World’s Demands

A detailed report was published last month in Nature Climate Change that concluded that there is enough energy available in winds to meet all of the world’s demand.  Carnegie’s Ken Caldeira examined the  limits of the amount of power that could be harvested from winds, adding in the effects that high-altitude wind power could have on the climate as a whole. His view is that atmospheric turbines  could generate even more power than ground- and ocean-based unit because they will be better able to harvest and convert the steadier and speedier high-altitude winds into energy

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Kate Marvel of Lawrence Livermore National Laboratory and her team used models to quantify the amount of power that could be generated from both surface and atmospheric winds. They defined surface winds as those that can be accessed by turbines supported by towers on land or in the sea. This is, of course the most common method of wind harvesting today.High-altitude winds were defined as those that can be accessed by technology merging turbines and kites. However the study looked only at the geophysical limitations of these techniques, not technical or economic factors. In other words- what was physically possible, if technology was available and economic and political considerations were put aside. But even given that, it’s a telling conclusion: Wind could power the world!

Turbines create drag, or resistance, which removes momentum from the winds and tends to slow them. Yes, you’d need an awful lof wind turbines to do that, but at at some point, the winds would be slowed so much that adding yet more turbines would not generate more electricity. This study focused on finding the point at which energy extraction from the wind would be the highest.

Using models and various formulae, the team were able to determine that more than 400 terawatts of power could be extracted from onshore and offshore winds and more than 1,800 terawatts could be generated by winds extracted from the atmosphere. A terawatt is 1 trillion watts, 10 to the power of 12.

At the present time, the world uses about 18 terawatts of power. Using the report’s calculations, surface wind could yield 20 times what we need at the moment, while atmospheric wind capture (using turbines on kites) could provide 100 times that amount.

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Today, civilization uses about 18 TW of power. Near-surface winds could provide more than 20 times today’s global power demand and wind turbines on kites could potentially capture 100 times the current global power demand.

What about climate effects to the wind harvesting with all these wind extraction devices all over the planet? The reports admits that if full and total global extraction was achieved, there would be substantial effects to the climate. However, if we used just sufficient wind for our world needs as they currently stand,  wind turbines might affect surface temperatures by about 0.1 degree Celsius and affect precipitation by about 1%. Overall, the environmental impacts would not be substantial. And of course what would the positive effects be with no need for fossil fuels?

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All rather exciting, but getting back to dull reality, Caldeira also says

“Looking at the big picture, it is more likely that economic, technological or political factors will determine the growth of wind power around the world, rather than geophysical limitations.”