Ocean Wind Turbines Could Power the World…But Cool the Arctic by 13°C
A corridor of wind turbines across the North Atlantic could theoretically deliver enough “civilization-scale power” to fully meet the world’s electricity demand, according to a Carnegie Institute for Science study published in the Proceedings of the National Academy of Sciences.
An expanse of three million square kilometres, larger than the area of Greenland, would deliver the 18 terawatts of electricity that humanity currently consumes, the Washington Post reports. “On an annual mean basis, the wind power available in the North Atlantic could be sufficient to power the world,” the study states.
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“I would look at this as kind of a greenlight for that industry from a geophysical point of view,” said Carnegie’s Ken Caldeira, who collaborated with lead author Anna Possner.
But the Post stresses the “purely theoretical calculations” in the study “are thwarted by many practical factors,” including seasonal variations in wind speeds, an Arctic cooling effect of up to 13°C, and the fact that the technology to extract that much ocean wind doesn’t exist.
“It’s very unlikely that we would ever build out open ocean turbines on anything like that scale,” the paper notes. “But the more modest message is that wind energy over the open oceans has large potential—reinforcing the idea that floating wind farms, over very deep waters, could be the next major step for wind energy technology.”
That observation matters because of the inherent limits on the electricity an onshore wind farm can generate, explains Post climate specialist Chris Mooney. The constraints begin with friction from natural and human structures—including nearby wind turbines—that reduce wind velocity. “If each turbine removes something like half the energy flowing through it, by the time you get to the second row, you’ve only got a quarter of the energy, and so on,” Caldeira said.
Over the oceans, “wind speeds can be as much as 70% higher than on land,” Mooney writes. “But a bigger deal is what you might call wind replenishment. The new research found that over the mid-latitude oceans, storms regularly transfer powerful wind energy down to the surface from higher altitudes, meaning that the upper limit for how much energy you can capture with turbines is considerably higher.”