Climate Change May Take Some of the Air Out of Wind Power

Climate Change May Take Some of the Air Out of Wind Power

Rising temperatures are projected to calm winds across the Northern Hemisphere’s middle latitudes, including the American Midwest, where wind energy accounts for a double-digit share of electricity generation in some states.

The push for clean power has seen a bumper crop of wind turbines sprouting from the Great Plains, but the future they’re trying to head off might leave many of them idled.

A warming climate is likely to calm some of the winds that now produce electricity across the Northern Hemisphere’s middle latitudes, while boosting breezes closer to the equator, according to new research by scientists at the University of Colorado. In the worst-case scenarios for warming, places where wind power is booming — the American Midwest, northern Europe or China — could see 10 percent less wind by mid-century and a decline of up to 18 percent by 2100.

Even in a world that manages to rein in emissions and hold global average temperatures to something close to the goals of the 2015 Paris climate agreement, that wind shift is likely to mean about 8 percent less Northern Hemisphere wind by 2050 and about 14 percent less by the century’s end, they concluded. On the other hand, tropical regions such as eastern Brazil, southeast Asia or India could see increases of 20 to 40 percent as climate change fuels more wind in those reaches.

Wind energy is a big part of the drive to reduce the world’s consumption of fossil fuels like oil, natural gas and coal, which release heat-trapping greenhouse gases like carbon dioxide. Atmospheric scientist Kris Karnauskas and two of his colleagues at Boulder used a battery of 10 computer models to map what climate change would do to wind patterns around the globe, then compared that to industry figures on generation at different wind speeds.

The projected changes in the Northern Hemisphere stem from the interplay between the cold air of the Arctic and warmer air over the lower latitudes, Karnauskas told Seeker. That temperature differential yields the energy that drives weather north of the Equator. But today, the Arctic is warming at twice the rate of the rest of the globe.

“Because the Arctic is warming so fast compared to the tropics, it’s reducing the temperature difference,” Karnauskas said. “That’s taking away some of the energy that the winds have.”

In the Southern Hemisphere, the driving effect involves the difference between land and ocean temperatures.

“Because of that same principle, as we apply greenhouse gas forcing to the system, the land is going to heat up much faster than the ocean,” he said. That’s likely to result in more wind below the Equator.

Wind turbines produce double-digit shares of electric generation across much of the US Great Plains states, from nearly 40 percent in Iowa to about 12 percent in Texas. In Europe, Denmark already gets about 40 percent of its electricity from wind, while Germany gets more than 17 percent. China’s share is less than 5 percent, but it’s ramping up rapidly as it tries to reduce its emissions and the notorious pollution in cities like Beijing.

The findings were published Monday in the research journal Nature Geoscience. Karnauskas and his colleagues stuck to projections for areas where eight out of the 10 models agreed on the effects, so the results aren’t detailed enough to tell you where to build a new wind farm — but they may help guide future research.

“No matter where you are on the map, you can’t assume that the baseline level of wind energy that we’ve observed for years or a decade or something is constant,” he said.  “A 10 or 20 percent change doesn’t mean, ‘Let’s stop investing in wind energy,’ because that’s not going to be a viable part of the solution. It means, ‘Gosh, if we could make a wind turbine 10 percent more efficient’ — that’s more motivation to do something like that.” 

 

Source: Seeker