Wind speeds are getting faster worldwide, and that's good news for renewable energy production — at least for now.
A study published yesterday in the journal Nature Climate Change finds that winds across much of North America, Europe and Asia have been growing faster since about 2010.
In less than a decade, the global average wind speed has increased from about 7 mph to about 7.4 mph. For the average wind turbine, that translates to a 17% increase in potential wind energy. That might explain about half the increase in U.S. wind power capacity since 2010, researchers say.
The study may help put to rest a scientific debate that's perplexed researchers for years.
Before global wind speeds picked up in 2010, they had been decreasing for several decades, starting in the 1970s. Scientists floated a variety of theories about the "global stilling," as it came to be called. One of the most popular ideas suggested that increasing urban development and other land-use changes had altered the surface of the Earth, making it rougher and increasing the amount of drag acting on the flow of air around the world.
But if that were the case, wind speeds should still be slowing down now — not speeding up. The recent reversal suggests that some other factor must be playing a bigger role.
The new study points to large, natural climate cycles as the likely culprit.
Using models to investigate the factors that influence the behavior of global winds, the researchers found that big climate patterns — which affect temperatures in certain parts of the world — have a major influence on wind speeds. Temperature differences between neighboring regions, or between the ocean and nearby land areas, can affect the flow of air.
For instance, the researchers found that wind speeds tend to be slower across much of the Northern Hemisphere when temperatures are warmer in parts of the tropical Atlantic and the western Pacific and over Greenland.
Temperatures all over the Earth are steadily rising as a result of human-caused climate change. But within that larger, long-term warming pattern, temperatures in these regions also tend to naturally cycle back and forth between warmer and cooler periods, sometimes lasting decades at a time.
The authors of the new study suggest that a shift between certain natural climate cycles may have helped trigger the switch from slower to faster winds.
If they're right, the speeding-up trend could continue for another decade or longer, until the next major shift occurs. That could be a boon for the wind power industry in the near future. If the current pattern continues, the authors suggest that average global power generation could increase by as much as 37% by 2024.
The study also raises some important points about long-term wind power planning. If natural climate cycles can cause such major changes in global wind speeds, the industry should plan for potential ups and downs.
And if climate fluctuations really do have such a big effect, there's also the question of how future climate change may factor in.
While some theories are more controversial than others, recent studies have drawn connections between climate change and the behavior of the Northern Hemisphere jet stream, the westerly winds around Antarctica and other air circulation patterns around the world. And some modeling studies have suggested that continued warming could cause substantial shifts in the regions with the most potential wind power around the world — namely, declines in the Northern Hemisphere and some potential gains in the global South.
Determining where these changes could occur is critical for long-term planning purposes, including where to invest in new wind farms and what to expect from existing ones. And if the new study is accurate, both natural climate cycles and the ongoing impact of global warming should be taken into account.
Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news a twww.eenews.net.