Wind power has been doing quite well in the last few years. With reports finding the renewable energy is becoming ever more cost competitive in addition to being an environmental hero, wind energy has seen increasingly more farms built, and deals signed.
An unexpected benefit
Now, University of Delaware's College of Earth, Ocean, and Environment professor Cristina Archer has discovered another unexpected benefit of large-scale offshore wind farms bound to make the installations even more popular. It turns out these eco-friendly energy producers may also lessen the often-devastating precipitations caused by hurricanes.
Our simulations show that precipitation in Houston during Hurricane Harvey could have been reduced (-200 mm) with large offshore wind farms in the Gulf. Check out our new paper in Environmental Research Letters https://t.co/CjntP0Otrb via @IOPscience pic.twitter.com/IERoblodoy— Cristina (@WindLady) August 9, 2018
In a university statement outlining the research's details, Archer said that previous studies had illustrated the potential ability of offshore wind farms to harness the kinetic energy from hurricanes in order to reduce the effects of wind and storm surge. However, her study has now shown the farms can also decrease hurricane-related precipitation.
Archer, who is also the Wind Power Associate Director of the Center for Carbon-free Power Integration, chose Hurricane Harvey as her work's example due to its record-breaking precipitation levels. The natural disaster is said to have brought the heaviest rain ever recorded in the United States' history. The output was so bad that Texas' Houston city was flooded.
Wind convergence and divergence
According to Archer, wind farms interfere with both wind convergence and divergence and, as a result, can indirectly affect precipitation. "Think about convergence like when there's traffic on a freeway, and everybody is going fast and then all of a sudden, there's an accident, and everybody slows down. You get a convergence of cars that back up because everybody slows down. That's the convergence upstream of the offshore wind farms," explained Archer.
Wind converge leads to increased precipitation while divergence reduces it. "Divergence is the opposite effect. It causes downward motion, attracting air coming down, which is drier and suppresses precipitation. I was wondering what if that would also happen when there is an offshore farm?" said Archer.
So the professor ran numerical simulations and found that past wind farms, a clear divergence was witnessed that successfully suppressed precipitation. "That means, potentially if you have arrays of offshore turbines in an area where there are hurricanes, you will likely see a reduction in precipitation inland if the farm is there," speculated Archer.
The study ran simulations with hypothetical farms featuring 0 to 74,619 turbines and found that the more turbines there were, the higher the precipitation reduction was. And in the end, the hurricanes were essentially robbed of their devastating power.
"By the time a hurricane actually makes landfall, these arrays of turbines have been operating for days and days, extracting energy and moisture out of the storm. As a result, the storm will be weaker. Literally."
The study was published in the Environmental Research Letters journal.