Could Windmills Alter the Weather?

Wind turbines along the Buffalo Ridge in rural southwest Minnesota (2004)
Wind turbines such as these along the Buffalo Ridge in rural southwest Minnesota (2004) may alter large-scale wind flow over land.

Wind turbines are quickly becoming the favorite green energy source of many nations the world over as they are often considered to be virtually zero-impact.  But current research indicates wind turbines may not be as green as once thought.

Wind turbines do not block rivers or inhibit migratory species as hydroelectric dams do.  They do not emit greenhouse gasses or exhaust our dwindling supplies of nonrenewable resources such as oil or coal.  Wind turbines  generate seemingly unlimited, clean energy.  While some research has indicated wind turbines may have harmful effects on birds or other unintended consequences on the environment, most of these have been generally excused as minimal or otherwise disputed compared to the relative benefits of wind energy.  But a team of researchers from the University of Maryland have found that large-scale use of wind turbines as a power source may have an impact on our environment directly opposite that which they purport to minimize:  Climate change.

Altering air flow and wind patterns

Conservative estimates are that it would take at least a quarter-million wind turbines to meet the United States’ energy needs.  Installation of such an enormous array of wind turbines would have a profound impact on the atmospheric wind flow over the surface of the United States and perhaps even other nations.

Scientists Daniel Barrie and Daniel Kirk-Davidoff of the University of Maryland have shown that installation of a massive wind farm covering the bulk of the central United States into central Canada would effectively “steal” energy from the atmosphere.  As anyone who has studied basic physics may recall, in a closed system such as the Earth’s atmosphere, energy is conserved, that is, it cannot be created or destroyed.  As air flows through the blades of a gigantic, 300-foot wind turbine tower, the wind energy turns the blades.  This energy is robbed from the atmosphere, effectively slowing the wind speed proportionally.  The greater the array of wind turbines, the more energy is removed from the atmospheric flow and the slower the ambient wind will travel.  Slowing wind speeds by 5 or 6 miles per hour – while it sounds negligible, could have significant impacts on the large-scale atmospheric flow and yield consequences we do not yet understand.

Altering Ocean Currents

An offshore wind farm such as this one may have profound impacts not only on the air flow, but also on the ocean currents beneath the surface.
An offshore wind farm such as this one may have profound impacts not only on the air flow, but also on the ocean currents beneath the surface.

In another recent project on the impacts of wind power on our environment, Goran Brostrom of the Norwegian Meteorological Institute in Oslo has published research indicating that offshore wind farms, while perhaps less unsightly and intrusive than their land-based counterparts, may have a small yet profound impact on ocean currents in their wake.

When air flows through wind turbine blades, the path that the flow takes is slightly altered.  The net result is that there is turbulence down wind from the turbine blades.  When this turbulence occurs, rather than the ordinary laminar flow, the surface of the ocean is impacted.  This turbulence over the ocean water can cause a phenomenon known as upwelling whereby deeper ocean water is drawn up to the surface as surface water is driven down to replace it.  When the ocean “turns over” in this manner temperature flow within the body of water is altered.  Altering the upwelling patterns of an otherwise undisturbed body of water may have impacts on the currents that naturally exist as part of the large-scale flow.  As with the atmospheric air flow impacts of large-scale wind farms, the overall impact of increased ocean current upwelling is not fully understood.

13 comments

It is basic physics. Consider the butterfly effect. Energy removed by wind turbines will not go into thunderstorms, etc. I have suggested this to meteorologists for quite some time. As humans, it is not our position to try to control what God has initiated, but to adjust. As the cycles change, we must change. Take the blooming politics out of scientific decisions and quit the stupid hype of pushing uncertain theory as fact to fit political agendas. Most of the world and American population is ignorant in scientific matters, but they sure can be mislead by lies and fast talking politicians with teleprompters.

I am a meteorologist and wanted to let readers know that this article, while interesting, is the farthest thing from “true.”

99% of weather — in the sense of meteorology, weather forecasting, processes that create/affect weather — happens above 1,000 feet from the ground, from basically 850mb on up to 200mb. Wind currents on the ground account for a minutia of energies used in all processes of weather. The presence of wind mills will not affect the heat radiated from the ground due to solar insolation, so it’s not like convective processes (storms) are affected. Oceananically, the presence of even millions of wind mills would have an unmeasurable effect on “currents” and would have no effect no our lives on Earth.

What will have effect is the continued emittance of green house gases into our atmosphere from coal burning and oil consumption.

This “report” seems like something sponsored by Exxon.

Even if the predictions were true, to suggest that people would put up with a large swath of wind turbines up and down the continent is ridiculous, so there is no point in suggesting this and then arguing against it. Nobody sane is suggesting that we replace all our energy generation with wind power. Instead most scientists and energy experts I’ve been reading have said we are going to have to use a number of different energy sources.

Why are people worried about the disturbance of the wind? Who takes into account the billions of trees that have been cut down. I have been to Illinois where land with such rich soil has been virtually striped of trees so the farmers could plant two more rows of corn or soy, among other places for other reasons. Perhaps those trees slowed some wind down at some point so if the wind turbines slow it down… so what “That” is the way it was meant to be.

I am also a meteorologist and agree with Jack W. that the potential impact is overstated. The “weather” is a result of the earth’s atmosphere trying to correct energy imbalances (kinetic and latent) built up by differences in solar insolation over the earth’s surface. The sun and moisture are the drivers. The amount of energy in the atmosphere (again latent and kinetic) involved is huge (atomic bomb level of energy for a single supercell thunderstorm) compared to what is taken out by the wind turbines. And most of the energy in summer thunderstorms is driven by the release of latent heat from condensation in the storm, not the wind itself. So “stealing” some energy from the wind will have negligeable impact on the creation or sustainment of thunderstorms. Most changes would only noticeable on the micro-scale and will not impact the larger scale weather systems with any significance. As Amanda points out, there are many more man-made changes that would have a larger impact, such as deforestation (which also changes the surface albedo (reflectance of solar insolation) of large areas of land and the expansion of cities (heat island effects) than worrying about inconsequential energy loses from large numbers of wind turbines.

If you had told the first pioneers of the oil drilling industry back in the late eighteen hundreds that the use of fossil fuel would eventually lead to climate change the ywould have dismissed your arguments with very similar ones to those posted here, and yet here we are only one hundred or so years later with a world thats heating up alarmingly. No one knows how much energy would need to be taken out of the atmosphere before the weather patterns would start to change, but only a fool would ignore the lessons of the recent past, as the planets current guardians we need to stop being so arrogant and take more care over how we harness its resources !!

As an engineer the question of the effect of wind turbine electricity generation on atmospheric air movements and subsequent loss of atmospheric energy has troubled me for some years. It appears to me that the overwhelming need to produce cheep electricity has overtaken any sense regarding the final effect to planetary energy transformation.
This applies not only to air movements but also energy accumulated from tidal restrictions, wave power generators and losses to the planet of solar energy from the use of power cells.
By removing the energy that the Earth generates within its own ecology we will directly effect the movement of the energy through many different ecosystems and ultimately destroy them or change them dramatically enough that they no longer suit our needs.
It is just common sense really. The real problem is the number of people demanding power from these finite sources and the issue will only be exacerbated further with time and population increase.
We need to work models that look at predictive effect based on the use of many types of power generation in unison so we may derive the most effective groups of power generation systems that together cause the least effect, however, at the moment it just seems to be a free for all to generate electricity without the thought or collaboration between companies and countries. This will be disastrous if continued.
I wish I had the funding and equipment to forecast the effects, I believe the world would be surprised, amazed and frightened at the results.
Nick Sarahs

I saw a short clip by a man who claimed that turbins in mass do disturb the flow of the wind driving them. As to spread that wind out, and away further from it’s natfual course. Kind of like the air being drawn into a fan. And where it ends up after passing through it. I have noticed that the regular thunderstorm, rain and snow patterns where I reside have deminished. And have become more prevelant to the North, and South of our area. I live in Ohio. Our vicinity was always known for being towards the end of tornado alley. We before. Always had immense thunderstorms, and slot of winter snow fall. We are seemingly near the end of the swaths of windmill farms along the wind cooridor through the western U.S.. And. Our water has changed drastically. We get very few bad storms. Minimal rain, and snow. As compared to when I was younger. Yet. To the north, and South of us? They are getting more of what we got before. My question? Could this really be due to the windmills? It’s the only change to the lay of the land in the amount of my time on this earth. And I’m 60. It does coincide with the windmill farms being erected. Same time line. It appears to me to be the only real answer as to why we are experiencing the weather patterns we are today. As compared to the patterns we experienced before the appearance of the windmill sites.

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