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Nano Climate Change: Another Issue for Industrial Wind

By Mark Lively -- August 2, 2011

“In any case there is an irony: environmental policy in the name of countering the human influence on macro climate is creating a substantial human influence on micro climate. If the natural climate is optimal, as some but not all ecologists believe, then industrial wind turbines add to the problem of man versus nature.”

I have long heard of micro-climates, isolated areas that have slightly different weather patterns than the surrounding larger area. I best remember hearing of the micro-climate of Northern California’s Napa Valley, a micro-climate that makes the area so good for growing grapes.

For the last several years, Somnath Baidya Roy has been pushing the concept that wind farms can affect the weather. While at the department of civil and environmental engineering at Duke University, Roy said:

“Large wind farms can significantly affect local meteorology.” He studied these massive machines and believes wind farms can actually impact our weather because wind turns the blades of the turbine around a rotor, which helps generate electricity the blades create a lot of turbulence in the wake.”

Roy also said at that time:

“It’s something like the wake from the propeller of a boat. Now this added turbulences mixes air up and down and creates a warming and drying effect near the ground.” He says the affects can be felt for miles and could have an impact on air conditioning costs and more money may have to be spent on irrigation of nearby crops.”

Wind farms tend to impact the weather more at night, which is when the wind is usually stronger and the most energy is generated.

WHAT THEY FOUND: Large groups of power-generating windmills could have a small influence on a region’s climate. All large wind turbines disrupt natural airflow to extract energy from wind. During the day, the effects from the disturbed airflow are negligible, since natural turbulence mixes the lower layers of the atmosphere. But the researchers found that in the predawn hours, when the atmosphere is less turbulent, a large windmill array could influence the local climate, raising temperatures by about 2 degrees Celsius (about 4 Fahrenheit) for several hours. The rotating blades could also redirect high-speed winds down to the Earth’s surface, boosting evaporation of soil moisture.

Wind Farms Impacting Weather: Environmental Engineers Detect Turbines’ Turbulence EffectsScience Daily, 2005 October 1.

Roy is now atmospheric sciences professor at the University of Illinois at Urbana-Champagne and is continuing his research, but with some different findings. A study “Impacts of wind farms on surface air temperatures,” published in late 2010 in the Proceedings of the National Academy of Sciences, written by Roy and Justin J. Traiteur now shows:

Downwind of a wind farm, turbines create lower local temperatures during the day and higher temperatures in the early morning and at night, the study indicated.

The cooling effect could mean a temperature of about 86 degrees Fahrenheit instead of 93.2 during the day near the surface.

The warming effect could mean about 69.8 instead of 68 degrees at night.

Scientists studying wind farms effects on temperature, weatherSan Diego Times, 2011 June 17

The nano-climate effect of wind farms has been observed elsewhere, even with off-shore wind farms. Retired garage owner Mike Page, 70, of Strumpshaw, Norfolk, England took pictures of the fog created by an off-shore wind farm the scene from his Cessna 150 light aircraft, said:

‘The spinning blades whip moisture into the air like giant egg mixers.’

‘It definitely occurs several times a year, sometimes gathering upwind of the turbines and sometimes downwind depending on the conditions.’

‘The strange thing is that you will see this mist around the turbines while it is a bright clear day on the beach just a couple of miles away.’

‘It is a fascinating example of how wind farms create their own micro-climate. It is the same as any geographical feature affecting the weather.’

The climate changers: How wind turbines make their own clouds” Daily Mail, 2010 February 20.

Page’s description of the fog hanging off the coast around the wind mills reminds me of my wife’s description of the fog banks hanging off the coast of the Southern California of her youth. The differences include that one is a man made phenomenon and the other natural and that one is an island of fog and the other a long ridge of fog.

As with many issues involving man’s impact on the climate, the jury seems to still be out on the impact of wind to create nano-climates.  A more important issue is whether those nano-climates are better or worse for local residents than the broader climate of their area, the climate without the nano-climate effect of wind.

In any case there is an irony: environmental policy in the name of countering the human influence on macro climate is creating a substantial human influence on micro climate. If the natural climate is optimal, as some but not all ecologists believe, then industrial wind turbines add to the problem of man versus nature.


Mark Lively is a consulting engineer in Gaithersburg, MD, specializing in the pricing of electricity and natural gas.  He has an SB in Electrical Engineering from MIT and an SM in Management from MIT’s Sloan School.  He worked for five years at American Electric Power in New York City and fifteen years at Ernst & Ernst’s Washington Utility Group before starting his own firm in 1991.  The US Postal Service used his 1980 rate case model as recently as 2005.  His Committed Unit Basis model for evaluating long term cogeneration contracts was adopted by the Texas PUC in 1984 and used by HL&P for large contracts.  His Wide Open Load Following pricing model applies to unscheduled flows of electricity, such as sudden bursts or lulls by wind generators or for intra-minute operation of storage systems.  His web site is www.LivelyUtility.com.


  1. Jon Boone  

    It was the Canadian wind pusher, David Suzuki, who some years ago probably was the first to pose a thought experiment in which wind warmed the surrounding climate. As Mark implies, the truth about this could only be revealed after much inquiry, since it is so complex.

    I would suggest that the overarching concern is not humankind versus nature, as if the two are separate and discreet entities, but rather the way culture affects wild nature. We are not outside nature; our technology is very much an extension of nature. To me, as in most things, the real question redounds on civility: how we choose to live with the diverse biota surrounding us, what accommodations we grant to others, and how we limit our actions so that the larger world might prosper with us.


  2. Large Wind Turbines | Wind And Solar  

    […] groups of power-generating windmills could have a small influence on a region’s climate. All Large Wind Turbines disrupt natural airflow to extract energy from wind. During the day, the effects from the disturbed […]


  3. Rod  

    Concerned Citizen: The most costly and least producing power on the Planet . I can’t understand what happened to all the Brainiacs that used to stand up and tell the truth even when it went against the grain, but not on this issue. This is the big picture and these things are big and they are many. In the last 20 yrs or so I have noticed the weather changes in the different parts of the country . In the west they have been in place and the wild weather blew in the mid west and the wild weather blew now they want to put them up here build um and it will come ,. This is not a prediction it is only observation of the wild storms that have destroyed thous of homes and killed and maimed 100’s of people .
    These weather changes have nothing to do with climate change dues to green house gas. These change have only gotten dramatic since these turbines have come on line .Just follow the wind farms where they started where they are now East to West, it is amazing what the big picture looks like .


  4. Niels Tieland  

    Taken from http://www.preservearticles.com/2011111217127/the-temperature-inversions-may-be-classified-in-the-following-types.html

    Turbulence and convective inversion:

    This type of inversion is produced at altitudes above the surface by mechanical processes. Turbulence and convection are the contributory factors in causing this type of inversion.

    Because of the frictional forces eddies form in the lower layers of atmosphere which transport lower air to higher levels and bring back the upper air to the lower levels. Convectional currents set up in the air near the ground are mainly responsible for the exchange of air between upper and lower levels of the atmosphere.

    The phenomena of turbulence and convection cause a thorough mixing of the atmosphere in turbulent layers. However, the turbulent or convective mixing is limited to a certain height beyond which it does not and cannot penetrate.

    It is at this height that the convective inversion is formed. In the process of vertical mixing the air carried upward is cooled adiabatically. Similarly the air brought downwards heated at the same adiabatic rate.

    After a prolonged mixing in the atmosphere, the air at the maximum height of turbulent penetration becomes colder than what it was before, and that at the bottom of the turbulence layer will be warmer than what it originally was.

    The transition from this cold upper part of the turbulence zone to the air above with its temperature unaffected by adiabatic cooling comprises a temperature inversion.

    Clouds, if they ever form in this inversion layer, are of stratus or stratocumulus type. In certain situations, turbulence in association with heat from the ground leads to the formation of cumulus or cumulonimbus clouds.

    Turbulence inversion may occur at a low level or it may form at very high altitudes. In case the inversion has formed at lower levels, smoke, dust particles and other pollutants are carried up to the inversion where they spread beneath the inversion layer and form distinct smoke or haze lines in clear weather.

    On the other hand, the anvil-shaped upper portion of cumulonimbus clouds is the result of inversion at considerable heights.

    It may be interesting to note that stratiform clouds appearing in the sky are indicative of the presence of an inversion layer above them. Sometimes the upper air inversion, by imposing a restriction on their vertical growth, makes the cumulus clouds stunted in appearance.


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