“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 Effects” Science 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, weather” San 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.