Zero Pollution and the Wind is Free

Wind power is clean energy.  It has the lowest carbon footprint and lowest overall environmental impact of any energy source.  It produces ZERO pollution and is powered by a renewable energy source: the wind.

Theresa standing in front of the massive 3 MW energy generating wind turbine

When I see wind turbines, I get excited.  I am inspired by the massive turning blades producing clean, pollution-free energy.  So it was a thrill when we visited the Bear Mountain Wind Park in Dawson Creek, British Columbia. In the above picture, I’m standing at the base of Turbine #34 (click on this and any picture for a larger version). 

The wind turbines located on the ridge of Bear Mountain

Each of the 34 wind turbines on Bear Mountain is 256 feet tall. Each blade is 135 feet long and weighs 7.7 tons.  The turbines are manufactured by Enercon.  One turbine produces 3 MW (mega watts) of power and the 34 turbines together produce enough energy to supply 35,0000 homes with electricity. 


The wind turbine rotates on the shaft and the blades pitch to maximize the amount of wind turned into power

Wind turbines are designed to maximize the energy captured from the wind.  They generate power by converting the kinetic energy (energy in motion) of the wind into mechanical energy in the gears, which is converted to electrical energy in the transmission lines.  The wind turbine blades are positioned facing the wind.  As the wind changes direction, a weathervane device called an anemometer mounted on the back of the turbine senses this change and sends a signal to a small computer located inside the turbine to rotate the turbine so that it is always facing the wind. The turbine blades are designed like airplane wings, with one side thicker than the other.  This creates uneven pressure as the wind passes over the blade, creating lift on one side of the blade which causes the blades to rotate.

These utility-sized blades rotate at about 18 rotations a minute, which is too slow to generate electricity.  To increase the rotations, the three blades are connected to a shaft, which is connected to a series of interlocking rotor gears that converts the 18 rotations per minute to 1,800 rotations a minute.  The generator converts this mechanical energy to electrical energy.  The rotor gears turn a cylinder of insulated wire coils located inside a magnet.  The spinning coils inside the magnet creates an electromagnetic conductor, which generates an electric current.  This electric current is passed to through transmission lines into the power grid.

The wind quality in the Bear Mountain region is among the best found anywhere, with sustained winds between 5 and 25 mph. In order for wind energy to be economical, the wind farm must be sited in a location that has sustained wind blowing at high speeds.  Wind speed is critical because in the physics equation for generating power (Power = k Cp ½ ρ A V3 ), speed (V for velocity) is cubed.  This means that changes in wind speed have an exponential effect on power generation.  This is why many wind farms are placed on top of geographic features such as mountain ridges, to take advantage of stronger winds.  Similarly, wind turbines placed on flat plains with no obstacles or offshore benefit from higher wind speeds.


A coal processing plant located in Grand Cache, British Columbia

As we drove through Grand Cache, British Columbia, we spotted their #1 industry: coal mining and processing.  Electricity from coal comes at a high cost to society and the environment due to emissions released into the air such as SO2, NOx, and mercury. The Harvard Center for Health and Global Environment department conducted a life cycle analysis to determine the full cost of coal power generation, including external costs paid by society (not by the coal plants) in the form of health and environmental damages. This research estimated the cost to the U.S. public at between one-third and one-half trillion dollars annually, of which a large portion was due to pollutants released into the atmosphere. Conversely, wind power has the obvious advantage of generating zero pollution and CO2 emissions. Each megawatt of wind energy displaces two-thirds of a ton of CO2 that is not produced by burning coal. 

Fox in the woods around Wind Turbine #20

One of the other advantages of wind is that the land under the turbines can be used for farming, ranching, recreation and forestry and is still very viable wildlife habitat.  As testament to the minimal environmental footprint of wind power, we watched this fox hunting at the base of Wind Turbine #20.  Bear Mountain continues to be the home of mule and whitetail deer, moose, bear, eagles, ravens and hawks.  In fact, the turbines, access roads and transmission stations at Bear Mountain Wind Park use only 62 acres of this several thousand acre recreation area.

Wind power has disadvantages, as no energy solution is perfect.  The primary drawback of power sources like wind and solar is called intermittency, which means that the power source is available part of the time.  Said simply, the wind does not always blow and the sun does not always shine yet, electricity is needed all the time. Intermittency can be solved by several methods such as geographically dispersed intermittent power stations, energy storage or  baseload sources, such as geothermal, natural gas, coal or nuclear.   At Bear Mountain, the electrical grid supplies electricity when the wind is not blowing, likely from traditional sources of energy such as coal or natural gas.

Far more bird deaths are caused by cats than by wind turbines

A second disadvantage many wind energy opponents mention is the number of birds and bats killed by being struck by the wind turbine blades.  The tips of the blades are travelling very fast, at approximately 250 miles per hour.  However, far more birds are killed by buildings, windows and house cats, as the above chart shows.  I talked to an Enerco technician working on the elevator in Turbine #22.  He said that the Dawson Creek University conducted a study in 2010 and determined that the 34 turbines killed 30 bats, 15 birds and 1 raptor.  This is not insignificant but it is far fewer deaths than those caused by other human activities.


Timm hiking along the cliff line in Bear Mountain Wind Park

Wind power is now cost-competitive with all other energy sources, even without allowing for the value of its low environmental impact. It is the fastest growing energy option in the world and will soon be the least expensive.  It’s pure, clean, green energy.

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