The true colours of the wind

An overview of wind power

One of my favourite parts of living in Kingston is the view of the turbines located on Wolfe Island and more recently, the ones on Amherst Island.

A painting (by me!) capturing 3 of the 26 wind turbines on Amherst Island during a stormy summer day.

In my second year of university, I had a design course that featured a group project to construct a small scale wind farm. This was a mandatory course and involved all second-year mechanical engineering students. We were split into different “power companies”, which consisted of five teams of four people. Each team was charged with building a single wind turbine, and then we had to work together within the power company to generate the greatest amount of electricity possible. My team constructed a Savonius-based vertical-axis wind turbine (VAWT), which in retrospect was a terrible idea given the project goal to produce the most electricity. VAWTs generally have a lower efficiency in comparison to a horizontal-axis wind turbine (HAWT), such as the classic three-blade commercial turbines we see everywhere today. Overall I had a lot of fun with this project, from the design phase to the construction phase.

It is perhaps a bit peculiar at first to view wind power as derivative of solar power, but the energy of the sun is exactly what drives wind! As the sun heats up the land and surrounding air, the hot air rises quickly, exerting pressure upwards and leaving a gap, which cooler air rushes to fill. That’s essentially what we feel as a nice cool breeze. The principle behind harvesting energy via wind turbines is also simple. The kinetic energy from the moving air (wind) is ‘caught’ by the turbine blades, causing them to rotate via transfer of energy. The blades are connected to a rotor leading to a main shaft, and this shaft then turns a generator, creating electricity via electromagnetism.

Even though the fuel source is free, the wind is inconsistent in time and space, the latter of which is highlighted in the following map depicting the mean wind speed across Canada:

As with all natural resources, constructing infrastructure for wind energy makes more sense for certain parts of Canada over others. The geographic wind patterns are particularly important to consider because with increased wind speed, wind turbines generate electricity with a higher efficiency. Wind turbines also have a cut-in speed (below this they will not generate electricity) of about 3.5 m/s, and then a cut-out speed (usually above 50 m/s) to avoid damage1.

Canada’s currently installed capacity for wind power sits at 13,413 megawatts (MW), or enough to power 3.4 million homes2. The CanWEA vision is to achieve 20% of our electricity needs from wind power by 20253. PEI is already ahead of the curve, having produced 27% of its electricity from wind in 2019. Wind power holds plenty of advantages – aside from being a sustainable and clean fuel source, it is one of the lowest-priced energy sources available, and it creates plenty of jobs centered in rural areas.

There are some negative aspects to wind turbines, though it seems a lot of these are rooted in public perception. Wind turbines generate noise, which mainly comes from the blades rotating through the air, resulting in a weak but characteristic swish. But cars certainly make more noise than turbines! There are guidelines in place for how close a wind turbine can be to residential areas (at least 300 m away – at this distance the sound is almost equivalent to a refrigerator hum, and at this point in time I believe everyone owns a fridge). Researchers have struggled to find a direct link between reasonable proximity to wind turbines and quality of human health4.

Another drawback of wind (and solar energy to a lesser extent) is the intensity of land use for energy production: the amount of land required for a wind project is typically 75 acres per MW of capacity (however, this is a highly variable statistic)5,6. For comparison, nuclear power only requires 13 acres per MW, a level similar to coal and natural gas.

Only a small portion of the construction of wind farms directly impacts the land (i.e., the turbine’s foundation, utility roads). Nevertheless, construction of any form of the built environment inevitably leads to some form of habitat alteration. Yet when considering the enormous habitat loss that is directly caused by the burning of fossil fuels and production of greenhouse gases (and the resulting climate change), there isn’t really an argument to be made here. How we end up using the precious natural environment is one of the most important considerations for ensuring the healthy future of our planet.

It will come down to a strong policy framework and engagement with all Canadians to ensure effective expansion of Canada’s wind power capacity and take full advantage of this plentiful resource. Regardless, we will certainly continue to move in more sustainable directions for our energy production, but here’s hoping we pick up the pace!

References

  1. http://www.hydroquebec.com/learning/eolienne/
  2. https://canwea.ca/wind-energy/installed-capacity/
  3. http://www.energybc.ca/cache/wind2/www.canwea.ca/images/uploads/File/Windvision_summary_e.pdf
  4. https://www.pbs.org/wgbh/nova/article/can-wind-turbines-make-you-sick/
  5. https://www.saskwind.ca/
  6. https://www.strata.org/pdf/2017/footprints-full.pdf

Further Reading (Link to CanWEA Website)

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