Environmental Blow from Wind Farms

Mann, Jakob, and Jonas Teilmann. “Environmental impact of wind energy.” Environmental Research Letters 8.3 (2013): 035001.  Doi: 10.1088/1748-9326/8/3/035001

Figure 1: Yearly production of electrical energy by wind farms globally.  The red line is the doubling time, three years.
Figure 1: Yearly production of electrical energy by wind farms globally. The red line is the doubling time, three years.

Wind farms are a great source of cheap energy.  In the modern world, wind farms support 2% of the global electricity demand (compared to 13% from nuclear energy). Future projections estimate that wind energy could satisfy up to 10% of the global energy demand within a few decades.  As wind farms grow in popularity there are rising concerns regarding sustainability, ecological pressures, health concerns, and environmental impacts that must be addressed, for example, the noise level, the capacity of wind extracted, and the impact of sea surface temperature.

Wind farm are noisy places.    They are noisy when being planned as a result of political differences and financial limitations, they are noisy during construction when the monopile foundations are rammed into the seafloor, and they are noisy when they are up and running from both mechanical vibrations and the friction of the wind on the blades.   All this noise has caused concerns as to the impacts on human health, and the impact the noise has on the presence of harbor porpoises and seals.   As for human health, available research observes no direct impact besides the aggravation and potential disturbance to sleep (although some may argue that loss of sleep can impede health if dramatic enough).  The impacts on porpoise populations are a little more obvious.  Observations from various wind farms agree that the intense sound made during the construction of a wind farm drives the porpoise populations away and that after construction there is a waiting period before the population returns, if it does.   Displacing a species from an ecosystem is like removing a link from a chain where every link represents a species: before the species is removed, the ecosystem is a well-linked dynamic system, but after removal the connections are broken and new links must be established.

It is important to note that apart from the noise disturbance the existence of a wind farm has the potential to be helpful for porpoise and seal populations because restrictions on fishing and shipping traffic, and increased real estate for benthic organisms, make them a great source of food with minimal danger of getting caught in fish nets or colliding with ship traffic.    On the down side of that, one must ask ‘by restricting the fishing grounds are the local fisheries damaged at a greater cost than what we save from the wind farms?’, and we should also consider what kind of impacts increased populations of benthic species might have.

In addition to the local, adverse effects of wind power on marine ecosystems, larger scale concerns regarding the wind energy extraction capacity of wind farms and the role that offshore wind farms will have on ocean surface temperature have been raised. To address this question, sophisticated models called atmospheric computer experiments are used.  Researchers have noted that after a certain number of windmills a wind farm will reach a cap on the extractable wind energy (i.e. having more windmills will not increase the wind energy retrieved).  Using the models they have also predicted that wind farms may cause slight cooling of sea surface temperature, an effect that has the potential to have ecological impacts

In conclusion, wind farms are a dependable source of energy. Although the ocean is a great place for wind, offshore development has consequences on for the environment and its inhabitants that require further investigation and observation.



2 thoughts on “Environmental Blow from Wind Farms

  1. I think it is important to note that the placement of wind turbines is the limiting factor for the energy extraction cap. For example, if you have a horizontal line of turbines, and the wind is continuously parallel, adding more will always add more extracted energy, without a limit. It is the closeness and lateral “stacking” of turbines that limits the effective energy extraction. So to clarify the point in the article, on any given plot of land (or ocean), there is a cap on energy extraction based on the ratio of land to turbines, but given an infinite area, there is no cap. This is, of course, a nit-picky detail, but I think it is an important detail nonetheless.

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