Wind Power: Reaching the Physical Limit?


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Arrays of wind turbines may generate less energy than previously thought. Photo by Morten Mitchen Larod on Flickr

Arrays of wind turbines may generate less energy than previously thought. Photo by Morten Mitchen Larod

According to a new study published in Environmental Research Letters, wind turbines may generate less power than previously thought. Some simulations show that about 1 W/m2 may be the limit and the turbines cannot produce more energy due to a slowing effect that the turbines have on the wind. What can we do about this issue?

Wind Power

Wind power, the generation of energy from the wind, is an alternative way to produce energy without burning fossil fuels. As the turbines do not emit carbon dioxide (CO2) generate energy, we consider wind power more environmentally friendly, and encourage the development of these technologies because it is a renewable source. The stock of wind will not run out, in contrast to what will happen eventually with fossil fuels, such as natural gas or oil.

Increasing Energy Production

In recent years, the production of energy using wind remarkably increased. According to the European Wind Energy Association, new plants were installed in every EU country in 2012, with an annual capacity growth rate of 11.6 %. Thanks to this,  about 7 % of the total electricity consumed in the EU in 2012 was generated by wind turbines. This proportion was even higher for countries like Denmark and Portugal (27 % and 17 %, respectively).

Problems with Wind Power

Despite these encouraging results, however, there are still doubts about more widespread use of wind power. The main problem is that the source of the energy, the wind, may not be continuous and reliable, as it depends on the atmospheric weather. There is also a controversy about the possible effects that wind turbines have on the fauna of the areas where they are installed. In particular, they may cause bird deaths, although analysis regarding this point has had contrasting results.

Reaching the Limit?

In addition to these problems, a new study shows that the actual capacity of turbines to generate electricity may be overestimated. The school of Engineering and Applied Science of Harvard University performed this research in collaboration with University of North Carolina-Charlotte. The study investigated in detail the alteration in wind flow caused by the presence of the turbines, and how this may affect energy production. The results were published in Environmental Research Letters on February 25, 2013.

When a turbine extracts energy from the wind, it creates a plume of low velocity wind downstream; this means that the wind strength is lower. With a weaker wind, less energy is generated. The study used a model to quantify this decrease.

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