We all know that we have a bit of an energy problem. Traditional methods of creating power, like fossil fuels, cause vast amounts of air pollution and habitat destruction; however, there are a number of new energy sources under development.

Cue the bridge wind turbines...?

Wind turbines have been in the news a lot recently. In 2014, one of the Canary Islands became the first in the world to be powered entirely by wind and water. The feat is quite a notable accomplishment though, full disclosure, the island only has some 10,000 residents to support. Moving to alternative forms of energy will be far more difficult for larger nations, particularly large Western nations that have an economic infrastructure that is based on fossil fuels.

And of course, economics isn't the only issue.

Ultimately, in order to be effective, wind farms need to take up a bit of space. Not only does this result in habitat destruction, it causes difficulties for nations that have high population densities and small land areas. This is where bridge turbines come in. These structures could allow us to generate energy without causing any additional habitat destruction or land usage.

This past week, researchers in the UK published an article in which they used computer modelling to show, for the first time, that wind turbines placed below bridges would be a viable way to harvest sustainable electricity. Just one of these installations would be capable of generating around half a megawatt of electricity (which is enough to power around 450 to 500 homes, depending on where you live and how much energy you consume).

Wind Turbine (Image Credit: Jose Antonio Penas/SINC

In order to determine what kind of structures should be used, the team modeled a number of different turbines. In the end, they discovered that, despite the larger surface area of the big turbines, a number of smaller turbines generate more electricity than large ones do. As a result, they assert that the most effective strategy (in this particular case and only considering energy generation) would be to utilize 24 small turbines stationed under the Juncal viaduct. The team states that this is the best option in terms of both power generation and structural considerations.

However, in the end, we can't leave economics out of the equation.

And when you consider the cost, and the difficulty (and time) increase related to installing a higher number turbines, the benefits get cancelled out. As a result, considering all the factors, the most efficient structure is the one shown in the image above. It includes two turbines of the same size, each capable of generating a quarter of a megawatt. The results have been published in Renewable and Sustainable Energy Reviews.

The Drawbacks?

Some have noted that this may cause a substantial issue for local wildlife. However, there is some debate on whether or not the impact of wind turbines is (or is not) actually significant in relation to bird deaths. Yet, admittedly, we do know that they cause some harm. For example, in Altamont Pass in California, some 1,300 birds of prey are killed each year.

That said, at the very least, there is no indication that these structures will be more detrimental than current wind turbines, and when we compare these structures with fossil fuels, the environmental advantages simply can't be contested. Moreover, the impact that these structures have does greatly depend on where they are placed. As a result, studies can be done beforehand in order to pick prime locations that will not negatively impact local bird populations or interfere with any boating lanes.

The other consideration, which is taken into account by the team, is structural issues that may impact the integrity of the bridge. Modifying bridges effectively will obviously add some economic cost, but the bridges seem to be viable in light of these factors.

They may not dot our landscapes anytime soon; however, at least we are trying to move in the right direction.


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