Demystifying science | Wind turbines along highways?

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Why don’t we install wind turbines along highways, as is done elsewhere?
– Benoît Le Nabec

This approach is indeed attracting a lot of interest. But it uses vertical axis turbines, the development of which is less advanced.

“These are vertical axis turbines,” explains Bianca Viggiano, mechanical engineer at Polytechnique Montréal. There are some in Türkiye, possibly in Malaysia too. These are low power (wattage) systems that can power street furniture. If they are urban highways, they can easily be connected to already existing electricity networks. »

Vertical axis turbines are less efficient than those we usually see, whose axis of rotation is horizontal, with vertical blades. “The wind is stronger at altitude and wind power increases proportionally with the cube of wind speed,” adds M.me Viggiano.

The transformation of wind energy into electricity is simply worse than for horizontal axis turbines, 40% versus 50%.

Bianca Viggiano, mechanical engineer at Polytechnique Montréal

Vertical axis wind turbines, however, have an advantage: they are better able to take advantage of the wind despite turbulence. “With a horizontal axis wind turbine, the blades must face the wind,” says M.me Viggiano.

As they are less used, there is less progress on optimizing vertical axis wind turbines. Mme Viggiano directed The Press to specialists in this technology at the Sandia National Energy Laboratory in the United States.

Fuel consumption

“Vertical axis wind turbines designed for intermittent gusts of wind, to take advantage of highway turbulence, would require very strong blades and a structure,” said Kevin Moore, a mechanical engineer at Sandia. “It would probably be economically unviable. For roads where there is heavy traffic, and therefore constant wind, the transformation of wind into electricity by wind turbines would reduce the positive impact of wind on cars. The latter should consume more fuel. »

A rough calculation by Mr. Moore shows that using this additional fuel to run a generator would produce two and a half times more electricity.

Watch highway wind turbines in Türkiye (in English)

A 2015 master’s thesis from a student at the Technical University of Delft in the Netherlands also explored the question of the impact of highway wind turbines on car fuel consumption. He argued that if wind turbines were installed in the middle of a highway, the headwind from cars traveling in the opposite direction would be reduced, with no effect on fuel consumption. He calculated that 50,000 wind turbines on a 110 km highway would generate 23 MW, 15 times less than the Seigneurie-de-Beaupré wind farm, the largest in Canada.

A report from the North Carolina Department of Transportation calculated that energy produced by highway wind turbines would initially cost five times as much as solar panels, but that advances in the design of vertical-axis wind turbines could change the calculation. That report noted that wind turbines would generate electricity during the early evening rush hour, while solar panels would not.

Vertical axis turbines were tested by Hydro-Québec in Cap-Chat, in Gaspésie, and in Havre-aux-Maisons, in the Magdalen Islands, 30 to 40 years ago. That of Cap-Chat, the largest in the world, is still there, but not functional, and that of the Islands was dismantled in 2019. Vertical axis wind technology has been used since the days of windmills.

Vertical wind turbines over the centuries

  • The Cap-Chat vertical axis wind turbine is the largest in the world, with a height of 110 m.

    PHOTO WIKIMEDIA COMMONS

    The Cap-Chat vertical axis wind turbine is the largest in the world, with a height of 110 m.

  • The Îles-de-la-Madeleine vertical axis wind turbine before its dismantling

    PHOTO WIKIMEDIA COMMONS

    The Îles-de-la-Madeleine vertical axis wind turbine before its dismantling

  • In the 1990s, a vertical axis wind farm was in operation in Alberta.

    PHOTO TAKEN FROM THE APEGA SITE

    In the 1990s, a vertical axis wind farm was in operation in Alberta.

  • Scottish engineer James Blyth designed a vertical axis wind turbine at the end of the 19th century.

    PHOTO WIKIMEDIA COMMONS

    The Scottish engineer James Blyth designed at the end of the 19th centurye century a vertical axis wind turbine.

  • The vertical axis windmills of Nashtifan, Iran, were built in the 9th century.

    PHOTO WIKIMEDIA COMMONS

    The vertical axis windmills of Nashtifan, Iran, were built in the 9the century.

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  • 17%
    Proportion of global wind energy produced offshore

    SOURCE: International Energy Agency

    50%
    Proportion of global wind energy produced in China

    SOURCE: International Energy Agency


reference: www.lapresse.ca

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