Jet stream unlikely to supply much energy
The lack of friction at high altitudes mean that wind turbines won't have much power to grab and convert into electricity.
Tue, Dec 20, 2011 at 10:28 AM
Photo: Wikimedia Commons
High-altitude winds might not be the potential source of power that some bold thinkers had hoped – and grabbing even the smaller-than-expected power that is available could wreck the planet’s climate. Those are the conclusions of German scientists, who based their pessimistic view on atmospheric energetics and climate simulation models.
Yes, four to 10 miles above earth the jet stream moves at a constant speed of more than 55 mph, the Max Planck institute researchers said. But one of the factors that allows the air to move so quickly and consistently also explains why high-altitude winds could have scant wind-power value: There’s very little friction at those altitudes, the researchers said. That means it takes only small amounts of energy to drive the winds, which in turns means there’s actually very little power available for turbines to grab.
“It is precisely this low energy requirement that limits the potential for using the jet streams as a source of renewable energy,” Axel Kleidon, head of the Independent Max Planck Research Group on Biospheric Theory and Modelling, said in a statement.
Kleidon said his group estimated that jet streams have an output of 7.5 terawatts (one terawatt equals a million megawatts). “This means that they generate 200 times less usable wind energy than stated in previous studies, and only about half of humankind’s primary energy requirements, which totaled about 17 terawatts in the year 2010,” the researchers said.
What’s more, the researchers said, grabbing high-altitude energy would alter the balance of forces in Earth’s atmosphere to potentially disastrous effect. “If we used wind turbines to take 7.5 terawatts out of the atmosphere at the level of the jet streams, about 300 terawatts less energy would be generated in the atmosphere as a whole,” said Lee Miller, lead author of the study. “This would have a drastic impact on temperature and weather.”
The researchers’ paper, “Jet stream wind power as a renewable energy resource: little power, big impacts” [PDF], was published in the journal Earth System Dynamics.
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