When the world gets closer.

We help you see farther.

Sign up to our expressly international daily newsletter.

Sources

Capturing Energy From A Flag Flapping In The Wind

French scientists have discovered how flags, made of the right material, can be an alternative to wind turbines.

Blowing in the wind
Blowing in the wind
David Larousserie

PARIS — Are traditional bulky turbines the only way to capture the energy blowing in the wind? The answer, my friend, is apparently No.

Earlier this year, a team of scientists from Ecole Polytechnique and Paris Superior National School of Advanced Techniques (Ensta ParisTech) measured how a "simple" flag made of the right material can also be well-suited for the production of energy.

Over the last decade, researchers have been working on the possibility of producing power out of such undulations of a flexible membrane in water, another fluid, or in the air. Piezoelectric ceramics, which create tension when being deformed, are among the most promising materials.

According to the simulations published in Physical Review Applied, the more wind there is the more electricity it creates, though not proportionally because of the erratic undulations of the flag. Where it is interesting, however, is that for the first time, it highlights that the wind is not the only factor in the efficiency of the system; the type of circuit to which it is tied also has great influence. Sébastien Michelin, from l'Ecole Polytechnique, and Olivier Doaré, from Ensta ParisTech explain that "within certain conditions, the productivity can jump from 0.1 to 6%."

Thus engineers are now working on the fabric of flags but also on the composition of circuits. The mechanical and the electrical system are joined together. Thanks to that, even if completely down, a flag would still be able to produce a few electrons. "By influencing the flag dynamics with the electronic components so as to adapt to the wind conditions, we can make it work in many more cases," notes Michelin.

Osenberg

How many flags?

The team is optimistic, noting that making improvements to the electric circuits is not necessarily a complicated task. Christophe Eloy, researcher at Ecole Centrale in Marseille, points out that "they are not the first ones to have the idea to use flags but they are the first to have properly detailed the system."

In reality, these technologies, producing less than 1 watt, will not replace the wind turbines that produce a million times more than the flags. They will, however, be useful for recharging batteries, for example.

Many questions still need to answered; how many flags and in which position? If all of them were in synch, conditions would optimal. Unfortunately, Christophe Eloy and his collaborators showed in 2009 that if three flags were put right next to each other, only two flags would be waving and the one in the middle would stay motionless.

You've reached your limit of free articles.

To read the full story, start your free trial today.

Get unlimited access. Cancel anytime.

Exclusive coverage from the world's top sources, in English for the first time.

Insights from the widest range of perspectives, languages and countries.

Geopolitics

Why Beijing Needs Ukraine To Lose

As the Chinese government puts together what it calls a peace plan for Ukraine, it's also considering sending weapons to Russia. The Biden administration warns China will "pay a real price" if it helps Russia, but Beijing's real goal is to weaken the United States.

Why Beijing Needs Ukraine To Lose
Oleksandr Demchenko

This article was updated on March 21, 2023 at 12:15 PM CST

-Analysis-

KYIV — In Moscow for his visit since the Russian invasion, Chinese President Xi Jinping is presenting himself as possible peacemaker to end the war in Ukraine. Ukrainian President Volodymyr Zelensky has said he is ready to talk with Xi in a bid to stop Beijing from supplying Moscow with weapons.

And yet China has no strategic interest in Ukraine winning the war. Why?

Xi's only priority is establishing a future world order on Beijing's own terms — and the defeat of Ukraine and its allies, particularly the United States, would create an opportunity for Beijing to absorb Taiwan and increase its influence in the Pacific.

Stay up-to-date with the latest on the Russia-Ukraine war, with our exclusive international coverage.

Sign up to our free daily newsletter.

China is the main beneficiary of the full-scale war that Russia has unleashed against Ukraine, viewing the confrontation as a tool to weaken the West.

Like Russian President Vladimir Putin, Chinese authorities were convinced that Russian troops could capture Kyiv in three days and take control of most of Ukraine within a month. This is probably what Putin and Xi agreed when they met during the Beijing Olympics in Feb. 2022: the Russian leader promised to destroy Ukraine, weakening Europe and eroding the trust other democratic states had in the United States — and in exchange, the Chinese leader assured Putin that he would back Moscow.

Instead, what was hailed as "No. 2 army of the world" was forced to retreat. On Sept. 15, as Ukrainian forces were liberating the Kharkiv region, Putin met Xi in Samarkand, Uzbekistan. After returning to Moscow, Putin announced a partial mobilization.

Keep reading...Show less

You've reached your limit of free articles.

To read the full story, start your free trial today.

Get unlimited access. Cancel anytime.

Exclusive coverage from the world's top sources, in English for the first time.

Insights from the widest range of perspectives, languages and countries.

The latest