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Innovations to boost airborne energy have wind at their back

Modern-day Ben Franklins are using kites and other low-altitude flying devices tethered to the ground in high-tech efforts to harness energy that one day may power your home.
Makani Power is developing kite-like airborne wind turbines to extract energy from powerful, consistent winds at altitude.
Makani Power is developing kite-like airborne wind turbines to extract energy from powerful, consistent winds at altitude.Photo courtesy Makani Power
/ Source: contributor

Kites and blimps may be the next big thing in wind energy and may even power your home one day – and we’re not talking decades from now. Think years.

Why? The higher you go up, the stronger and the steadier the wind and the more energy you can grab. Scientists say that a wind turbine high in the sky could generate 20 times more energy than a traditional model standing 200 feet off the ground.

“The jet streams are like a river of free, clean, and concentrated energy flowing above us, waiting to be tapped into,” says Cristina Archer, a California State University, Chico, assistant professor of environmental sciences who has written research papers on the topic.

That promise has inspired a throng of entrepreneurs and inventors who are now trying to transform what was once stuff of science fiction into real energy businesses. The goal is the same: build mega-watt systems that can wean the world off fossil fuels and grab a slice of the $63 billion global wind energy market. The U.S. Department of Energy expects that wind will provide 20 percent of the nation’s energy by 2030 – up from just 1.8 percent today.

“It seems that every month I get an e-mail about another startup,” says Archer. “They’re popping up left and right.”

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The darling of this nascent airborne wind industry is Makani Power, which landed a $20 million investment from Google and a $3 million grant from the Department of Energy. Makani's engineers built an airborne wind turbine wing that, like a kite tied to the ground, sweeps across the sky at 800 feet. The motion captures wind energy on the wing and transmits it to the ground through an electrically conductive tether.

Google has invested more than $85 million in renewable energy projects and companies, including an investment earlier this month into a 350-mile offshore wind project. "We’re always looking for compelling ideas that make economic sense and will help create a clean energy future," says Google spokesman Parag Chokshi.

“This could potentially be the wind turbine of tomorrow – we don’t know. But it seems promising,” says Arun Majumdar, the Department of Energy’s director of the Advanced Research Projects Agency, which funded Makani. “Their technology was totally different. We found it quite fascinating.”

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A different approach
Other startups take a different approach to mile-high wind. Magenn Power in Mountain View, Calif., is building helium blimps that use fabric sails to capture wind and send energy down cable tethers. Buoyed by $9 million from investors and a $500,000 grant from the Asia-Pacific Partnership, Magenn may be about a year away from marketing the airships.

Just down the highway in California is Joby Energy, a venture started in 2008 by entrepreneur JoeBen Bevirt, who sold his last company to Agilent Technologies. The Santa Cruz company’s 35 employees designed autonomous gliders that carry rotor turbines tied to the ground.

And in Italy, a company called KiteGen uses a pulley system attached to a single kite flying at 2,624 feet to activate alternators below and produce electricity. The company hopes to start selling its airborne power systems sometime next year.

The premise behind airborne energy is not new. In the 1970s, engineer Miles Loyd wrote a paper about how to use an airplane on a piece of string to generate massive amounts of electricity. The idea lost momentum when oil became so cheap.

Concerns over global warming and the energy crisis jump-started the concept again a few years ago. But most early airborne wind inventors still operated under wraps, rarely disclosing designs or plans to anyone. That is, until last year.

“They realized that they would have more benefits by becoming a group than by being secretive,” says Archer, the professor from Cal State. She helped create a trade group called the Airborne Wind Energy Consortium, and the companies began sharing ideas and problems at annual conferences.

The consortium’s second conference last month at Stanford University attracted top scientists from national labs and universities, venture capitalists and a growing number of entrepreneurs.

Technology has improved
“Three or four years ago, there was certainly some skepticism,” says Archan Padmanabhan, director of business development at Joby Energy. That has changed, he says, as technology has improved and inventors have demonstrated that their ideas could work.

Now entrepreneurs and scientists believe airborne wind turbines could be used in offshore wind farms and in 80 percent of the U.S. — including those places with dips and valleys that do not work for traditional wind turbines because of a lack of surface wind.

The lightweight structure of the new contraptions, too, could also mean less expensive and easier installations. And because winds at altitude are steadier and stronger, the devices might generate more power. Makani, for instance, promises that its machines will generate energy at a 40 percent lower cost than conventional wind turbines.

“It’s technically feasible but there are a lot of challenges to get the costs down,” says Bob Thresher, a research fellow at the National Renewable Energy Lab in Golden, Colo. “They have a long way to go.”

Companies must deal with safety issues, says Thresher, such as ensuring heavy electric cable lines don’t get tangled or that birds don’t fly into them. The machines need to handle extreme weather and big wind gusts, and the Federal Aviation Administration must approve the machines so they don't obstruct air traffic.

Makani will use the Department of Energy’s $3 million grant to build its 20-kilowatt prototype and to develop new computer algorithms that let the wind turbine literally flyby itself, even launching and landing autonomously. The computerized sensors would also detect problems while in the air and automatically land the craft.

Makani’s CEO and chief technology officer, Corwin Hardham, says that building the turbines will be expensive, and it will cost millions more to build the full-scale machines needed to prove the concept works – and works reliably over a number of years.

“You’re talking about building an entirely new energy technology,” says Hardham. “It’s technology that has the opportunity to make a big difference in how we live our lives. It’s wonderfully exciting.”