Turbine Taps
Stronger Winds


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Turbine Taps Stronger Winds - Turbines

Altaeros Energies has launched a turbine in a blimp using cheap, existing technology. Image: Altaeros Energies

The tallest wind turbines in the world do their turning in the 440-foot range. The current record holder, in Laasow Germany, tickles the air at 525 feet.

But the real juice is found at twice that altitude.

The air that circles the globe above 1,000 feet is faster and more constant than what's found closer to the ground. The question is how to get it. Conventional turbine-on-tower technology is not economically feasible at those heights. "I don't think that there's a material in the world that could produce a cost-effective tower that tall," says Ben Glass, founder and CEO of Altaeros Energies.

So why not get rid of the tower altogether? Send the turbine into more rarified air riding on the inside of a blimp. That was the epiphany that struck Glass several years ago.

Turbine Taps Stronger Winds - Turbines

Aerofoils give the inflatable lift and keep it pointing into the wind. Image: Altaeros Energies

"It was an epiphany that needed a lot of leg work," says Glass. "I tend to come up with a lot of ideas, and I have a core group of very smart people that I run them by. We try to pick a lot of holes in the ideas, and if it can survive that kind of scrutiny then maybe we can go ahead with it."

Went ahead with it they did, and in March, Glass and his compatriots launched a prototype. Though they idea was new, the technology was not—the turbine was an off-the-shelf residential sized affair. Glass did swap out the heavier materials for lighter ones where he could.

Airborne Turbine

The aerostat technology was of the tried and true sort used by weathermen for decades. Glass had one built in the shape of a donut with airfoils. The turbine sits in the donut hole, and the airfoils keep the system more easily aloft and pointing into the wind. "We could see the output increase as it went to higher altitudes," says Glass.

The landing of the aerostat is completely automated—no human need help bring it down in the event of a storm.

The prototype, which topped out at 350 feet, was merely a proof of concept. Future versions will hover somewhere in the 1,000 to 2,000 foot range. At that height, with a single chord connecting it to the ground, it will be a bit hard for aesthetes to knock the turbine as a noisy eyesore on the landscape.

Increased Output

The energy lost thanks to the loss in stability that comes with detachment from the earth is insignificant, says Glass. With the higher, steady winds found at that height, the "airborne wind turbine" as it's known will produce two to five times as much power as a traditional one. That's about 100 kilowatts, enough to power 40-odd homes.

Not bad for a clean energy, but at 20 cents per kilowatt-hour, it's not quite competitive for what you might find on the New York grid. The ultimate goal is to get the price low enough to steal some of that business but until then, Glass has his sights on remote locations where power is more expensive. "Off-grid and remote applications have the highest cost, because they're using energy from diesel gensets," says Glass. "Typically, they don't have an option for cheap or clean energy." The cost is anywhere between 30 cents and $1.50 per kilowatt hour.

"Our goal is to get something on the market that shows it works and is effective and safe," says Glass. "In the long-term, we'll be able to produce offshore wind energy that would be competitive with any type of grid energy."

Michael Abrams is an independent writer.

In the long-term, we'll be able to produce offshore wind energy that would be competitive with any type of grid energy.

Ben Glass, founder and CEO, Altaeros Energies

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August 2012

by Michael Abrams, ASME.org