The Makani Airborne Wind Turbine
[ASSURAS] Maybe the answer lies in a new type of turbine, a daring innovation that could turn child's play into a steady source of emissions-free electricity. "energyNOW!"'s Josh Zepps looks at one company leading the charge in wind innovation.
[ZEPPS] If you have any fond childhood memories of flying a kite, then you have a real sense of just how much energy the tug of the wind can have. So, what if that same energy could be used to generate electricity?
[CORWIN HARDHAM] The genesis of the idea actually started with kite surfing.
[ZEPPS] You're a kite surfer?
[HARDHAM] I am a kite surfer, yes.
[ZEPPS] But not just any kite surfer. Corwin Hardham is also a mechanical engineer with a Ph.D. from Stanford. And, by the way, that's really him.
[CORWIN HARDHAM, CEO, MAKANI POWER] When you're a kite surfer, you get a very visceral feel for the force that's able to be created with these very lightweight wings. So your kite weighs about 5 pounds and able to pull about a couple hundred pounds of force in relatively slight winds.
[ZEPPS] Hardham wondered if it's really necessary to build enormous wind turbine towers at a cost of up to 3.5 million bucks apiece if so much power can be captured by nothing more than a kite and a light tether. Well, that's a question that also interested fellow kite-surfing Stanford grads Larry Page and Sergey Brin. You know, the founders of that little Web startup, Google, which put up 20 million bucks to help Corwin Hardham find the answer.
[HARDHAM] The difference between a wind turbine and what we're doing is we actually have a wing that is free-flying and tethered to the ground, almost like a kite. So you have this kite flying very much the same pattern as a tip of a wind turbine blade, but up higher in the sky.
[ZEPPS] Imagine the arc that's traced by the blade of a conventional wind turbine. The idea of the Makani Airborne Wind Turbine is to achieve that same motion without all the scaffolding of the turbine structure itself, which accounts for 90% of a regular wind tower's mass. Instead, just a fleet of light, motorized, self-piloting, fixed-wing gliders, tracing lazy circles in the sky, and sending the electricity they generate back down a cable and into the power grid. Hardham says this would have two big advantages over wind towers.
[HARDHAM] We're using a fraction of the material to capture the same benefit.
[ZEPPS] A conventional 1-megawatt wind turbine can weigh more than 100 tons. Makani says its 1-megawatt airborne turbines weigh 1/10 as much, at an installed price that's about half as costly as a normal turbine with the same rated power.
[HARDHAM] The next advantage we have is we're flying a little bit higher in the sky, so we're at about 1,000 feet up. The wind is about twice as powerful at that altitude.
[ZEPPS] Hardham says Makani's system will generate power twice as consistently as the best wind farms of today.
But what about when the wind doesn't blow? Well, the kites can fly themselves, but they consume electricity if the wind speed drops below about 9 miles an hour. So, when long periods of low wind speeds are expected, the kites would be landed.
Still, the project is a long way from being commercial.
[DAMON VANDER LIND] This rotor right here weighs 300 grams.
[ZEPPS] Damon Vander Lind leads Makani's systems engineering team. The carbon fiber wing was his design.
[LIND] It's very light, so this whole piece right here weighs about 30 pounds. And it breaks at a force of about 4 tons.
[ZEPPS] This 26-foot wing doesn't generate any power. That's just a glider on autopilot, banking endlessly across the sky. What generates the power are the rotors mounted on it, which gobble up the onrushing wind.
[HARDHAM] So, very much like on your electric vehicle where you might step on the brakes to actually generate power, we're doing the same thing here. We're actually stepping on the brakes with these rotors that you see on the wing and slowing the wing down.
[ZEPPS] They're not just any old rotors. They also function as propellers to get the wing up to speed.
[HARDHAM] So using some power from the grid or some standby power, we launch vertically, we hover up off the ground, using the same rotors that we use to generate power. So, in that mode, the rotors are actually operating as propellers. And then, when we start generating power, flying, being pushed by the wind, they operate as turbines.
[ZEPPS] One thing that strikes me, this is surprisingly small, given how huge the wing is.
[LIND] Yeah, this thing is basically like trying to generate in a hurricane, because of the speed of the wing flying.
[ZEPPS] How fast is the wing going?
[LIND] The wing goes about 150 miles an hour.
[ZEPPS] Right. So these little things are going like the clappers.
[LIND] Yeah, they go really fast. And actually, one of the big problems is designing these to be quiet.
[ZEPPS] And that, of course, could be a big problem. Because Makani's rotor blades spin at speeds of over 250 miles an hour, they buzz. [Blades buzzing] Makani says it's making huge strides in reducing the noise. Wind energy opponents say conventional turbines are already too noisy, unsightly, and a collision hazard for birds. At the end of the day, like all green energy technologies, Makani will most likely succeed or fail on the price of the power it generates.
[TEXT ON SCREEN] See how the Makani wind turbine works at energyNOW.com.
[HARDHAM] What we expect the cost to be is around 3 cents a kilowatt hour, which is quite low. That's getting lower than a lot of coal-fired power generation at the moment. And that is the thing that gets us very excited about what we're doing here.
[ZEPPS] So, when people are crossing the Bay Bridge and wonder what that black shape is arcing across the sky, it's not a bird, it's not a plane... it might just be a glimpse of one way we could harvest wind power in the future. In Alameda, California, Josh Zepps, "energyNOW!"
[ASSURAS] Makani won the energy category of this year's Breakthrough Awards run by the magazine Popular Mechanics. Makani says it's developing a bigger turbine that would fly at 1,600 feet and produce enough electricity to power 600 homes a year. It plans to have a prototype ready by 2013 and go into commercial production by 2015.
Flying a kite has often been considered child's play - until now. A group of inventors are working to turn the kite-flying concept into an airborne wind turbine that's lighter and cheaper traditional wind turbines.
Correspondent Josh Zepps meets the innovators who could change wind power forever.
Last Wednesday was a big milestone for people who care about public health and a livable climate. Two utilities announced the planned closure of nine coal plants.Read more ...
Today, in the UK, the world's oldest nuclear power plant shut down.Read more ...
The U.S. led the world in clean energy investment in 2011, but China retained the top spot in the latest Renewable Energy Country Attractiveness Index from Ernst & Young.Read more ...