Flying a kite to produce power may conjure up images of Ben Franklin, who sought to prove lightning was electric. Makani Power releases a turbine blade into the air, seeking to harness wind energy at higher altitudes.
Full story by Matylda Czarnecka here.
At any one time there are at least three of us wearing Makani gear; we never considered this remarkable. When photographer Phil Toledano arrived for a photo shoot and eschewed the specially shipped button-ups in favor of our company hoodies, we realized we were on to something. A few months later, we’re pleased to report that you, too, can slip into something a little more comfortable—super comfortable—and you can find it here.
First, wing mounted generators allow the Makani AWT to generate power continuously in a repeated circular flight pattern. Comparably, ground based, winched kite systems must consume power and change flight controls during a retract phase at the end of each cycle. Second, the onboard generators can be used to provide thrust to hover the wing in a manner similar to a helicopter, allowing launch and retrieval of the wing from a small platform. Third, If the wind speed drops or changes directions quickly, the ability to easily and quickly create thrust can be used to keep the wing airborne and under precise control. Finally, wing mounted rotors spin at high speeds, allowing them to drive small, efficient, high RPM generators without a gearbox.
The Makani Airborne Wind Turbine (AWT) is designed to be reliable and robust over a wide range of conditions. While the wind at altitude is typically more consistent, large scale variations in speed and direction do occur. Wind speed variations do not significantly affect the trajectory of the wing, since they are small in comparison to the speed of the wing.
On the other end of the spectrum, the Makani AWT has been shown in simulation to operate in hurricane conditions: winds in excess of 50 m/s (112 mph) with gusts reaching 80 m/s (179 mph). Unlike a conventional turbine, which must actively pitch its massive blades with servo drives to compensate for gusts, the Makani planform pitches into the gusts passively, reducing loads quickly.
We are starting a project to document pages from the notebooks of our team, inspired in part by our appreciation for the kite research notes from Alexander Graham Bell’s files in the Library of Congress. Our first pages are from the notebook of Dr. Paula Echeverri, a member of the systems team.
Our Chief Engineer, Damon Vander Lind, purchased a copy of Newpan to review this quarter. Newpan is an advanced 3D panel method software for the computation of external aerodynamic and hydrodynamic problems. It is used in the aerospace, automotive and marine industries. Previously, we used software such as Xfoil to design and analyze 2D airfoils. Damon used Newpan to analyze 2D airfoils, perform inverse design on 2D airfoils, and analyze 3D wings.
After working with the software for three months, Damon has concluded that the design process with NEWPAN is faster than that with fully coupled Navier-Stokes simulations, but comes at the cost of a greater dependence of results on manual gridding and reduced accuracy for non-lifting surfaces, such as the fuselage and tail boom. Many aspects of the code are highly accurate and useful for the generation of good aerodynamic designs. It is especially powerful when it comes to design iteration as it allows inverse designs on 3D configurations. However, the viscous modeling still requires careful checking on a case by case basis, and gridding is time consuming.
The Makani book club read Powering the Dream by Alexis Madrigal this quarter. The book put the renewable energy field into historical context and gave us a fascinating look at older technologies, highlighting lessons from the past for modern-day renewable innovators. Andrea’s review follows.
With recent insolvency and setbacks headlining in the renewable energy sector, and nations questioning whether their carbon emission targets are possible in the current economy, it seems like an especially hard time to be green. Putting recent events into perspective and pointing the way for ambitious and altruistic renewable energy capitalists, Powering the Dream gives us a history lesson that reminds us that we’ve been here before.
If you believe, as we do, that humanity must find sources of power that do not require burning stuff, more interesting than early wave power experiments or electric streetcars (though they are still intriguing) was the path Madrigal sketched out from the mess of policy and the morass of public opinion to an anthropogenic future of energy production balanced with nature.
Despite our present economic woes, because of breakthroughs in materials science and information technology, the time to develop ambitious technological projects really is now. Madrigal writes,
“It may be the wind and sun’s very imperviousness to human control and denaturing that has made them little-used energy sources. They do not fit into the modern project. At best, they will be a half-tamed naturalized power source. But information technology may be able to flip that disadvantage into a powerful positive. Understanding how to use the wind (without controlling it) may both improve power production from renewable energy flows and also provide a new model for how we can live in our human reconstructed world without destroying it.” [emphasis added]
Powering the Dream posits that new renewable energy projects, far from being a drag on the economy, show us a way out from the rock we’ve pushed ourselves under. Definitely worth a read.
A photo of Andrea’s real copy of the book, demonstrating what happens when you carry a book everywhere for a month, in your bike bag, with your coffee.
Energy Now, a weekly TV news magazine based in Washington DC, came out to speak with Corwin and check out our turbine. The show they produced was an hour long look at the future of wind power. You can watch the entire story or just the section on Makani on their website.
Makani Power was featured on PBS NewsHour December 5, 2011. The story is a pared-down version of the one that first aired on QUEST, a show that highlights science and technology in the Bay Area. You can watch it here.
A power plant that flies itself… we appeared on Gizmodo today. “No matter how tall a traditional wind turbine is built it can’t reach the stronger, steadier winds that blow a quarter mile above the ground. That’s why Makani Power traded the turbine’s tower for a tether and created the Wing 7 aeronautic power plant.”
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