Gipe on Kites and Other Questionable Inventions
Note: This is a response to a post that challenged my critical comments about Makani. The post explained that the performance of the small rotors on Makani was due to their crosswind operation. Thus, they used much higher wind speed than that of the wind across the ground.
Thanks for your message on Makani and thanks for your explanation how they get such high capacities out of those small rotors.
First, let me get the qualifiers out of the way. I am, have been, and will be a big fan of kites. I flew them as recently as a decade ago. And, as the founder of the Tehachapi Wind Fair, I always made sure that kites, kite flyers, and kite vendors were always represented. We also included sail-powered vehicles when we could. I lived and breathe wind energy–and that includes kites.
However, I am an advocate of the rapid development of massive amounts of renewable energy. I don’t see kites in that anytime soon.
I don’t see small wind in that either. I am roundly criticized by the small wind fraternity for this position. Some accuse me of betrayal because I write about, have sold, and have installed small wind turbines.
Having the kite community take exception to me and what I write is nothing new. They can join a long line of critics, including promoters of TARPs, DAWTs, and VAWTs of various stripes.
Sure small wind has an important place, but it will not power the energiewende. It has a niche and we need good turbines to serve that niche. I am still interested in small wind, but I don’t proclaim it as a panacea.
Kites could also serve a useful niche—someday. They’re not there now, and as far as I can tell there are no commercial products. There’s a lot of hype. But hype doesn’t make electricity.
I am afraid published results in scientific journals is not the same as Dr. Gasch’s or my own. Kite purveyors may have published technical papers on their inventions and products. That’s all well and good. I remember reading a lot of published papers and even on occasion peer-reviewed papers by the then leaders in the aerospace community of wind turbines of the 1970s and early 1980s. I’ve just reviewed a few those old papers in the past few weeks. My impression of their results, not surprisingly, has remained the same after three decades. I was doubtful then, and “facts-on-the-ground” confirmed my skepticism shortly after these wondrous new inventions were installed.
What we in the wind industry are interested in are standardized results by a certified testing laboratory. These are performance tests to the IEC standard. For now, I am not interested in the durability tests, only the performance tests.
I didn’t find these on the Makani web site. If I missed them, please send them along.
Until these tests are performed and the results published, it’s all just hype. I say that about all wind turbines whether they are kites or not.
Typically, I write about the performance in the field, that is in kWh generated per year. So, for me, performance tests to IEC 6400-12 are just the first step. I want to see data on actual kWh generated over a certain time period. As far as I can tell, kite promoters are a long way from providing that kind of data.
As to the height at which Makani flies, I believe I got that off their web site. If they’ve changed that, I’ll make the correction.
As to my link to Mike Barnard’s web site, he’s certainly earned my respect during the past few years he’s been writing about wind energy. I frequently feel forced to debunk various wind inventions and their promoters even though I don’t want to spend the time doing so. Thus, I feel qualified to judge the work of others when they take on the thankless job of debunking the latest energy craze, whether it’s shale oil or a new windmill invention.
Barnard’s evisceration of kites as potential wind energy converters is calm, reasoned, and sophisticated. His critique is far more detailed than I think kites—or Aerial Wind Energy Systems—warrant. Still, he did a superb job. If he made mistakes of fact, I am sure he will correct it. He is far more willing to engage his critics in substantive discussion than I with my critics. (This message is the exception.) My hats off to him for being so patient.
To summarize, thank you again for calmly explaining how Makani gets such high capacities out of such very small rotors. And if you find performance reports to IEC 6400-12, please send them along. Better yet, if you find reports showing Aerial Wind Energy Systems are generating useable amounts of electricity, please send me the data or point me to it, because that’s what I really want to see—results.
Airborne wind energy: a collection of challenging compromises by Mike Barnard
Makani Kite Turbines Response by Paul Gipe