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Kite Power: The Latest In Green Technology (thebulletin.org)
New submitter Dan Drollette writes: The solution to producing energy without contributing to global warming may be to go fly a kite. Literally. Researchers in Switzerland and Italy — high-altitude places where the winds are strong, steady and predictable — have been working on ways to generate electricity from kites that fly hundreds or thousands of meters high. The scientists already have a prototype cranking out 27 megawatts; they expect to have a 100-megawatt plant big enough to power 86,000 households. And they say that they can produce electricity for less that 4 cents per kilowatt-hour, which is better than fossil fuel. Plus, the kites look really cool (as does the "Darrieus rotor vertical axis wind turbine" at the base of the St Bernard Pass, on the Swiss side, which I've seen in operation in person).
I think they forgot to google for the technology first: https://www.google.com/makani/
What happens if the wind stops?
The utility plant operators have to compensate by running backwards and pulling harder on the string.
27Mw is no small prototype, but there seems to be nothing about it anywhere.
Depends on the size and scale of the project.
"US army blimp wreaks havoc after breaking free from military facility" (2015/oct/28)
http://www.theguardian.com/us-...
"... dragging its 10,000 foot long cable behind it and knocking out power to thousands."
Domestic spying is now "Benign Information Gathering"
This has been around a while; kites, windbelts, and laddermills were my area to cover for presentations when taking classes on sustainable energy in 2010, and they were a lot of fun. Anything that gives you an excuse to play footage of the Tacoma Narrows Bridge collapsing and demonstrating the awesome power of wind is pretty cool.
Kites hold a lot of promise; they're far safer for wildlife than any turbine, even the large slow ones that don't deserve their bad rap, and they produce up to a third of a turbine's power given similar operating area, for a tiny sliver of the material cost. Solar's cool and all, but wind power has become surprisingly diverse in its options tailored for different environments, and is becoming more so.
The second (and perhaps less researched) approach is to minimize power utilization . It finally has to be a balance between clean power generation and efficient utilization .
Up until a year ago I was doing research in this field. Google/Makani is by far the closest to commercialization at utility scale. They are already on their 8th prototype, a 600 kW version. Nothing public is operating anything airborne in the Megawatts yet.
I can see a lot of fun with aeronautical obstacle databases if this takes off in a big way. Essentially a power plant will need an airspace allocation up to 10000 feet AGL and a nautical mile or two across. Put a lot of these around a city and there are many aeronautical procedure designers that will certainly be cursing as they try to thread an aircraft safely between them.
Patent litigation: A doctrine of Mutually Assured Destruction... in which everyone seems willing to push the button
Actually, even more noisy and higher pitched. The Makani turbines are quite small but the kite is going very fast, so plenty of power, but the result being that the turbine are spinning like crazy.
The more people I meet, the better I like my dog.
1) I've stood directly underneath a 1MW turbine in the middle of a large wind farm on a windy day. There wasn't much noise at all, just a light whoosh... whoosh... whoosh.... I don't know where this concept that wind turbines are "terribly noisy" comes from, but it doesn't at all match my experience.
2) You're concerned with noise about something that's hundreds of meters up? What about kite-based systems that operate at thousands of meters up, would you be worried about noise from them too?
He's the sort of person who would sell the Red Cross to Dracula.
That's part of the reason that blimps are increasingly going out of favor, in favor of hybrid airships. Hybrids are based on the concept of being aircraft (generally lifting-body aircraft) that get huge lifting areas via inflation (so that they don't need any real structural strength, and thus keep the mass very low), and use helium as the inflation gas, which partially (but not completely) lifts the craft. So you have the combination of huge lifting area and much of your weight compensated for, so it takes little energy to stay aloft (which can, for example, come from solar), and unpowered landings are perfectly safe. But because (for the same payload capacity) you don't need as big of a gas bag as with a blimp, they're not as vulnerable to crosswinds and thus not as likely to break free, as well as being much easier to land without being blown into power lines or whatnot.
He's the sort of person who would sell the Red Cross to Dracula.
The global wind resource is 72TW. You're going to have a hard time denting that. You might alter things locally - might - but not globally.
And besides that... if any evil greedy megacorp wants to move into my valley and setup something that will rob the wind of its energy... Please Do! Seriously, someone should really work on wind turbines specifically designed to act as windbreaks, in a manner that can be affordably mass produced and deployed in lieu of traditional manufactured windbreak systems.
(Before anyone says "just plant some trees..." I do, every year. They usually get killed by the weather, sometimes outright uprooted. I may have to start spending more time on each tree individually, encasing each one in its own individual PVC windbreak in addition to the broad rows of pallet windbreaks)
He's the sort of person who would sell the Red Cross to Dracula.
If I remember this company's tech correctly, the wind drags it out, turning a generator as it goes. They then switch it to a low-drag mode and reel it back in. So it cycles between high power generation and low power consumption. The concept being that you'd have many of them so that you'd get continuous net generation.
He's the sort of person who would sell the Red Cross to Dracula.
Having read the article, I'm entirely convinced this is not scalable; we're not going to power cities with this. I'm not convinced it is not useful in some places at some times; small remote towns that don't have anything else would find it cheap and useful. It is clever. Assuming the wind blows [way up yonder] with great consistency, this has a lot of promise. My gut tells me you'll need to fly at least three to make it close to distributable; Like juggling. Obviously the more that are flying, the more consistent the result will be (as long as the wind keeps blowing). My gut is often wrong. Can any of you smart guys model this?
If I remember this company's tech correctly, the wind drags it out, turning a generator as it goes. They then switch it to a low-drag mode and reel it back in. So it cycles between high power generation and low power consumption. The concept being that you'd have many of them so that you'd get continuous net generation.
Slow and powerful drag out is going to have a massive, complicated, and hard to maintain gear box to run a generator. Generators run at hundreds of RPM. This is the same problem with big wind turbines, making power into RPM in a gear box is hard. If you have a wind farm around, look at the ones that are stopped they'll have black stains on them where the gear box failed.
On a tower, they are difficult to service.
On a floating, bobbing, need to use a boat to get to, they are probably going to have to un-hook them and bring them to shore to fix.
Those kite things are overly optimistic given the state of the gearbox technology used today.
We increased forcing from CO2 50%. The power didn't come from our putting energy into the system, it came from stopping the sunlight leaving so quick. Hence your comparison is ridiculous and moronic.
But it was the "best" you had, so you went with it.
Since the anti-environmental types tend to be the pro-capitalism types, I ask the parent post writer to look at it this way: the biggest expense for a fossil fuel power generation plant is the fuel itself. So they have the best reason in the world to pursue maximum efficiency: profitability.
So unless someone presents credible evidence the fossil fuel power industry has been intentionally wasting billions of their own dollars, we have to assume modern energy plant efficiency is pretty close to optimal for the technology being used.