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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).
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.
Less researched?
It's the road most followed.
Even traffic lights have LEDs in them now. People who did not care about building insulation at all a few years ago have it. Roofs are being painted white. We could always do more but it is definitely not being ignored.
Most other countries have continously falling birth rates, even the so called poor ones. The average birth rate in the African countries for instance is close to 2.5 children per woman, not much higher than for instance the U.S..
Makani uses a completely different approach: They use a wind turbine to generate electric energy and just use a kite to get the turbine to 250m height, while the kites from switzerland are basically passive kites and the aerodynamic lift is used for generation of power. Makani could generate energy contiguously while this SwissKitePower approach would alternate between ascend and retraction phases and only produce power during ascend.
Jan
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.
Even if China isn't exploring new fancy nuclear designs, they currently have 26GW of generation capacity, they are bringing a further 40GW online in the immediate future (plants already under construction many of which are nearly finished), and a further 50GW of generation capacity is already planned beyond that. That's a bigger push for CO2 free energy than a lot of other countries are currently making.
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.