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Tuesday, July 31, 2007

Levitating in the wind

Could gigantic maglev wind turbines be the answer to the world's energy problems? It's a cool idea, but somehow I doubt it.

Still, that's what an Arizona-based company called Maglev Wind Turbine Technologies is proposing. It wants to build enormous vertical axis turbines that would use magnetic levitation to reduce friction.

On paper, the idea seems to have some merit. After all, a group of Chinese scientists did demonstrate a "maglev" wind turbine at the 2007 Wind Power Asia Exhibition in Beijing. Instead of ball-bearings it has magnetically levitated components. Scientists from Guangzhou Energy Research Institute and Guangzhou Zhongke Hengyuan Energy Science & Technology say it was up to 20% more efficient than a normal turbine and can also utilise wind speeds as low as 1.5 metres per second.

Vertical-axis wind turbines also have advantages. The main benefit is that the turbine does not have to face into the wind and that the generator and gearbox can be placed on the ground. A company called Vertaxwind is even working on designs for very large off-shore vertical-axis turbines.

So far, so good. But Gordon Edge at the British Wind Energy Association thinks giant maglev turbines could be pretty difficult to build.

"My understanding is that [maglev] only works for very small turbines," he told me. "It's not something that's being investigated for large machines. You're talking about levitating a rotor of tens of tonnes which is going to require some very big magnetic fields."

I guess we shouldn't write the idea off completely, but I'll reserve judgement before declaring the world's energy problems solved just yet.

Will Knight, online technology editor.

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Why do they have to be huge and heavy? Can't light weight small units be networked?
By Anonymous Anonymous on August 01, 2007 6:11 PM  
The basic design of this turbine is so inefficient that the type of bearing used is irrelevant! I think the chap from BWEA was being very polite. Reading the Maglev WTT website there is a lot of basic aerodynamics that the proposer doesn't understand. If he believes modern turbines have the same efficiency as old Dutch-style windmills then he's got a lot to learn. (One is a drag device and the other is a lift device.) And there have been ships built, powered by wind turbines, contrary to his website. For a turbine of the size he's proposing my best guess would be for steel wheel/rail bearings, much like railway bogies, running under the rim of the rotor.
By Anonymous Anonymous on August 02, 2007 2:10 PM  
Forget wind turbines and other horrible structures, just build nuclear plants, they are clean, safe and quiet!
By Anonymous peter byers on August 03, 2007 1:16 AM  
Safe in the hands of the competent.
Just keep shoddy Russian safety policy out of the question
It may be an inefficient design...or it may be not. That is not the point - we should be willing to investigate its potential. The luddites who stick to the mantra of "nuclear power" are doing a disservice to future generations by not supporting research into new energy generation technologies.
By Anonymous Anonymous on August 03, 2007 9:51 AM  
Magnetic bearings supporting hundreds of tons may be too expensive and difficult, but AIR BEARINGS would easily deal with these problems, and would make the concept quick and easy to trial as well. Using simple technology which is quite good enough for the problem at hand, will also prevent losing focus on peripheral issues which just detract from proving the main concept.
By Anonymous Anonymous on August 03, 2007 10:31 AM  
The problem with air bearings is they require close tolerances and fairly constant loading. This size wind turbine will have widely varying loads (overturning and horizontal) as the wind speed rises and falls, so the maintenance of the air gap would be extremely difficult.
By Anonymous Anonymous on August 03, 2007 2:04 PM  
I'm not so sure that air-bearings HAVE to be "close tolerance" and can't handle fluctuating loads. Think of a hover-craft or any other air-cushion vehicle. These are nothing more than a type of air bearing, and they very successfully handle exactly this sort of problem.
By Anonymous Anonymous on August 04, 2007 10:28 AM  
wouldnt you need to use electricty to make it magnetic? thereby defeating the whole purpose of the wind turbine.
By Anonymous Anonymous on August 12, 2007 10:00 AM  
Rare earth magnets are those super strong magnets that don't require any energy to be magnetic, so no, it wouldn't need power from my understanding.

It might be really hard to pull off on a massive scale though, I agree with the article, but it might be possible. I hope it is!
By Anonymous Anonymous on November 26, 2007 11:06 PM  
"Rare earth magnets are those super strong magnets that don't require any energy to be magnetic"

Any idea how magnets are made? They use big electromagnets to magnetize the shaped material. They also have to heat the material they are magnetizing above it's Curie temperature, so ovens are involved, too. Overall, it takes considerably more energy to create those magnets than can be extracted from them.
By Anonymous Anonymous on November 27, 2007 2:32 AM  
A permanent magnet provides a magnetic field; no energy is extracted from this field. The notion that it would take more energy to make the magnet than can be extracted makes no sense. These magnets are strong, they provide fields greater than 1 Tesla, but they are expensive.yf
You can talk ALL you want to .
I have BUILT AND AM GENERATING POWER w/ a MAGNETIALLY LEVITATED WINDMILL,IT'S KINDA SMALL ,4FT.ROUND AND 4FT. TALL .IT WORKS WELL.It stats to turn app. 2mph. just a slight breeze,but due to lack of FUNDS it starts to charge the batterys around 10-15mph.
By Anonymous Anonymous on June 13, 2008 10:22 PM  
The efficiency is
wind power (W/m2) /
power produced(W/frontal area)

while it is true that the 3 blade technically has a higher efficiency per area, it is obviously a retarded design economically compared to this one, since this will get about 10 times the frontal area per windmill thus about 10 times the Watts per dollar investment, despite the lower "efficiency".

this so called(read: complete bs!) efficiency argument is to make sure that windmills never become able to undercut coal for energy prices by making them super badly designed. Same argument used on electric cars while over 90% people drive less than 10miles a day. MORE BS!!

If you still don't believe that the elite have crushed all the more practical competitors to oil gas and coal you are living in a happy dream world.
A direct replacement for fossil fuels will "ruin" our economy...time for this attitude to be shot down before it kills us. Besides the only "reason" windmills have only three blades is so the don't break in high wind...NOT FOR EFFICIENCY
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By Anonymous Anonymous on January 11, 2009 4:49 AM