How many could one fit in a given area?
Assuming one per a box 500m*500m, that's 400 in a 10km square. At 10MW each, that's 4GW. Of course one would need a no fly zone around it. I essentially pulled these numbers out of my ass; anyone have beter ones?
The other issue I haven't been able to figure is tether strain. Wiki's talk page has it as the power generation/windspeed, is this right?
Flying Wind Turbines
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OneWayTraffic
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Actually I was using P=F.v (notation is lacking, but this is the vector dot product) and simplifying to scalar.MSimon wrote:F=ma. So how much mass do you have to decelerate to get the required energy?
Then if you have the rated power claim and the average wind speed is 90km per hour (25m/s) then you'll need at least 40kN per MW. Is this correct? If so then with 3000Mpa materials it shouldn't be an issue.
I don't think it has any chance of working on a commercial scale. There's just too much to go wrong sitting way up in the air 24/7, with a tether reaching all the way down. It's an overly dynamic and uncontrolled environment.If it works this could be as big as polywell for terrestial use.
I don't even want to think about maintenance, and coordinating landing/take-off with those cables.
Plus, there's the NIMBY problem. Obviously you can't put these anywhere near a metro area, which means they'll be far away from high-demand areas.
I'm not saying you can't generate power this way, I just don't see it being competitive economically.
Forest Fires
IIRC, they were incindiary bombs intended to set fire to the forests in the northwest. They reasoned we would have to divert manpower to fight the fires, as well as denying timber resources to our industry. As you noted, it didn't turn out to be overly successful.TallDave wrote:Most people don't realize the Japanese bombed Idaho.
They attached bombs to balloons and sent them over to fall at random, but we barely noticed. They didn't really grasp how big and empty the United States is compared to their own country.
Be Safe
Mumbles
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StevePoling
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Japanese bombed Michigan, too
The Japanese bombed Michigan. One landed about 15 miles southwest of where I live near Grand Rapids. I think another was spotted (but not found) heading toward Canada over Lake Huron, but I could be mistaken.TallDave wrote:Most people don't realize the Japanese bombed Idaho.I believe barrage balloons were used extensively in WW2.
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ravingdave
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Re: Forest Fires
Mumbles wrote:IIRC, they were incindiary bombs intended to set fire to the forests in the northwest. They reasoned we would have to divert manpower to fight the fires, as well as denying timber resources to our industry. As you noted, it didn't turn out to be overly successful.TallDave wrote:Most people don't realize the Japanese bombed Idaho.
They attached bombs to balloons and sent them over to fall at random, but we barely noticed. They didn't really grasp how big and empty the United States is compared to their own country.
Be Safe
Mumbles
It is my understanding that one of these ballon bombs did manage to land and start a fire in the northwest. It WAS a massive blaze and it DID require a huge amount of manpower and resources to suppress it. The US Government immediately declared a news blackout on the fire to prevent the Japanese from finding out how successful the idea was. The Japanese, hearing no mention of it in US media concluded that the project wasn't working and so they stopped.
David
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OneWayTraffic
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I could no more do that than build a device that could trap electrons in a magnetic bottle, inject high energy ions and capture the resulting fusion products while simultaneously keeping the superconducting magnets making it all possible at 40k or less.MSimon wrote:Jet streams run at 10 to 15 km altitude. Let us say 10 km.
Are you going to tell me that you can keep a 10 km long tether coordinated with another one .5 km away? Seems iffy. I think 2 to 5 km is more like it.
I think that the machines themselves could be controlled quite closely given GPS and computer control. It works for airplanes pretty well. The tether OTOH is a giant unpowered dragline.
Reading between the lines here, it seems that the company is making claims that they'll be able to pack them a lot closer. Lets say they'll wrong and we'll start conservative at 5km seperation. The physical limits would quickly be found out in operation, as one gathers hard data on how well the devices are controlled. Occasional tangles and collisions would be expected in commerical operation as it's a question of economics not safety. i.e. the optimum level of mishaps may not be zero.
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OneWayTraffic
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That's the biggest problem as far as I can see it. But we (sceptics) have said the same about lots of technological marvels that simply became reality as soon as there was a reason to do it.TallDave wrote:I don't think it has any chance of working on a commercial scale. There's just too much to go wrong sitting way up in the air 24/7, with a tether reaching all the way down. It's an overly dynamic and uncontrolled environment.If it works this could be as big as polywell for terrestial use.
Landing/take-off shouldn't be an issue. If current energy trends continue noone will be flying. Besides that the amount of airspace in the world is massive compared to that used by planes. If it works, and if it's economic enough to meet the most optimistic predictions then the airspace will be a very small tradeoff for energy independence and greatly improved balance of trade. If it doesn't work or works in a marginal way, then it will take up a 0-very small amount of restricted airspace.
I don't even want to think about maintenance, and coordinating landing/take-off with those cables.
Do you see the NIMBY problem being any more than that for coal fired plants, nuclear plants or current wind turbines? I would say that it's probably less of an issue.
Plus, there's the NIMBY problem. Obviously you can't put these anywhere near a metro area, which means they'll be far away from high-demand areas.
Most companies/scientists working on high energy wind are predicting 1-2 cents per KWh. Of course most sources of funding are a lot more sceptical. Though if the calculations are honest, 1 cent per KWh leaves a lot of room for Murphy's law.
I'm not saying you can't generate power this way, I just don't see it being competitive economically.
I'm not sure that the idea will work out myself, but one could fund all of the fringe wind ideas out there with less money than the US spends on oil every hour. At that level of financial risk, surely it's worth some investigation? I say the same about Polywell; it's just not that risky to try it. It seems most of the posts here have mentioned various engineering problems, but there's been no fundamental physical laws broken by this concept. So "it may never be economic, but it's great science." Worth a try.
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OneWayTraffic
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Re: Forest Fires
And I read that one of them severed a powerline to the Manhattan project, putting it back a bit. Maybe an urban myth?ravingdave wrote:Mumbles wrote:IIRC, they were incindiary bombs intended to set fire to the forests in the northwest. They reasoned we would have to divert manpower to fight the fires, as well as denying timber resources to our industry. As you noted, it didn't turn out to be overly successful.TallDave wrote:Most people don't realize the Japanese bombed Idaho.
They attached bombs to balloons and sent them over to fall at random, but we barely noticed. They didn't really grasp how big and empty the United States is compared to their own country.
Be Safe
Mumbles
It is my understanding that one of these ballon bombs did manage to land and start a fire in the northwest. It WAS a massive blaze and it DID require a huge amount of manpower and resources to suppress it. The US Government immediately declared a news blackout on the fire to prevent the Japanese from finding out how successful the idea was. The Japanese, hearing no mention of it in US media concluded that the project wasn't working and so they stopped.
David