Indeed! And it's real. We can do it now. We don't need to develop completely new technologies. We know how to do it. It is just an engineering problem.
I am guessing you may be a bit behind on the times and may be unfamiliar with Space X. https://singularityhub.com/2018/12/...-from-space/#sm.0001aixn65nzney6znk1guo64p71n
I went back and checked the previous posts and didn't see a link. Can you give me a link to "off the shelf" generators that produce 500 KV and would be suitable for this idea?
There are very few places on the tops of 10,000' mountains that you can launch something half the size of a 747 which means that now you need to use your alternative which would be the sea option. Perhaps a couple of off shore drilling rigs could be joined together to create a large enough platform for a single one of them. You will also need an undersea cable capable of carrying high voltage. That could be a serious challenge all by itself since it would have to be at least twice the length, if not three times in order to ensure that your FEG's are far enough off shore not to crash onto land. This also raises the question of how safe are high voltage undersea cables? How much induced loss would occur from the salt water itself? Would this have an impact on marine life in the area? Then again it might just make more sense to base them on the shoreline where the jet stream is blowing off shore. That way your cables remain on land while the FEG's are flying over the sea. If there is a failure then it will be blown away from the shore. This might even work on the shores of the Great Lakes. Not certain how much that kind of beachfront property costs either but it would solve a lot of your safety issues. In addition a number or nuclear plants already exist on shorelines so they could be repurposed given that they already have all of the grid connections in place.
The design of wind turbine blades is fascinating. Ground based turbines use large blades because they need a lot of pressure at low air speeds. in addition they need to be able to stall when the wind speed increases so as not to burn out their bearings by going too fast. Your challenge is quite different in that you have very high wind speeds all the time and therefore much higher air pressure driving them. You would actually want smaller blades and more of them to achieve the generation capacity. Perhaps the most important factor to be concerned with is the sound barrier because if your blades exceed that speed it will result in all kinds of problems like vibration and loss of control. Figuring out the stall speed of the blade is going to be crucial.
Concerning the "high pressure" in the jet stream: https://www.sciencedaily.com/releases/2011/11/111130100013.htm
Sorry for going off-topic, but... The general acceptance of phrases such as: "200 times less", bugs the snot out of me. There is a big difference between 0.005 and -199. If they mean 0.005 times they should say: ' one two-hundredths. Two hundred times less equals negative one-hundred and ninety-nine times the original value. That is all.
Heehee... I am still waiting on input from the OP on these cheap, lightweight, high voltage, high power generators that are sitting on the shelves ready to be purchased.
You added to your message after I replied. I understand your point. I suppose that the person who wrote the article about the data from the Planck Institute was dumbing it down for the general public. Still, what I think they mean can be pointed out by this hypothetical: Someone claims that the wind in the jet stream can produce 4,000 times more power through a turbine than a wind at ground level can. Scientists do a study and find that it is only 20 times as much. This is "200 times less" than what was claimed. The claimed factor of 4,000 was actually only a factor of 20.
Flying electric generators are a very interesting concept. Any feasible engineering challenge looks like a walk in the park compared to space elevators though. They're essentially impossible to build (on earth). As far as I can tell, 500kV generators aren't generally in use. Such a high voltage is not the most economical and reliable choice. Insulation at such high voltages, while keeping the total volume of the winding small, tends to be an issue. Staying below about 30kV appears to be the better compromise between voltage and current. In this case, high voltage DC might be an option. DC power conversion using semiconductors would also allow the use of an exotic generator operating at an arbitrary or even variable frequency at no extra cost. https://new.abb.com/systems/hvdc/hvdc-light I'm not sure whether it's better to have the conductors on the inside or outside of the tether. Having the current flow inside the tether, makes the tether less bulky, but makes proper and reliable insulation a real challenge. It might be better to have the conductors on the outside. That way, corona discharge won't eat away the mechanically relevant parts of the tether. With a two conductor solution, you would have to keep the conductors separated though, increasing complexity and making the whole thing look more like a rope ladder. The tether looks like the most exotic component to me. Producing a lightweight tether of about 10km length that can transmit power and deal with both the static and dynamic forces in all imaginable situations won't be easy.
No, that's not what they're saying. They are talking about the total power output of all wind turbines put into jet streams. Putting generators into the jet stream produces drag and slows it down. They claim that when about 7.5 TW of power is extracted from the jet streams, the winds begin to flow in significantly different patterns. As a comparison, the total output of all nuclear power plants on earth accounts for about 0.4 TW. Extracting that amount of power from the jet streams would probably still work out. Making aerial wind turbines our sole source of power is both unrealistic and foolish anyway. It might be a viable power source in some locations though, if enough engineering effort is put into it. The scaling law presented in the opening post is about right in my humble opinion. I can think of only one large effect HereWeGoAgain didn't take into account. The air density at jet stream altitudes is only about one third of the density at ground level. This reduces the power output by a factor of 3 for a wind turbine of a given effective area.
Ack! I didn't consider density. So there is a trade off between wind velocity and altitude. Apparently one can normally access the jet stream at about 20,000 feet. So lower is better when possible.
I have actually seen 500 KV generators - very big ones. I ran across them about ten or twelve years ago when I first started investigating this energy option [got sucked into algae instead ]. And transmission lines now use up to 500 KV. So they are being powered by something. Maybe a generator and transformer makes sense here as well. Beyond that, you can run the generators in series to achieve 1 million volts or the highest voltage possible. But no matter what is selected, it would have to be a custom design. I don't think any very large generators are designed to minimize weight. Clearly weight is a major constraint here.
To me the key is that FEGs, while challenging, are a very earthly solution. A space elevator is still in the science fiction arena. People often get lost in the difference between something that is possible, and something that will or might one day be possible.
FYI, I have actually taken about a 500,000 volt shock. But that came from a Tesla Coil - plus or minus a quarter-million to each hand. I instinctively want to drive towards DC. But the advantage in going to high frequency is certainly worthy of consideration. Higher frequencies allow for lower voltages, for the same power.
Hah, saved by scope drift. I started talking about a 1GW FEG, which is on par with a typical nuclear reactor. But the original calculation was So based on the 6400 sq meters for the total swept area, we would still expect an average of 2.1 GW, which is about half of what the three reactors at Palo Verde can produce. Obviously this is all somewhat arbitrary as an example but it provides a sense of scale.
I'm also thinking that making the tether control intelligent and responsive, responding to sensors on the FEG, could solve many problems. Say for example the wing hits a large air pocket and drops rapidly. Accelerameters on the FEG, communicating live data to the tether system, allows for the system to respond to changes faster than the mechanical effects reach the tether control. It might even be used to help cancel resonances that occur in the tether. Obviously it would use elevators, rudders, and stabilizers, just like a plane, and all computer controlled. These should in principle provide control much as you have in a commercial jet.
My explanation to Thought Criminal concerned the semantics of "200 times less" and was an off-topic sidebar. I can accept your version of the article though.
