I recently saw a row of power lines with small boxes attached to the wires at the poles. I think these are step-up and step-down generators. Their purpose is to increase the energy or decrease the energy going through the wires so the appropriate amount of energy is traveling through the wires. Regardless, my question is: Why can’t we just put a bunch of step-up generators in a row and increase our energy output several times over? Would this work or is there some law affecting my hypothesis?
Yeah, there is a law, it’s called the second law of thermodynamics. It says, basically that you can’t win, you can’t break even, and you can’t refuse to play. That leaves loosing as the only option.
Those things increase the voltage, not the energy. They use up some of the energy to make the remaining energy more usable. Eventually, you have to add more energy to make it all work.
<P ALIGN=“CENTER”>Tris</P>
“There ain’t no such thing, as a free lunch.”
– ** Robert Heinlein ** et. al.
Transformers work by trading off Voltage for Amperage. Total power is equal to Voltage times Amperage or Current. So, 100 Volts at 1 Amp carries the same power as 1 Volt at 100 Amps.
Transformers work by trading off Volts for Amps. Power at (say) 100 Volts and 50 Amps can be changed to 10,000 Volts at 0.5 Amps. (Actually, there is a slight loss of power in a transformer but the theory holds).
Power loss in a power line is based on the Amperage in the line and the Resistance ® of the line. Specifically, it is the Resistance times the square of the Current.
Transmission lines have a low, but non-zero resistance. Since the power loss in the line is based on the square of the current you want to make the current as small as possible. (Otherwise the power loss would add up over miles of power line). So, transformers are used to drop the current as far as possible.
Again, there is a slight power loss in the transformer at both ends, but it is much less than the loss that would occur in the lines if the transformers were not used.
“Drink your coffee! Remember, there are people sleeping in China.”
Dennis Matheson — dennis@mountaindiver.com
Hike, Dive, Ski, Climb — www.mountaindiver.com
Oh yes, Triskadecamus. Your sig line looks familiar for some reason…
Trisky is right, but just to elaborate a little:
Those transformers step up the voltage but reduce the current. In a perfect transformer (one of which you ain’t got) the product of the voltage and current remains constant across the input and the output. This product is the power, or rate of energy being delivered over time. Real transformers are not 100% efficient so the power output is slightly less than the power input. The rest goes into heating the transformer.
It’s like putting your thumb over the end of the garden hose – you increase the pressure by reducing the flow, but you can’t increase the pressure and flow at the same time without adding energy to the system.
Let’s see. I lathered and I rinsed. But did I repeat?
Don Lancaster, an old-time electronics guru, pointed out that if we did find a cheap source of infinite energy that the earth would soon become subject to major global warming.
You see, all the things that you hook up to the power would generate waste heat, and if everyone in the world used energy indiscriminately…
How about this energy idea:
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Manufacture two giant powerplants with the capability to safely store and manage vast amounts of electricity. Fabricate them like the ISS (in componants).
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Using nanotechnology, construct heavy duty carbon steel chords (or perhaps what we have today is sufficient given enough thickness).
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With a series of launches (easier if most of it could be built in space) construct one of the stations into low earth orbit and the other in the upper atmosphere.
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Connect the two power stations with the metal chains/chords.
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Start storing the immense electricity generated by the metal chords dragged through earth’s intense magnetic field.
Yeah, the cost of this venture is in the trillions, but the result of free, limitless energy is priceless.
How’s the science of all of this?
Hell is Other People.
Sake Samurai asks, reguarding his Whole Earth Dynamo
Tenuous.
If it was possible, which it ain’t, you would be able to draw power from it until you had stopped the Earth’s rotation. The energy you use has to come from somewhere. In the hypothetical case here, it is the kinetic energy of the Earth’s rotation, which is finite, although large.
<P ALIGN=“CENTER”>Tris</P>
Isn’t it interesting that the same people who laugh at science fiction listen to weather forecasts and economists?
–Kelvin Throop, III
The energy comes from slowing down the chains. So you can only get out as much energy as you put in putting the whole thing in ordit, and it crashes back to Earth at the end, killing millions. Hmmm, might be worth it after all… :o
OK, I’m kidding about that last sentence.
It is too clear, and so it is hard to see.
As noted, the energy comes from the sat (Faraday’s law says the induced current sets up a magnetic field opposing the one you’re moving through). This may be useful, but you can’t get unlimited amounts of power. But interestingly, this means you can use the concept in reverse: pumping current through the tether to boost the orbit of a satellite. By running the system both ways, you can futz with your sats orbit without expending propellant!
Now, if we’re permitted to gloss over details like technology limits and production logistics, one could imagine such a system using the moon as the sat. The resulting loss of angular momentum would be insignificant, so while not theoretically limitless, it would be almost so on wimpy human-scale terms. But there are probably other, easier ways to extract usable energy from the earth/moon system. Tidal energy might be one. There’s an awful lot of solar energy up for grabs too.
peas on earth
Continuing the drift off topic… I’ve seen plans for a series of “mega-engineering” projects to produce power on a vast scale. One involves building a dam across the Straits of Gibraltar and another was to place large turbines in the Gulf Stream off the coast of North America. (A smaller project involved cutting a canal from the Mediterranian to the Quattra Depression and puting a dam and turbine on the canal.)
I found a lot of these in a book titled New Earths by Oberg. It’s a book on how we might go about terraforming planets.
“Drink your coffee! Remember, there are people sleeping in China.”
Dennis Matheson — dennis@mountaindiver.com
Hike, Dive, Ski, Climb — www.mountaindiver.com
bantmof: I thought about using the moon, too - although 250,0000 miles of tense, electrified steel chord is a frightening thought. We could easily power a lunar base for billions of years though, and I supppose some sort of shielded mag-lev supersonic vehicle could shuttle supplies from the earth to the moon and back easily using that chord as track.
tanstaafl: It’s my opinion that we will never successfully terraform a planet. I think the abundance of planets will yield several choices for habitable planets and moons without resorting to planetary hocus-pocus. Besides, who wants to wait 1,000+ years for a planet to become openly livable?
Hell is Other People.
Well, once you have your energy stored in orbit, how do you use it for anything?
If you can solve this problem, then you don’t need the moving conductor in Earth’s (not particularly intense) magnetic field, you can just use solar energy.
O’Neill (I think) proposed geostationary space stations that would beam solar energy to Earth in the form of microwaves to collectors in unpopulated regions. There were some objections, notably the fear that an undirected beam could cause new unpopulated regions. Well, actually, there were ecological objections, but the main problem was the cost/benefit ratio. It didn’t get feasible until electricity costs get significantly higher than they were at the time.
KeithB: If we did find an infinite energy source, you say (or this energy guru said) that we would be subject to major global warming due to massive amounts of waste heat. This is probably not going to happen. There is no way we would be able to create such massive amounts of heat to create global warming unless there is so much carbon dioxide and other greenhouse gasses we can hardly walk outside without roasting. Even if huge amounts of heat were created, they would most likely dissipate before doing any damage.
We do have an infinite source of readily available power.
It’s called …the Sun.
And, while not eternal; it will last long enough for all practical purposes.
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Speaking of infinite energy sources, I just found this quote on Ford.com:
A fuel cell produces electricity by combining hydrogen and oxygen in an electrochemical reaction. Fuel cells require no combustion and the only emission is water vapor.
Sounds infinite to me. These fuel cells will be used in Ford cars in the very near future (as in a few years).
yeah, but it takes a lot of energy to make the oxygen & hydrogen.
And you’re planning to get the hydrogen from where, Llardball?
Getting hydrogen from water requires that it be electrolyzed. The energy that you get from this is equal to the energy that you get from recombining it.
Since neither the electrolysis nor the recombination in the fuel cells can be perfectly efficent, the net energy that you get out of the combination is less than what you put into it.
As Triskadecamus points out, the Laws of Thermodynamics tell us that we can’t win, we can’t break even, and we can’t even get out of the game (even though every major philosophy tells us that we can break one of those laws).
OTOH, we have plentiful supplies of free energy. As someone (maybe Freeman Dyson, but I’m not sure about this) has said: “In the short run, we have fossil fuels. In the medium run, we have fission. In the long run, we have fusion. Nature has been kinder to us than we have any reason to expect.”
“Kings die, and leave their crowns to their sons. Shmuel HaKatan took all the treasures in the world, and went away.”
Off topic and probably better suited to Great Debates, but…
Sake Samurai - Well, there may be (and probably are) habitable planets around other stars, but how close are they? If the nearest one turns out to be any distance away (and the nearest stars aren’t looking too good last I heard) any trip to them is likely to take a good number of years itself. Compared to a 100 year space voyage a 1000 year terraforming program suddenly doesn’t look too long.
Also, any habitable planet probably already has life of some form on it which is probably incompatible with us. We will still have to take our own food crops and the like and will have to worry about inserting them into and protecting them from the local ecosystem. Starting with a barren planet may actually be easier in the long run.
Faster than light travel and fully compatible ecosystems render this argumement moot of course, but I think both of them are probably going to remain in the realm of science fiction for some time.
“Drink your coffee! Remember, there are people sleeping in China.”
Dennis Matheson — dennis@mountaindiver.com
Hike, Dive, Ski, Climb — www.mountaindiver.com
LLardball:
The heat cannot “dissipate.” It stays on the earth. Everytime you run your car you are increasing the temperature of the earth. (As the earth get’s hotter it will radiate more, but I do not want to be around to see that happen.)
The statement did not apply to a large solar plant, or something like that, but to “free energy” sources. If you could make a cheap unit the size of a D battery power a car, pretty soon there would be enough of them to signifigantly alter the heat burden. What would happen if everyone on earth used energy the way the US does?