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Scifi and Fantasy Forum: Speculation: Earth Power
Earth Power
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I haven't had physics yet...
An electrical generator works by somehow turning a shaft, which spins magnets in a coil (or something like that). Usually a wind/water/steam turbine, or piston engine turns the shaft.
The earth spins constantly...what if we put giant shafts into the north and south pole, and used the earth's spin to turn generators? How much energy could that produce? Would that gradually slow the earth's spin? (due to friction/heat loss) If it did quit spinning, would it go out of orbit? Would making the shafts really long and setting the generators out in space so that only the shafts were in the atmosphere reduce the friction enough to prevent that?
Posted By:  jubal Nov 18, 2002 - 09:57 pm |       | There are a lot of easier ways of obtaining free limitless power. I would start by researhing the experiments of Nikola Tesla.
| Posted By: Odrade Nov 19, 2002 - 06:27 pm | | Nice idea, but you are forgetting something. The Earth is not a hollow thing. There is some really hot stuff inside. Any shaft might just melt.
It is friction that helps to produce the electricity i believe. But there isn't friction in space that there is here on earth. Space is more of a vaccuum, without the constant friction experienced here. So don't think you could produce that energy. And what exactly (see i am picturing water turbines) is the opposing force for the earth's rotation suppose to have friction against?
Who knows, maybe i am all wrong on this. But with a water turbine, like at dams to produce electricity, the water is pushed by gravity against the turbine. And windmills, that electricity is created when wind pushes against the blades/propellors and forces them to move and generate energy. I think you need another force.
I was thinking the spinning of the earth would be the force. Instead of wind or water turning the shaft, the momentum of the earth would do it.
And the shaft wouldn't have to go all the way through the earth. Being a lot bigger than a telephone pole, it would have to be planted deeper, but I don't know how deep. Radial spokes at the bottom could brace it.
Friction isn't what creates the electricity, it's the opposite...friction is the inefficiency...the energy that can't be converted to electricity because it's converted to heat and lost. Energy from the turning shaft is converted into electricity, but not all can be converted because some is lost to friction resistance.
Ooh-kay, I found something in a book that says that the kinetic energy of Earth's rotation about its axis is 3.57x10^26 Joules, and could supply the world's energy needs (assumed to be constant at 2x10^20 Joules/year, although in reality it's increasing rapidly) for 1.79x10^6 years without increasing the length of the day by more than one minute. (I'd guess that's assuming 100% efficiency, which would mean no friction loss.) So...perhaps that answers my question.
There's also a bit of explanation of electrical generators. Mechanical energy from the spinning shaft spins a loop of wire between two magnets. The alternating magnetic fields create alternating charges, which alternately attract/repel electrons, which creates magnetic current. To run the current off through cables and use it to do stuff, the cables have to be connected to the spinning loop. The connection is where the friction occurs. Because the loop is spinning, you can't connect the cables directly (else they'd just wrap around it), instead you have the ends of them rubbing up against the loop.
| Posted By: Nomad Nov 20, 2002 - 07:43 am | | OK, but what would hold the generator still relative to the position of the earth?
| Posted By: Odrade Nov 20, 2002 - 06:39 pm | | How would you store this energy after it has been generated?
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