ELECTRICITY, AN ENDLESS SUPPLY?

[eelyeroc]

I understand somewhat on how electricity is produced in mass quanities. By spinning magnets around copper coils.

But my question is this. Whether we use coal or nuclear power is electricity itself an energy that will last forever?

Where does it come from? Is it absurbed from the atmosphere or possibly the Earths magnectic field with the end product just being heat? Thus reducing the amount of elctricity that was in the original source?

If that is the case it would seem that there would not be an endless supply.

So the obvious question is, "are we destroying the Earth"s magnetic field or atmosphere by producing electricity?"

Anyone?

[Cap'n Refsmmat]

Electricity is merely a flow of electrons. Once those electrons are used, they don't go away -- you can run them through a generator again if you'd like. So no, we will not use up all the total electricity, though we may use up all of our fossil fuels.

[Reach]

[Horza2002]

If only that was true Reach....

[lemur]

I understand somewhat on how electricity is produced in mass quanities. By spinning magnets around copper coils.

But my question is this. Whether we use coal or nuclear power is electricity itself an energy that will last forever?

Where does it come from? Is it absurbed from the atmosphere or possibly the Earths magnectic field with the end product just being heat? Thus reducing the amount of elctricity that was in the original source?

If that is the case it would seem that there would not be an endless supply.

So the obvious question is, "are we destroying the Earth"s magnetic field or atmosphere by producing electricity?"

Anyone?

CRef basically explained it, but electricity is just a means of transmitting power from a generator to a resistor (could be a device or just resistance in the wire). Power has to be derived from a source, such as burning fossil fuel, or using radioactive reactions to produce steam and spin the magnets to make waves flow through the electrons in the wire. I believe that power lines have very high voltage to overcome the resistance of long lengths of power line wires. This voltage has to be "stepped down" by transformers before it can be used by humans. I'm not sure exactly how much power is lost in the process of transmitting it through the lines at high voltage, but I've heard it is a lot.

 

edit (correction): I just googled "electric power transmission" on wikipedia and it says that power loss decrease proportionally with voltage of the transmission line. So the most power seems to be lost in lower voltage lines. It does say, however, that some current can be lost by various levels of short-circuiting between power lines, though it doesn't specify how much.

Edited January 12, 2011 by lemur

[Marat]

A mirror reflecting light is doing work, but where does the energy for that work come from? Is the mirror more degraded the more it reflects light? Unless something is being used up in this apparently passive process, then a perpetual motion machine would be possible.

[Cap'n Refsmmat]

Photons lose a tiny portion of their energy upon being reflected. Also, no mirror can reflect 100% of the light hitting it; you'll at most get in the 90% range, with the rest absorbed by the mirror and lost as heat.