Why can't we use the earth's magnetic field to generate natural electricty?

Answer 1

To generate an electric current you need a conductor (e.g. a wire) moving in a magnetic field. The Earth rotates around its axis, so a wire on its surface would be moving, unfortunately the magnetic field generated by the Earth's core also rotates around the same axis at the same speed, so the wire does not move with respect to the field and there is no current. If you were to move the wire yourself, you would have to exert energy to do so, so you wouldn't get free power, only what you put in. And since the Earth's field is so weak, that method is unpractical anyway - you'd get better result by using a fixed magnet next to the moving wire, which is how generators work.

An interesting theoretical application of planetary magnetic field is tether propulsion for space crafts, which would require no propellant, only a power source. If a space craft were to use that method to accelerate, then the Earth's spin would slow down, if only ever so slightly that it would be impossible to actually measure. See more info in the link below.

Answer 2

Only an orbiting body would be capable of using the Earth's magnetic field to generate electricty (There has to be a speed differential between the conductor and the Earth's rotational speed).

According to the NASA website, they tried this experiment on the space shuttle once.

Answer 3

To conduct electricity with the use of magnets, one would have to move the magnet back and forth through a coiled wire to generate electron flow (aka current). Power plants generate electricity by turning magnets in a coil of wire. Earths magnetic field fluctuates, but does not move in the way required to harness energy.

Answer 4

The earth would stop turning.

Answer 5

becasue it's very very weak, look how easy it is to disrupt a compass!

Answer 6

We could, but where is the profit in that?