Part of a wind power generating device consists of metal parts (a conductor) moving through the earth’s magnetic field. By doing so, as I recall, an electric current is generated in the conductor. Now I’m sure no such device captures this current, since it must be minuscule. My question is, just how much power would this add up to if it could be captured? For number of wind power generators, I’m thinking that it would be the number of such devices currently online in the U.S.
Yes, any conductor moving across a magnetic field will generate a voltage across it.
Doing something useful with this voltage is another matter entirely. For instance, if the turbine turns so that its plane of rotation is parallel to the local magnetic field, the voltage falls to zero. The voltage goes from one side of the disc of rotation to the other, but there’s no contact there to allow the current to flow back through a non-moving conductor. Last, Earth’s half-gauss field is very small and not very useful for a generator (as noted above).
A system something like this has been proposed to generate electric power on satellites, using the ~8000 m/sec orbital speed and the near-earth plasma as the return current path. Look up “electrodynamic tether”.
on: 4th November 08