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1970-01-01

A bad question, as it has been doing that literally (rotationally) since before life started. This power is busy generating the magnetosphere. We would not be enjoying our nice oxygen atmosphere and would be as dead as Mars if Earth's rotation wasn't also powering a dynamo.

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It doesn't take any energy to maintain a static magnetic field though.

Earth's magnetic field isn't static, though.

Negligibly so. The Sun delivers more energy to Earth in about 5 seconds than the magnetic field loses in 1,000 years.

The magnetic field is coherent. The energy from the Sun is not.

The currents that produce the magnetic field are flowing in liquid metal with nonzero resistivity.

Earth's rotation is also generating the power that is moving the Moon's orbit slowly away from Earth. There will be no more total solar eclipses in 600 million years because of this.

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