The closest we’re likely to get to “perpetual motion” any time soon is by harnessing the gravitation potential of the moon through tidal generators, or our nearest handy giant fusion reactor, the Sun, through solar power and indirectly through wind farms. And even then, eventually the sun will fade away, and the moon’s orbit will shift…
Knowing how these things tend to go, eventually the energy requirements of the human race will become so great that we’ll remove so much gravitational potential from our planet that we end up deorbiting it into the sun.
