This doesn't really make sense:

Basically the electrical energy is from the moving conductor's own kinetic energy and manifests as a drag force. No energy is tapped from the ambient magnetic field, instead it comes from the moving conductor - just like a regular generator doesn't tap "magnetic energy" from the field of the permanent magnets the rotor is moving in. Alternatively a conductor coupled to a power source in a magnetic field generates an accelerating force, thus providing a form of propulsion - again just like an electrical motor.

Look, the principle of generating electricity with a tether is just an application of good ol' Faraday's Law - moving a conductor through a magnetic field will generate a potential across the ends of the conductor. A current is induced if the circuit is closed by artificial means or perhaps through the plasma in the ionosphere.

No-one is talking about "tapping energy from magnetic fields" or "coupling conductors to power sources". It's just Faraday's Law on electrical induction from the relative motion between a conductor and a magnetic field.

All I wanted to know, is why this in turn should result in the loss of mechanical (ie. kinetic) energy of orbital motion. Alcaray suggested something along the lines of what I would imagine is back-emf. The back-emf resists the motion in an alternator and I guess he thought a similar thing could somehow apply to an orbital tether.

Whatever the actual explanation, you came no closer to it with your last post.