Using the electric induction stove and rotating magnets achieve the same effect: alternating magnetic field in a ferrous mass. Electric motors have efficiency u

Using the electric induction stove and rotating magnets achieve the same effect: alternating magnetic field in a ferrous mass. Electric motors have efficiency up to 95%, and there's no further loss in this system. If you are truly off the grid, you'd come about even using the rotating magnets from mechanical power (say, an ICE) vs converting that power via generator and powering a stove.