I've always said this is true. Earth's force field which keeps the solar wind from sterilizing the surface, takes energy to operate. Also our continents move around, slowly, but imagine the diesel bill if we did that with tractors.
There must be a giant dynamo of molten iron circulating and that can't be a perpetual motion machine. There must be a fuel source. And we have ruled out U and Th as inadequate. We know the inner solid core is so much hotter than the liquid core that it sends up vortexes of molten NiFe. Why is the solid part hotter? LENR maybe.