When something falls down, potential energy is transformed into kinetic one. Furthermore, you can attach a pulley and extract some energy (like in an aljibe), for example with a dynamo... If the object fall in a deep well, we can extract more energy, till the object reach downhole..
But what if we could have a "bottomless pit"... Endless energy?.. Well we would need an infinite earth... Or like a "black hole aljibe"... hmmm that doesn't seem an option..
Oh, wait a minute, we already have one! A satellite is like always "falling down"... Then is exchanging "potential energy"(who knows from what reference system) into kinetic energy..
What about tied it to a pulley (a long rope I see) to a dynamo, or an earth winding with a magnet satellite, or a satellite winding with the earth magnet, or whatever.. The idea is to USE the "bottomless pit" energy..
Where is the mistake? (just in case there be any =P)