Geothermal Generator

The Geothermal Generator was invented by Wheeljack and installed at the base of Mount St. Hilary. It is able to convert the Earth's heat into energon cubes.

Fiction

Marvel The Transformers comics

The invention of the Geothermal Generator was key in allowing the Autobots to function without being dependent on humans for fuel. Previously, under Optimus Prime's leadership, the Autobots got their fuel supplies through a deal made with G.B. Blackrock. Grimlock would have had no qualms with taking fuel from the humans, but this device meant he didn't have to. The Geothermal Generator provided enough energy to power the newly repaired Ark. Used Autobots