Empire — Clifford D. Simak

Who controls power controls the Solar System, and Interplanetary Power, through its power accumulators controls power. Spencer Chambers, the president of Interplanetary Power, used that control to rule the Solar System with an iron thumb that allowed no dissent. When Russell Page and his friend Harry Wilson develop and alternative source of power they find themselves drawn into a conflict that will decide the fate of the system, and whether man will live in freedom or as slaves. Will they succeed, or will Interplanetary Power keep its Empire?