In the 22nd century fission, the nuclear technology of splitting uranium or plutonium, had proven highly toxic and environmentally dangerous. The Fusion Plant became the era's newest source of power. Built from the laws suggested by Unified Field Theory, the Fusion Plant operated as a small sun. Within the Plant, two hydrogen atoms were combined to form a single helium atom, releasing a torrent of energy. The energy wars of the 21st century soon faded to a distant, if painful, memory.