Fusion Power

Fusion power is how the sun works. Light atomic nuclei (like hydrogen) fuse together at super high temperatures to form heavier nuclei (like helium). The process releases massive amounts of energy without producing radioactive waste or greenhouse gases. Fusion is considered to be the holy grail of clean energy. But even after many decades of intensive research, there is not yet a way to maintain the temperature, density, and confinement to have a fusion reaction go on long enough to produce continuous net-positive energy output.