Daniel Michaels, writer for the Wall Street Journal: There are eight widely distributed major sources of energy for humanity: solar, wind, hydro, bio-mass, fossil fuels, uranium and thorium nuclear fission and fusion. Solar heats the Earth to livable temperatures, evaporates water from the oceans and drives the wind. Wind carries evaporated ocean water over land and drops it as rain and snow to enable plants to grow and for drinking water. Bio-mass has provided fire for heating, cooking and industry since the beginning of civilization. Bio-mass can only support limited population and life is pretty miserable with this energy source. Fossil fuels and fission from uranium and thorium enable tremendous advances in technologies and support many more people. Fission can provide all of humanity's energy needs for a very long time. Fusion, the energy in the sun could provide all the energy we need. Can we master it? If it is so close to being realized, why is it being left to small startup companies? At lease one physicist and one nuclear engineer think that fusion is not close to ready for commercial use.