Fusion is the melding together of lighter atomic nuclei to form heavier nuclei, an action that releases roughly one million times the energy released by the burning of oil. The reason for the continued pursuit of fusion as a commercial source of energy is no joke. One day these fuels will be exhausted. Most projections show that severe shortfalls between global energy demands and fossil fuel supplies will begin to be felt toward the end of the 21st century. New sources of energy before then are a must.
Fusion is an excellent candidate.
Both of these isotopes can be obtained from ordinary water-deuterium is extracted directly, and tritium is produced from the element lithium. Enough fusion water to supply a year's worth of electrical power to a metropolitan city could be delivered in a pickup truck. Ironically, the holdup in the development of fusion as a commercial energy source has been an energy barrier. The analogy has been made that igniting a fusion reaction is like trying to light a wet match. Furthermore, the heated nuclei must be confined long enough to interact which poses another problem since heated nuclei tend to fly apart.