When antimatter comes into contact with matter it annihilates: the mass of the particle and its antiparticle are converted into pure energy.

Antimatter is not a viable source of energy. Photograph: Flickr user HKmPUA

Unfortunately, however, antimatter cannot be used as an energy source. Although the annihilation of matter and antimatter releases energy, antimatter does not occur in nature: it has to be created. This requires in itself a lot of energy. Even the storage of antimatter requires a lot of energy.

The inefficiency of antimatter production is enormous: you get only a tenth of a billion (10^-10) of the invested energy back. If we could assemble all the antimatter we've ever made at CERN and annihilate it with matter, we would have only enough energy to light a single electric light bulb for a few minutes.