How this ability is gained varies, from either harsh training, to genetic inheritance, or power bestowal from either Monster Cells or God.
When used, its effects are shown to vary in power depending on how powerful the user is, but they are still nonetheless potent, as seen when Boros' energy wave had the capacity to destroy the entire planet, and when Suiryu greatly struggled to deflect Choze's energy wave.
Murata has stated the energy spheres used by Vaccine Man, Homeless Emperor and Choze are the same. Whether this means they all able of performing the same technique or how is it even possible is currently unknown.
Boros is, by far, the most powerful user of this ability.