The Energy Booster is one of the least known Boosters, this name was never even mentioned in the series and was confirmed by the show's creators outside of the episodes themselves. The only mention of a Blue Draconium Booster ever made on the show was during discussions of the 5 colours of balance.
It is undecided to the viewer audience as to whether Lance Penn will be the Energy Booster, due to his young age. Most likely, however, he will be chosen as this Booster; other evidence that points to this conclusion are the events of Episode 7: The Horn of Libris, where Beaucephalis used Lance's energy to help calm the angry Libris instead of using Khatah's, as well as energy being drawn from 3 other confirmed Boosters for the same purpose.
In the unreleased Episode 0: The Alchemist, it is revealed that Connor Penn eventually found the Bone-Marks of the original Energy, Fire and Power Boosters. It is highly likely that he still has them stored away somewhere today, and if Lance does indeed become the Energy Booster, he may be given the Blue Draconium bone-mark of Ponderrah so that Fracshun can be made strong and pure.