Source: Complete Arcane
You have greater power manipulating the energies of your heritage.
Prerequisite: Draconic Heritage.
Benefit: Your caster level increases by 1 and you add 1 to the save DC of all arcane spells with the energy descriptor of the same energy type as determined by your draconic heritage.
Special: If the Energy Substitution feat is used to modify a spell, this feat will work if the new type of energy matches the energy type of your draconic heritage.