To keep balance you'd still have to lower all energy by an equal percentage universally so that the buffed ships are equal to their pre-buff ratio to nerfed ships.
At the moment in a duel, fighters really don't have an energy problem. So this is a pretty hollow proposal. It makes full-faction easier to handle energy, but non-faction gear on your ships really is no worse than before, thus still breaking balance. Extra energy is not nearly as useful as a 25% buff to your DPS, or a 25% buff to your dodging ability.