Let's say I'm fighting somebody who can only be damaged by energy, and because of either an oversight or rampant pacifism, all I have are the Create [Intensity type goes here] spells to attack with. Can these spells damage energy if I use them to attack with?
If you have access to the contents of the Arcana Exxet: Secrets of the Supernatural book then there is another potential option open to you should you happen to have at least 15 extra magic level to spend. Using the Metamagic in the Arcana Shepirah you could buy the Energy Control sphere under the Arcane Esoterica tree. This grants the following ability:
The wizard can spend 10 Zeon points when casting any Attack spell to make it capable of damaging energy. Thus, even an Air Cut or Earth Spike would have sufficient mystical power to affect immaterial beings or beings immune to attacks not based on energy. Similarly, he can spend 10 Zeon points when casting any defensive spell in order to make it deflect energy, even when the spell does not normally permit it. Arcana Exxet: Secrets of the Supernatural pg. 27
While not purely RAW for this sphere to work on an 'effect' spell, it is a fully justifiable house-rule to adopt to cover spells that can be used to attack.