Planar Energy Fragments

I cannot find anywhere how to attain a fragment of planar energy. Any suggestions?

 

You're talking about the fragments for upgrading the Epic 2.0 Spells I assume. If so, then they're mostly gotten from the KA PQs. You can (supposedly) get them from the PoP & CD ones too, but the KA ones drop them more often. (Good luck.)

 

Best bet is the Obulus Frontier 'pq'. It doesn't have better return rate than the other KA PQs, but it is much, much shorter. You can easily solo it in CD or PoP gear and you can start it every hour if you've got a toon that can pick up the quest for it.
Note: You don't need the quest to get the reward, just to start it...