Source: Dragon #313
Your skill with manipulating hard, or force, energy allows you to add physical force to spells and powers instead of converting existing energy to force.
Prerequisite: Harden Energy.
Benefit: For every 3 power points or 1 spell level expended, you may add 1 die of bonus force damage to any spell or psionic power that has an energy descriptor (maximum one-half the effect's normal base damage dice). If the target is entitled to a saving throw, it applies to this bonus damage as well. You cannot expend more power points than your current total, nor can you spend more spell levels than those you have remaining. You can use Concussive Blast on a spell altered by Harden Energy, but you do not need to do so.
The hard energy portion of the damage can affect incorporeal creatures, ignoring the standard miss chance. The remaining energy damage of the spell or power remains subject to the standard 50% miss chance with respect to an incorporeal target.
Special: Unlike other metamagic and metapsionic feats, Concussive Blast may be applied to a spell or power more than once. Each application on a spell requires 3 power points (or multiples of 3 power points if multiple dice of damage are added). Each application on a psionic power requires spell level (or multiples of 1 spell level if multiple dice of damage are added).