They are found commonly in "alien crates" and the inventories of almost every enemy aboard Mothership Zeta. It should be noted that when picking up any alien weapon which uses this ammunition the contents of its magazine are transferred to the player's inventory, so picking up all available alien weapons is advisable, even if they are only to be dropped later.
At the end of Mothership Zeta, talking to Sally every 24 hours will give you a random alien item and around 40 alien power modules. However, you may or may not be informed that they have been added in your inventory. This means the alien power modules are unlimited, yet may take a while to accumulate in considerably large amounts.
It is identical in look to the alien power cell, however is much more common and is used in more weapons.
pcps3xbox360 The alien power module uses the standard item collection sound when being taken, instead of the ammunition collection sound.