One of the reasons I never cared for the alien blaster (and never went after the firelance) was that the ammo and repair part supply for both seemed … lacking. Really lacking.
I don't remember any (or much) being in Mothership Zeta, either.
How much is there actually in the game (without the benefit the scavenger perk), both in the regular game and Mothership Zeta.
Best Answer
According to the Wiki article for the ammo: Alien Power Cell
(That link also contains the locations.)
In the core game:
Entirely:
In Mothership Zeta, there are: