Phasers, disruptors and other beam weapons are armed directly from the warp reactor. They can use emergency batteries though (TWOK Scotty mentions the batteries being the only power available, but could still give Kirk "a few shots").
Photon and Quantum torpedoes are effectively "missiles", a physical warhead with micro-warp engines for propulsion. They contain matter/anti-matter, but require to be powered to arm them. Their ammunition is limited, and the possibility of running out of them has been mentioned (TNG The Pegasus, Star Trek Nemesis). DS9's Starship Down also shows that Dominion torpedoes are a physical, rather than energy, weapon. The fact that Scotty and Kirk never discussed photons in TWOK at that point indicates that perhaps the arming power for a photon is considerably more than to fire a phaser-bank.
In theory, new torpedoes can be manufactured, but the matter/anti-matter warhead may be impossible.