Starship phasers

Starship phasers are the primary weapons used by the Starfleet of the United Federation of Planets. They use the same operating principles as hand-phasers, but they are much more powerful.

Firepower

The phasers on a Galaxy-class starship can deliver at least a terawatt of power. Because phasers create chain reactions in their targets, the damage they inflict can be disproportionate to the energy delivered.

Firepower Examples

TNG "Who Watches the Watchers"

4.2 GW of power will supply a small phaser bank. What constitutes a "small" phaser bank is unclear.

TNG "Best of Both Worlds, Pt 1"

The power output of the Enterprise's weapons -- including phasers -- is far less than the potential output of its main deflector dish.

TNG "Night Terrors"

A deflector dish blast releases less energy than the exothermic chemical reaction of hydrogen and another exotic compound.

TNG "A Matter of Time"

A high-power burst from the phasers can be difficult to control to within a 0.06 TW (60 GW) tolerance, indicating that TW-range output is possible but control is limited at such high power levels.

Star Trek: Insurrection

A chemical explosion of low-density metryon gas is more effective as a weapon than the Enterprise-E's phasers and quantum torpedoes. Prior loss of the warp core probably affects phaser power, however.

ST:TNG Technical Manual (not a canon source)

The power output of the Enterprise's phaser arrays is 1.02 GW.

Range

The range of starship phasers is difficult to determine, largely because examples tend to be contradictory. When seen on screen, hostile ships invariably close to within a few kilometers of each other before exchanging phaser fire, but dialogue often suggests far greater ranges.