Depends upon capacity of plant and total operating head . . .
Headgate hoist motors.
Security system, including cameras, motion detectors and all-night flood lighting to deter vandalism, if provided [minimal load].
Additional lights for if the operators or maintenance personnel need to see at night [minimal load, if modern high efficiency lights sources are employed; more if incandescent bulbs are used].
If weather goes below freezing: stilling well heaters to ensure headwater elevation measurements remain accurate; gain heaters to ensure headgates will drop in event of triggering of emergency shutdown procedure, instead of being frozen and not dropping, possibly leading to destruction of unit/plant; space heaters to ensure interior temperature of building is maintained at some small nominal value above freezing.
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]