The term hotel load is used with respect to ships to describe their non-propulsion energy requirements. It can be thought of as the energy load required to operate all 'non propulsion' systems aboard ship - lights, air conditioning, computers, water purifiers, radios, etc. When a ship is in port, for instance, all of its energy requirements constitute* the hotel load. When a ship is underway, the excess in energy requirements over and above that needed to drive the ship is the hotel load. The term can be used to describe the actual electrical power draw, or to describe the amount of engine plant time and output required to produce that energy from the generators. Ships in port do, of course, have the option of accepting shore power to handle their hotel load and reduce time on their engine components, if sufficient power is available.
* Thanks to Simulacron3 and rootbeer277 for pointing out my boneheadedly incorrect use of comprise.