The use of pumps, air compressors, and simulators, and
heat, ventilation, and air-conditioning (HVAC) units, could
greatly increase power requirements. An on-site total energy
system might be a practical alternative. Such systems consist of
a mechanical package on site that provides utility services
(e.g., electrical, heating, air-conditioning) for use in buildings.
The largest portion of the electrical needs is usually dictated
by the number of buildings and their purposes.