Typical facilities derive their power from two sources. Natural Gas and Electricity. Most facilities must burn NG to generate hot water. Boilers can be efficient but Co-generation equipment generates hot water slightly less efficient than a boiler but then produces an equal amount of energy in the form of electricity.

Cogen v convenctional efficiency comparison

Conventional Technology

Uses two fuel sources for electricity & heat
Delivers both at 50% efficiency

Cogeneration Technology

Uses one fuel source for electricity & heat
Delivers both at 90% efficiency
Reduces operating cost by 45%