Combined heat and power (CHP), or co-generation, is the simultaneous generation of useful mechanical and thermal energy in a single, integrated system.



When separate electricity generation is processed, approximately 31% of the fuel energy can be converted into net electric power output, the rest of the energy input is lost as “waste heat” of the power plant. Typical boilers for steam production convert 80% of the fuel input into useable thermal power. If for example a paper mill requires 30 units of electricity and 45 units of steam,154 units of fuel are necessary to operate the process. The overall efficiency can be calculated:


ŋ = Puse/Pin = (30+45)/154 = 0.49

ŋ = 49%


A co-generation process uses the waste heat from the electricity generation step and therefore requires less energy. Only 100 fuel units are necessary to supply 30 units of electricity and 45 units of steam to a paper mill, therefore the efficiency is much higher.


ŋ = Puse/Pin = (30+45)/100 = 0.75

ŋ = 75%

Created with the Personal Edition of HelpNDoc: Easy CHM and documentation editor