Abstract: It is vital for energy utilization to reduce energy loss,to evaluate energy efficiency scientifically and to formulate effective energy saving measures.In this paper,energy losses were sorted systematically and some concepts were presented,such as direct energy loss,indirect energy loss,concomitant energy loss,independent energy loss,which is helpful to judge whether energy saving measures are effective and to determine the design direction of energy saving measures.Meanwhile,this paper illustrated energy consumption in production by proposing energy loss ratio.Moreover,indices of energy saving potential were defined and an application demonstration was given,which can help policymakers to develop energy saving measures and evaluate the effectiveness of different energy saving measures.

Key words: energy losses classification, energy efficiency evaluation, energy utilization efficiency, energy loss ratio, energy saving potential