This paper adopts optimal model which used GAMS to develop methods and tools for conducting an integrated assessment of DER system. Three cases were studied. Energy-saving, environmental and economic efficiency were evaluated. The results of the simulation can be summarized as follows:
- For the current system, optimal operating time is about 4,132 hours per year and from 8 am to 22 pm every day.
- It is economical when electricity price increases or gas price decreases.
- According to the load function of system, energy-saving, environmental and economic efficiency will have a maximum value at optimal operating time.
- Compared with exhaust heat efficiency, power generation efficiency has more influence to the economic efficiency and CO2 reduction when the total efficiency is fixed.