Mehdi Jahangiri - Department of Mechanical Engineering, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran.
Fatemeh Karimi Shahmarvandi - Department of Biomedical Engineering, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran.
Reza Alayi - Department of Mechanical Engineering, Germi Branch, Islamic Azad University, Germi, Ardabil, Iran.

The use of small-scale Combined Heat and Power (CHP) to meet the electrical and thermal needs of buildings has grown exponentially and plans have been made in Iran to expand these systems. In view of the above, in the present work, for the first time, sensitivity analysis has been performed on the parameters of natural gas price, annual interest rate, and the price of pollutant penalties. The CHP system studied included fuel cell, biomass generator, solar cell, wind turbine, and gas boiler. The techno-econo-enviro simulations were performed by HOMER software and the study area was Abadan. The use of a dump load to convert excess electricity into heat and heat recovery in a biomass generator and fuel cell are other advantages presented by the present work. The minimum Cost of Energy (COE) is ۱.۱۶ /kWh. The results also showed that the use of biomass generators was economical when the annual interest rate was ۳۰ %. The significant effect of using dump load on the required heat supply and the lowest price per kg of hydrogen produced equal to ۳۵.۴۴۰ are other results of the present work. In general, the results point to the superiority of solar radiation potential over wind energy potential of the study area and the prominent role of dump load in providing heat on a residential scale is clearly seen. Also, for the current situation, using biomass is not cost-effective. 

CO۲ penalty, Interest Rate, Fuel Cell, Gas boiler