To compare the environmental performance of the case study, greenhouse gas emissions cost was made. As a result of the combustion, the 1 m3 biogas produces 1.87 kWh/h electricity, which is equivalent to 1.96 kg CO2. The cost of greenhouse-gas emission should be added to the plant cost from the view point of globalwarming; thus, the cost of CO2 works out to approximately V6.84/t CO2 for the combustion of biogas in the CHP generation unit [31,32].