Techno-Economic Analysis of a Combined Biogas Heat and Power System: Case Study of a Typical Livestock Farm in Iran

In this paper, the biogas produced from a fermentation livestock waste tank with 443 cubic meter volume, in an animal farm in Iran is investigated. The farm has 3055 dairy cows and the produced biogas is supposed to be used to run a CHP system. Every day 30 cubic meters of livestock is processed in the digester. Using the developed model and data obtained from the farm it was found that, the monthly 53910 cubic meter of produced biogas can operate a 350 kW dual fuel compression ignition engine CHP system. The annual cost saving, percentages of system profitability index and payback period are 1142.2, 34% and 3.7 year, respectively. Finally, a sensitivity analysis is carried out to show how the profitability of biogas CHP plants would vary due to changes of some key parameters such as prices of diesel fuel, electricity and electricity buyback. It should be noted that this study is carried out for the year 2017.