DECENTRALIZED BIOMETHANE INJECTION AND ORGANIC FERTILIZER RECOVERY: ECONOMIC AND ENVIRONMENTAL EVIDENCE FROM RURAL PUNJAB, PAKISTAN

Abstract

This paper assesses the financial and environmental sustainability of the decentralized village-level biogas systems that inject the purified biomethane into the Pakistani natural gas grid and produce livestock waste organic fertilizer. In rural Punjab, having very dense farm stock animals and unsaturated organic waste, the study develops a deterministic economic-environmental model that incorporates energy generation, fertilizer recovery and emission of greenhouse gases reduction. According to findings, a typical biogas unit with the size of the village of 10, 000 people is expected to generate approximately 247 m3 of grid-quality biomethane and four tons of organic fertilizer daily if it is fed on 10,000 kg of livestock dung per day. The financial analysis shows that it has a good commercial viability and the internal rate of return is above 25 percent and the net present value is positive at more than a decade. Environmental evaluation displays a significant amount of methane reduction, equating to the saving of approximately 277 metric tons of CO 2 -equivalent emission every year. Comparative evaluation shows that biomethane provides energy at a much reduced cost per kilowatt-hour as compared to imported liquefied natural gas (LNG), and enhances energy security, rural monetary gain, and lessening of emissions. The sensitivity analysis ensures that the viability of the entire system is solid under a large variety of conditions both technical and in the market. The results indicate that decentralized biomethane systems are an affordable and scalable policy to decrease the LNG reliance, foster sustainable farming, and boost efforts to climate change and energy transition in Pakistan.