Development of a Biogas-Based Power Generation System for Swine Farms: Performance and Economic Evaluation

This study presents the development and performance evaluation of a biogas-powered electricity generation system designed for medium-scale swine farms. A conventional Hino V-22C diesel engine was modified to operate under spark-ignition mode using purified biogas as the primary fuel. The compression ratio was reduced from 18.5:1 to 14.7:1 to accommodate the lower heating value and slower flame speed of biogas. An Emergency Fuel Supply (EFS) system, automatically controlled by an oxygen sensor, was integrated to improve combustion stability during transient or high-load operations. Experimental tests were conducted to determine key thermodynamic and operational parameters including thermal efficiency, brake power, volumetric efficiency, and brake mean effective pressure. The generator achieved an electrical output of 80–120 kW, with the highest thermal efficiency of 11.66% at 100 kW under dual-fuel operation. The EFS system increased efficiency by approximately 22.7%, demonstrating its effectiveness in enhancing ignition quality and reducing cyclic variation. A techno-economic analysis was also carried out to assess the feasibility of implementing the system in a real swine farm. Results show that a farm housing 700 pigs per barn (six barns total) can produce approximately 30 kWh per housing unit, achieving a breakeven period of 15.79 months. The system not only provides a sustainable and cost-effective energy source but also reduces methane emissions from manure management, contributing to circular economy practices and greenhouse gas mitigation. Overall, the developed biogas generator demonstrates promising potential as a reliable, economically viable, and environmentally friendly decentralized power system for agricultural applications.