Analysis of reliability and fault resilience of a biogas plant with a cogeneration unit in the power supply system of an agro-industrial complex

Abstract

This paper analyzes the reliability and fault tolerance of a biogas plant with a cogeneration unit as a complex electrotechnological system. Fault tolerance is considered an integral aspect of reliability, reflecting the system’s ability to localize failures, maintain partial operation, and restore functionality. The plant’s stability depends on coordinated operation of substrate preparation, anaerobic digestion, and energy conversion subsystems. The system exhibits predominantly serial reliability, where failure of critical components can disrupt the entire process. The study applies structural reliability analysis and exponential failure models, considering both serial and redundant configurations. Key indicators include MTBF, MTTR, expected failures, and availability. Major failure factors are aggressive biogas conditions, substrate variability, thermal instability, mechanical wear, and electrical system faults. The cogeneration unit is identified as the most critical element, contributing over 65% of downtime. A case study shows a total failure rate of Σλ = 1.07 failures/year, with reliability R(1) ≈ 0.40–0.43 and about one failure per year. With preventive maintenance and partial redundancy, downtime is limited to 22 hours annually, and availability reaches A ≈ 0.9975. The results indicate that system performance is determined not by complete failure-free operation, but by fault tolerance and rapid recovery. Practical measures include redundancy of key components, automated monitoring, and optimized maintenance strategies.