Energy management for maintaining anaerobic digestion temperature in biogas plants

This comprehensive review investigates the role of maintaining temperature in anaerobic digestion (AD), a process that converts biowaste from agriculture, industry, and municipal sources into biogas. As most regions experience significant seasonal temperature variations, there is a need to maintain consistent temperature within the digester to ensure optimal plant performance. Various approaches for maintaining desired temperature in digesters are discussed, emphasizing the positive impact of a stable digestion temperature on biogas production and process stability. For both internal and external heating systems, the potential of biogas, solar, fossil fuels, and geothermal energy as heating energy sources is analysed along with insulation approach for achieving a desired temperature within the digester. The economic aspects associated with these heating methods are addressed, providing insights into their feasibility and cost-effectiveness. The integrated renewable energy sources for heating such as solar-biogas, geothermal-biogas, and solar-geothermal-biogas, along with thermal insulation is recommended, but the economic feasibility of these systems warrants further investigation at pilot and commercial scale in different parts of the world. This review provides valuable insights to the AD plant developers, operators, and owners for designing AD heating system and maintaining desired digestion temperature.