Comparison of biogas development from households and medium and large-scale biogas plants in rural China

As a renewable energy source, biogas not only alleviates energy shortage in rural areas but also effectively reduces the environmental risk associated with agricultural waste management. This study presents a comprehensive overview of development of household bio-digesters and medium and large-scale biogas plants (MLBPs) in China, and discusses the advantages and disadvantages of both biogas systems in terms of environmental performance, role in agriculture, economic benefit, government support, energy efficiency, societal influence, and resident living mode. Both systems have their relative strengths and weaknesses. The operation and maintenance of household bio-digesters are easier, and their environmental and economic performances are superior compared to those of MLBPs. However, MLBPs have higher energy efficiency and better social effect. Thus, the choice of a biogas generation system depends on the local circumstances. Household bio-digesters are suitable for undeveloped regions where the rural residents live far apart from each other, whereas MLBPs are suitable for developed regions where people live close together. The government can play a positive role in preventing the negative impacts of rural social structural change, such as those of urban migration of adults, on household biogas development. Additionally, establishment of scientific and technological support and service systems is recommended for further development of biogas in rural China.