In this post, Jiqin Ni, a professor of agricultural and biological engineering in College of Agriculture and member of the Purdue Institute for Sustainable Development, discusses his recently published article “A review of household and industrial anaerobic digestion in Asia: Biogas development and safety incidents”, which appears in Renewable and Sustainable Energy Reviews, with the support of the Purdue College of Agriculture, Agricultural Research and Graduate Education.
What did you want to know?
Anaerobic digestion is a technology widely used in the world for production of renewable energy (biogas) and reduction of greenhouse gas emissions. Asia has the world’s largest number of anaerobic digesters in countries with very diversified social and economic development. Knowledge about the successes, lessons, and challenges of anaerobic digestion are invaluable for the sustainable development of the technology.
In this study, we were interested in filling in research gaps in understanding anaerobic digestion implementation for the entire Asia. Specifically, we wanted to obtain insights into the historical, present, and future perspectives of biogas development in Asia and to promote workplace safety by compiling and presenting the first comprehensive biogas accident statistics in the continent.
What did you achieve?
The study revealed that anaerobic digestion was implemented for biogas production across 25 Asian countries that can be categorized into four groups based on their biogas development status. Asia has approximately 45.03 million biogas digesters, of which about 99.72% are household units and 0.28% are industrial digesters. Predominantly located in less developed rural areas, a substantial number of household digesters have ceased operation or been abandoned. Many industrial digesters smaller than 500 cubic meters are also underperforming. However, larger size digesters are better managed and more sustainable. Some Asian countries and regions are witnessing a transition from household to industrial digesters, driven by economic growth and favorable environmental policies.
From 1958 through 2023, 163 biogas safety incidents were recorded in seven Asian countries, resulting in 321 fatalities, 220 injuries, and substantial property damage. The average casualty rate per accident was approximately 10.8 – 39.7 times higher for death, and 1.5 – 8.1 times higher for injury than those reported elsewhere. The finding demonstrate that ensuring biogas production and utilization safety is a key concern.
The study also identified seven key factors influencing biogas development in Asia: climate conditions, energy demand, biowaste resources, economic development, government policy, technical service, and biogas programs. These factors range from objective and independent to external dependencies and direct, dynamic influences.
Future biogas development in Asia will benefit from favorable technoeconomic growth and increased climate change awareness, supported by societal priorities and government policies. However, it must also confront and address several significant challenges.
What is the impact of this research?
As one of the most applicable technologies offering multiple advantages in energy production and environment protection, implementation of sustainable anaerobic digestion can benefit from the experiences and lessons learned in Asia. For example, when planning biogas development programs, the quantity and stability of digester feedstock, which is usually biowastes from animal agriculture and agroindustry, are more important for individual digester systems than for a region or a nation. Favorable government policies in energy and environment, economic development, and technical resources and supports are critical for the success of large-scale implementation. Finally, safety measures should be taken for every digester system, and education should be provided to all individuals who own or operate digesters or use biogas as an energy source to prevent casualties and property damage.