The development of biogas in China

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China’s biogas industry began in 1930; research on water-pressure biogas digesters dates back to the 1930s. This type of digester is currently widely used in rural areas and has received international attention, being commonly referred to as the “Chinese-style biogas digester”. In 1936, the renowned scientist Professor Zhou Peiyuan built a hydraulic biogas digester in Yixing County, Jiangxi Province, to use for cooking and lighting; subsequently, biogas digesters were also constructed in Anhua Town, Zhuji County, Zhejiang Province, and Wu’an County, Hebei Province. In 1958, biogas was promoted in many provinces and cities across the country, but it failed to take root due to immature technology and a lack of experience. In the 1970s, due to a severe shortage of fuel in rural areas, attention was once again paid to biogas production, and efforts to develop it were intensified, sparking another wave of biogas development. Rural biogas use increased from 60 million households in 1970 to 7.23 million households in 1980. However, due to immature technology and the lack of professional construction teams, most biogas digesters suffer from significant quality issues; they can only be used for 1 to 3 years, resulting in situations where they become unusable even before completion ； By the mid-1980s, almost all of the rudimentarily built biogas digesters had been discarded. After the 1980s, extensive research was conducted on the theory and application technologies of biogas fermentation, yielding promising results, and biogas development in our country began to progress steadily. Since the 1990s, through years of research, development, and pilot projects, various regions have learned carefully from the experiences gained in biogas development, intensified scientific research efforts and pilot projects, resulting in significant breakthroughs in biogas technology. The development of biogas production has gradually matured, from pool design and construction to operation and management. The fermentation processes and comprehensive utilization technologies are at the world’s leading level, enabling the vigorous growth of the biogas industry in China. In our country, research on biogas is closely linked to agricultural production activities such as the resource utilization of waste, the comprehensive use of biogas fermentation products, and ecological environment protection. This has given rise to various development models for rural biogas, including the \"pig-biogas-fruit\" model in the south, the \"four-in-one\" model in the north, and the \"five-complementary\" model in the northwest (which adds solar heating systems and greenhouses to the pig-biogas-fruit model). . From an average of 360,000 new biogas digesters added each year during the Eighth Five-Year Plan period, to an average of 750,000 new ones per year during the Ninth Five-Year Plan period, by the end of 2000 there were 9.8 million biogas digesters in use in rural areas across the country, of which 55% were used for comprehensive applications. At the same time, the construction of large and medium-sized biogas plants in livestock and poultry farms began, with a number of demonstration projects being built successively. By the end of 2004, 14.5 million rural household biogas digesters had been installed nationwide, along with 1,960 large and medium-sized biogas projects. Since the early 1990s, the construction of large and medium-sized biogas projects has placed emphasis on their environmental benefits, while also striving to enhance their economic benefits through comprehensive utilization. Such projects are designed and managed as systems with multiple functions, and their overall benefits are achieved through high-quality design, construction, and superior supporting equipment. Various new and efficient fermentation processes have been developed, increasing the processing capacity of anaerobic digesters by 2 to 10 times, the gas production rate by 1 to 3 times, and the COD removal efficiency by 10 to 20 percentage points. The emergence and successful application of these devices not only signify an improvement in the level of biogas engineering technology in our country, but also lay a solid foundation for the further promotion, application, and commercialization of biogas projects in livestock and poultry farms. Currently, the goal of biogas technology has shifted from \"energy recovery\" to \"environmental protection.\" The use of biogas is no longer limited to lighting and cooking; it has evolved to include centralized gas supply in rural areas as well as biogas power generation. Moreover, comprehensive utilization of biogas residues and liquids has been implemented, giving rise to ecological community development projects that rely on biogas to improve people’s lives. These efforts encourage farmers to change their traditional ways of living and working, thereby enhancing their quality of life. With the leadership and support of various ministries, provincial and **-level specialized organizations for biogas have been established, creating a technical management and service system for rural energy development. Training has also been provided for personnel involved in biogas technology, management, and maintenance, thereby ensuring the progress of the biogas sector. The development of rural biogas has received great attention from the ****, the State Council, and local party committees at all levels. People from all sectors of society as well as the vast number of farmers consider rural biogas projects to be energy projects that help build a resource-conserving society, ecological projects that support the sustainable development of agriculture, projects that increase farmers’ incomes, clean-up projects that improve rural living and production conditions, and projects that bring real benefits to farmers.