Biogas energy generated from livestock manure in China: Current situation and future trends.

This article investigates the current status of the livestock industry (cattle, pigs, sheep, and poultry) in China and assesses the potential for biogas production from anaerobically digested livestock manure. According to calculation results based on the latest data of livestock released by the National Bureau of Statistics of China in 2018, China produced 2 × 1012 kg of manure pollution in 2017, with pig waste representing the largest single manure source. Biogas that can be converted from high organic containing manure is a kind of clean bioenergy with low carbon footprint. In 2017, the energy potential from manure-produced biogas was about 5.74 × 1012-6.73 × 1012 MJ, which corresponds to 4-5% of China's total energy demand. Correlation analysis between biogas production and the livestock industry showed that crop production had significant effects on manure-generated biogas production. However, it is necessary to address the challenges when applying AD technology. Bioenergy potential from manure will be lost during material collection and transportation. Although large-scale livestock farming remains controversial, this type of farming can improve the energy recovery rate of livestock manure. How to gain benefits and maintain sustainable development is also a bottleneck for AD promotion. Reducing energy input in AD projects as well as enhancing the efficiency of methanogenesis of livestock manure are key factors for achieving a high net output of biogas projects. More inclusive strategies and a broader vision should be adopted to allow stakeholders to benefit from manure-generated biogas projects.