Climate mitigation potential of sustainable biochar production in China. (April 2023)

• Record Type: Journal Article
• Authors: Xia, Longlong; Chen, Wenhao; Lu, Bufan; Wang, Shanshan; Xiao, Lishan; Liu, Beibei; Yang, Hongqiang; Huang, Chu-Long; Wang, Hongtao; Yang, Yang; Lin, Litao; Zhu, Xiangdong; Chen, Wei-Qiang; Yan, Xiaoyuan; Zhuang, Minghao; Kung, Chih-Chun; Zhu, Yong-Guan; Yang, Yi
• Is Part Of: Renewable & sustainable energy reviews. Volume 175(2023)
• Publication Date: 2023-04
• Subjects: Biomass wastes -- Biochar production -- GHG mitigation -- Carbon neutrality -- CH4 and N2O emissions -- Agricultural systems; GHG greenhouse gas -- BC biochar -- WWTP wastewater treatment plant -- Mt million tons; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.rser.2023.113145
• Languages: English
• ISSNs: 1364-0321

Abstract

Abstract: While feeding 20% of global population, China's agriculture is a large greenhouse gas (GHG) emitter, posing a major challenge to the country's carbon neutrality target. However, the pathways of agriculture towards carbon neutrality remain unclear. To address this knowledge gap, we conduct a comprehensive life-cycle assessment and show that valorization of sustainable biomass wastes (crop residues, forest residues, livestock manure, food waste, and sewage sludge) into biochar can contribute importantly towards agricultural carbon neutrality in China. The maximum potential of biochar production from these waste resources in 2018 is 145 Mt yr −1 with a corresponding GHG mitigation potential of 455.7 (405.5–572.4) Mt CO2 -eq yr −1 . This can fully offset the total CH4 and N2 O emissions from China's croplands (∼400 Mt CO2 -eq yr −1 ), which are difficult to be entirely eliminated due to rice paddy irrigation and intensive use of fertilizers. Distribution of biomass waste varies across regions, and at the national level, crop residues (48.8%) and livestock manure (25.4%) and food waste (15.6%) are the main sources of biochar feedstocks and should be prioritized in biochar development. Forest residues have a marginal contribution due to competing uses from other sectors, and sewage sludge derived biochar is a net source of GHG emissions due to the large energy consumption required for sludge drying. The total GHG mitigation potential of biochar is greatly affected by pyrolysis temperature and the highest mitigation effect is observed under 300–500 °C. These results underscore the benefit of sustainable biochar production to agricultural carbon neutrality, and to maximize the climate benefit requires differential policies and pyrolysis technologies tailored to regional availability of biomass resources. Highlights: The GHG mitigation potential of sustainable biochar in China was analyzed. The maximum mitigation potential can offset all CH4 and N2 O emission from croplands. Biochar GHG mitigation potential is affected significantly by pyrolysis temperature. Sustainable biochar can contribute toward agricultural carbon neutrality.