Comparison of different crop residue-based technologies for their energy production and air pollutant emission

Crop residue (CR) based-technology has several benefits, including renewable energy production and improvement in the environment and waste biomass management. However, the quantitative assessment of different CR based-technologies in terms of these benefits is limited. In this study, three typical CR-based technologies, CR biochar (CR-BC), CR direct-fired power (CR-DFP), and CR briquette biofuel (CR-BB), were assessed in terms of energy- and environment-related performances using a mixed-unit input-output life cycle assessment method. The results indicated that CR-BB performed better in energy production and air pollution mitigation than the other two technologies. Energy conversion efficiency was suggested as a key factor in determining the potentials of bioenergy production and environmental improvement. Furthermore, based on the energy demand from the Chinese agricultural sector and CR supply in 2012, the energy supply capacity (ESI) of CR-BC, CR-DFP, and CR-BB was estimated to be 24.3, 2.89, and 53.0, respectively, and their total greenhouse gas (GHG) reduction potential (TR_GHG) was estimated to be 1.41 × 10⁶, 4.81 × 10⁶, and 1.68 × 10⁶ t CO_2e (CO₂ equivalent), respectively. Overall, the CR-DFP and CR-BC are recommended for the high-value utilization of CR resources. The findings of this study could provide a basis for the development of CR-based technologies and CR management policy.