Greenhouse gas reduction through crop residue-based bioenergy: A meta-analysis of reduction efficiency and abatement costs of various products

Crop residue-based bioenergy (CRB) is a green replacement for fossil fuels and an effective way of utilizing crop residues. Understanding CRB's GHG reduction effects is critical for predicting its contributions to carbon neutrality. However, many studies have focused on single products or regional assessments, and results remain uncertain and lacking in systematic examination of the diversity in products, feedstock types and their supply. Therefore, this paper systematically investigates the GHG reduction efficiency, driving factors and abatement costs of principal CRB products using a database of 225 cases composed of 71 carbon trading projects and 154 projects analyzed in scientific publications. The results show that bio-power and/or heat (bio-P&H) is highly efficient (689 kg CO2e/t dry CR) and economical (269 $/t CO2e) in reducing GHG emissions, but liquid biofuels is not encouraged because of its inefficient performance. Plant size and feedstock collection radius significantly affected GHG reductions of bio-P&H and liquid biofuel. Recommended plant sizes and feedstock types for CRB production were identified from environmental and economic perspectives. Overall, these results clarify the patterns and driving factors of GHG reduction efficiency and abatement costs of various CRB products, providing a framework for optimizing CRB development to combat climate change.