Spatial disparity of life-cycle greenhouse gas emissions from corn straw-based bioenergy production in China

Abstract

Crop straw can be converted into bioenergy through various conversion pathways. Assessing the spatial disparity of greenhouse gas (GHG) emissions under different bioenergy conversion pathways could support region-specific policy decisions. This study assessed GHG emissions of seven corn straw-based bioenergy conversion pathways across 30 provinces in China, using a hybrid life-cycle assessment method based on a multi-regional input–output model. The results showed that, due to spatial disparity of economic supply chains, life-cycle GHG emissions of seven bioenergy conversion pathways clearly differed across 30 provinces and ranged within 82–439 kg CO2-eq per tonne of fresh corn straw with 80% moisture. Most of the bioenergy conversion pathways yielded GHG mitigation benefits across 30 provinces, except for electricity through biogas burning pathway in 3 provinces and bio-natural gas pathway in 28 provinces. Additionally, due to the spatial teleconnection of economic supply chains, bioenergy production occurring in one province could lead to GHG emissions in other provinces. The highest interprovincial embodied GHG emissions primarily occurred in Shandong. In 2012, the maximum GHG mitigation potential from corn straw-based bioenergy using straw burnt in field and abandoned amounted to 253 million tonne CO2-eq in China and interprovincial embodied GHG emissions amounted to 1.8 million tonne CO2-eq in Shandong. The findings support region-specific policymaking in the selection of suitable corn straw-based bioenergy conversion pathways and national policies for the promotion of interprovincial collaboration to reduce bioenergy-related GHG emissions.