Seeking the Low-Carbon Route of Methanol Production with Sustainable Resources by Tracking Energy and Environment Indicators

Methanol production is a CO₂-intensive process as its raw materials are mainly from fossil resources. Despite numerous proposed measures for CO₂ mitigation, selecting low-carbon options for methanol production still poses significant challenges. Here, we present an assessment approach based on their fossil energy demand (FED) and global warming potential (GWP). Specifically, four methanol production routes were first established based on the calcium looping sorption enhancement process, namely, coal to methanol, natural gas to methanol, biomass to methanol, and biomass to methanol with biochar (BTMC). Results show that appealing performances for FED and GWP of −17.085 MJ/kg-methanol and −2.457 kg-CO₂-eq/kg-methanol were achieved in the BTMC process. Additionally, by tracking FED and GWP indicators, the lowest carbon footprint route (−5.793 kg-CO₂-eq/kg-methanol) can be quickly identified when considering CO₂ capture, renewable energy, and feedstock substitution for existing processes. Overall, this work provides a new pathway for sustainable methanol production by evaluating low-carbon options from both energy and environmental perspective.