Life cycle assessment of emerging coal conversion technologies in China: An industrial-scale comparison

The continued large-scale industrialization of emerging coal conversion technologies (ECCTs) in China is an uncertain factor in the global de-coaling process. Its environmental impact is unclear or underestimated because of a lack of comprehensive and comparable studies. The objective of this study was to comprehensively quantify the environmental impacts of nine industrialized ECCTs in China to promote a shared understanding and facilitate discussion on this topic. A life cycle assessment (LCA) was used for modeling, and industrial added value was incorporated into the LCA model as a comparative benchmark for different ECCTs. The CML2001 method was used to model a localized LCA data inventory for representative projects. The results showed that medium- and low-temperature coal tar hydrogenation, coal to fuel ethanol, coal to ethylene glycol, and coal to olefins yielded lower environmental impacts than other ECCTs, and someone of the former three ECCTs was able to always exhibit the best competitiveness despite fluctuations in the feedstock product prices. The abiotic depletion potential of elements and the global warming potential was intensive in the material supply and feedstock conversion stages, respectively, and the majority of the other environmental impacts were derived from the feedstock and energy supply stages. If no mitigation strategies are implemented, carbon emissions caused by the industrialization of ECCTs may increase from 0.36 Gt CO2-eq at present to 1.02 Gt CO2-eq in 2030. This finding highlights the necessity of mitigating carbon emissions and calls for robust approaches to coordinate energy security and carbon neutrality.