Fulfilling the negative emission effect of hydrothermal CO2 utilization through process optimization and supply chain decarbonization

Abstract

Hydrothermal CO₂ utilization for producing chemical feedstocks offers a promising route toward sustainable development and carbon neutrality. However, the significant energy consumption along with reductant consumption, introduces potential uncertainties in its environmental benefits. An ex-ante life cycle assessment of 12 hydrothermal CO₂ utilization pathways revealed that the carbon footprint of benchmark cases cannot realize carbon reduction effect even when considering captured CO₂ and offsets from converted products. By integrating chemical process simulation and scenario analysis of decarbonized background datasets, the influence of internal process variables and potential supply chain change were comprehensively analyzed. Under the optimal production system design and low-carbon scenario for energy supply, the carbon footprint can reach −0.4129 kg CO₂-eq/kg absorbed CO₂. This research elucidates how internal and external factors influence the environmental outcomes of hydrothermal CO₂ conversion, providing a comprehensive framework for assessing the sustainability of emerging technologies and guiding their development towards minimizing environmental impacts.