New indicator for comparing the energy performance of CO₂ utilization concepts

CO₂ utilization is increasingly considered a greenhouse gas abatement strategy alternatively to CO₂ storage. Existing indicators that assess the performance of CO₂ utilization options often provide an incomplete perspective and are unsuitable to compare different utilization options with different functionality (e.g. plastics and fuels). This study introduces a new performance indicator for CO₂ utilization options: Specific Primary Energy Consumption per unit of Fossil feedstock Replaced (SPECFER). This indicator, expressed in MJ/MJ, provides a proxy for the energy efficiency of which CO₂ conversion options can replace fossil feedstock required in conventional processes. Three CO₂ utilization case studies (CO₂ based methanol, polyols and dimethyl ether) are used to show the application and effectiveness of the SPECFER indicator. Among the case studies, only CO₂ conversion into polyol appears particularly efficient (SPECFER of 0.05 MJ/MJ), while the other options are not (SPECFER of > 1 MJ/MJ). The paper shows that the SPECFER indicator adds key insights compared to conventional indicators to the effectiveness of CO₂ utilization options and is a promising indicator complementary to CO₂ emissions reduction or life cycle greenhouse gas reduction potential. The SPECFER thus improves the understanding of the performance of CO₂ utilization and enables the possibility to distinctly compare different CO₂ converting utilization technologies.