Environmental assessment of emerging carbon capture and utilization technologies

Carbon capture and utilization technologies promise to reduce greenhouse gas emissions and abiotic resource depletion while contributing to a circular economy. However, the environmental benefits of carbon capture and utilization technologies need to be proven. Life cycle assessment is the most applied method when it comes to the evaluation of environmental impacts. Previous life cycle assessments are limited in three aspects. First, previous studies lack in consistently considering the environmental impacts of carbon capture and utilization technologies. Second, the research to date has not been able to provide decision support on whether to introduce carbon capture and utilization technologies in the chemical industry. Third, recent studies failed to prospectively apply a methodological approach for emerging carbon capture and utilization technologies. This dissertation aims to fill these research gaps by the following: first, by applying a systematic literature review accompanied by a metalife cycle assessment; second, by using a change-oriented life cycle assessment in order to provide decision support on how to treat CO2 in the chemical industry; and third, by developing a consistent methodological framework for prospective life cycle assessment and testing this framework with a case study on an emerging carbon capture and utilization technology. One major finding of this dissertation is that the introduction of carbon capture and utilization technologies in the chemical industry can reduce environmental impacts compared to current production practices. Nevertheless, according to the results of the life cycle assessments, priority should be given to promising chemicals. The most promising products investigated in this dissertation are formic acid and dimethyl ether. The CO2-based formic acid production via hydrogenation and dimethyl ether reduces greenhouse gas emissions and abiotic resource depletion regardless of the applied assessment approach, scenario, and electricity supplier. Additionally, the developed framework for prospective life cycle assessment provides guidance to evaluate emerging technologies. The framework is tested by the application to the case study of the electrochemical CO2 reduction to produce formic acid under supercritical conditions. The results of the case study support process engineers on how to further develop the investigated emerging technology.