In terms of the urgent global challenges of climate change and the increasing concentration of greenhouse gases in the atmosphere (Friedlingstein in Global Carbon Budget, 2023; Lee and Romero in Climate Change 2023: Synthesis Report, 2023), the reduction of CO₂ emissions is the focus of efforts by scientists, politicians and industry representatives worldwide (Davis and Lewis in Net-zero emissions energy systems, 2018). The decomposition of CO₂ by using plasmalysis, in particular microwave assisted plasmalysis, is an innovative process that has attracted significant interest in recent years as it is potentially more efficient and environmentally friendly than traditional methods (Silva et al. in Study of CO2 Decomposition in Microwave Discharges by Optical Diagnostic Methods, 2016; Ong et al. in Journal of cleaner production 336, 2022; Zhang and Zhang in Environmental Science and Technology, 2021). For the evaluation of the plasmalysis process, the specific energy input SEI and the energy efficiency η among other key values are typically used (Fridman in Plasma Chemistry, 2008). This paper introduces two new key numbers to these indicators, the global energy input GEI and the global energy efficiency γ. With the help of these two indicators, parameter dependencies of the plasmalysis process can be better understood in the future, and optimization potentials can be better uncovered. This also makes it easier to compare different plasmalysis processes with each other. Various parameters such as microwave power, gas flow rate, and pressure are systematically varied in order to investigate their influence on the GEI.