In order to study the effect of impurities, two final cases are included both using identical settings as case 2, Table . Key metrics extracted from Figure for minimum power requirement, minimum CAPEX, and minimum LCOCC and the corresponding liquefaction/pumping pressure at which the minima occurs. Data for case 2 (reference for pure CO 2 , case 9 (post-combustion capture purity), and case 10 (oxy-fuel combustion purity). The observed increase in power for compression with increasing amounts of impurities is in agreement with the findings of Martynov et al. and was explained by the authors to be mainly related to the corresponding decrease in density of the CO 2 mixture as the level of impurities increase, since all the impurities with a significant concentration have a molecular weight lower than that of CO 2 (O 2 , N 2 and Ar). Similarly, Martynov et al. also observed an increase-in the refrigeration power required for liquefaction (at 62 bar) as the level of impurities increase in agreement with the results of the present study explained by the widening of the phase envelope and correspondingly lower temperature required for complete liquefaction (lower bubble point temperature).