Liquid CO2 injection for geological storage in deep saline aquifers

► We propose injecting CO2 in liquid state rather than supercritical. ► Liquid CO2 injection is energetically advantageous. ► Liquid CO2 injection requires a smaller compression work at the wellhead. ► Liquid CO2 is denser than SC CO2, inducing a lower overpressure at the aquifer. ► The caprock mechanical stability is improved when injecting cold CO2.