Numerical Simulation of Diffusion of CO2 Released by Thirty Ships in Mesoscale Deep Ocean

Abstract

Among possible carbon capture and storage methods to mitigate the global warming, the direct injection of CO2 into the deep ocean by the moving ship method, is considered to be a feasible way and expected to minimize its environmental impacts on marine organisms in the vicinity of the injection points. In this study, a simple but effective numerical model for the given practical scenario of very large system was developed with adopting moving and nesting grid technique and low-wavenumber forcing technique. The calculated results show that the maximum change of additional PCO2 is lower than a non-observed effect concentration, +5,000 μatm, in the both small and mesoscale domains. This indicates that the scenario of 30 ships with different length of injection pipes injecting total CO2 of 50 million t/yr and moving in the 110 × 330 km operation area is efficient and effective. The developed techniques demonstrated its efficiencies and applicability to give an outline for the optimization of the CO2 ocean sequestration system, by which biological impacts should be minimized and insignificant.