It has been demonstrated that CO2 storage in depleted natural gas reservoirs at gas hydrate formation conditions is an opportunity to mitigate the emission of CO2 from fossil fuel combustion or gasification sources. More than 100 depleted natural gas reservoirs located in Alberta, Canada were investigated and recognized as potential sites for CO2 storage using hydrate technology. Treated flue gas captured from large stationary sources is generally a gas mixture of CO2 with N-2, O-2, and other impurities. The depleted gas reservoirs still contain natural gas that was not economically recoverable. In this work CO2 and a CO2/N-2 (90/10 mol%) gas mixture were used for injection in a laboratory reservoir that contained residual CH4. The experimental results indicated that about 80 % of the original water in the reservoir formed CO2 hydrate after 120 h. The total CO2 storage density (in hydrate, gaseous, and dissolved state) from the injection of the CO2/N-2 mixture into a 500 kPa CH4 reservoir was found to be 118.6 kg/m(3). The addition of a certain amount of tapioca starch in the reservoir delayed the onset of nucleation and improved the CO2 storage density (121 kg/m(3)). This storage density may also be achieved by compressing the gaseousCO(2)/N-2 mixture to 5220 kPa at 285 K. This study shows that hydrate technology provides more CO2 storage density than other storage methods or the same storage but at much lower compression costs.