Debunking fears about CO2 Storage

Almost 40-45 Million Tonne of CO2 is being captured and geologically stored every year. By 2050, Carbon Capture and Storage (CCS) could be storing 10-30 billion tonnes of CO2 a year.

CCS captures CO2 from industrial facilities like Steel, Cement, Refineries, Power Plants and then CO2 is injected for permanent storage deep below the Earth’s surface. CO2 is injected deep below earth's surface considering no interference of any means by future societies.But doubts persist, like:

1. What will happen if stored CO2 gets leaked into atmosphere by whatsoever reason? Although CO2 is not poisonous, but at high concentrations CO2 can cause suffocation.
2. What if CO2 finds its way into underground sources of drinking water and contaminate the drinking water?

Proper Site selection is the answer for safe storage of CO2 below earth’s surface.? For a well-selected, well-designed and well-managed geological storage site risks of CO2 leakage are very low. CO2?can be effectively trapped for millions of years, and properly selected sites/ stores are likely to retain injected CO2?for over 1000 years. CO2 is stored much below drinking water table and with a proper seal in place, possibility of CO2 moving up is very remote.

?

Let’s look into the mechanism on how CO2 is stored/ trapped below the Earth’s surface -

CO2 is put inside solid rocks, into tiny pores between the grains of the rocks. CO2 storage Trapping Mechanism is about CO2 and rock interactions in porous media, mainly consisting of CO2?absorption, mineral dissolution, solution trapping, capillary trapping, rock heterogeneity, and physical adsorption.

1.????? Physical trapping - Storage formation bounded by impermeable layers.

2.????? Residual phase trapping - CO2 trapped in tiny pore spaces, as a residual non-wetting phase

3.????? Solubility trapping - CO2 dissolves into the fluid phase

4.????? Mineral trapping - CO2 reacts with minerals in the formation to become part of the solid mineral matrix. The?mineral trapping?of CO2?occurs because of the precipitation of carbonate minerals formed by the combination of dissolved CO2?with metal cations (predominantly Ca, Fe, and Mg).?

Along with site selection, careful and rigorous monitoring of the storage site in necessary for:

1. Verifying the amount of CO2?being put into underground storage.
2. Understanding how the CO2?is behaving once underground.
3. Providing early warning if things are not going as planned.
4. Providing assurance of long-term storage integrity
5. Measuring any leakage that might occur.

?

Generally, CO2?storage sites shall be located to be away from seismic (earthquake) activity and active faults.?However, if a site is well understood, even an earthquake in close proximity to a CO2?storage site shall not result in leakage.

In October 2004, the?Nagaoka CO2?storage and monitoring project?in Japan had experienced a large earthquake during a CO2?injection trial. CO2 injection was stopped immediately, and the site was monitored for possible CO2?leakage. However, no leakage was detected and within next couple of months, CO2 injection was re-started and approx. 10,405 tonnes of CO2?was safely stored.

To contain global warming to 1.5 degrees, we will need to capture and store between 350 and 1200 billion tonnes of CO2 this century. Considering the quantum of present CO2 emissions and future emissions due to continued industrial growth, CCS is an option which can ensure CO2 reduction in VOLUMES.

Options for Geological Storage of CO2.

--xx--xx--