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Geologic Sequestration of Carbon Dioxide: What You Should Know

November 14, 2022 Welcome

Carbon dioxide released from both natural biochemical processes and human activities is a heat-retaining gas with implications for global warming. Various carbon sequestration technologies are being implemented globally to reduce the levels of heat-trapping carbon emissions. In this article, we will cover geologic carbon sequestration and its risks.

What Is Geologic Carbon Sequestration?

Geologic sequestration refers to the capture and storage of carbon dioxide within naturally occurring rock formations. In this carbon storage technique, large quantities of carbon gas generated from industrial activities such as energy generation and manufacturing are redirected into subterranean geologic formations rather than released into the environment.

Biological vs. Technological vs. Geological Carbon Sequestration

In addition to geologic carbon sequestration, other carbon removal techniques include biological and technological sequestration. This section will highlight how these three sequestration techniques compare to one another.

Biological Sequestration

Biological carbon sequestration is a process mediated entirely by natural processes. Plants, soil, and aquatic bodies capture excess carbon released into the natural environment. For example, about 25% of carbon emissions worldwide are captured and held by green plants and forest trees. Similarly, at least a fourth of the carbon dioxide generated by human activities is absorbed by the world’s oceans.

Plants utilize carbon dioxide emitted by various man-made activities for respiration and photosynthesis. The gas captured by plants can be retained as soil organic carbon and degraded or held within inorganic carbonates for up to 70,000 years.

Technological Sequestration

Carbon capture projects are being implemented to remove heat-trapping CO₂ from the environment. Some of the critical examples of technological carbon sequestration methods include the following:

Carbon-based gas repurposing
Direct air capture plants
Molecule engineering for CO₂ filtration

Gas Repurposing

Carbon dioxide can be repurposed as a substrate for graphene manufacture. This makes it not only is not only effective in reducing gas emissions but also a potentially cost-effective way of creating the material used in various technological devices such as phone screens. There are many additional applications out there today, including beverage industry operations, concrete manufacturing, and chemical plants.

Direct Air Capture

Direct air capture technology is another sequestration technique limiting carbon dioxide emissions. However, at the moment, direct air capture plants are costly to run on a large scale. There is a ton of investment going into this sector and many projects in the horizon. Major industry players include Shell, Oxy, Aramco, Microsoft, and many others.

Molecule Engineering for CO₂ Filtration

Molecule engineering is another frontier in technological carbon sequestration. Scientists have developed specialized molecules that attract and capture carbon dioxide contained in the air. The molecules act as molecular sieves helping to reduce carbon emission levels.

Ideal Sites for Geologic Sequestration

While there are apparent benefits to geological CO₂ sequestration, the intended area for gas injection must be carefully determined. Various screening criteria must be taken into consideration before final selection.

Key factors to consider in site selection for geological carbon sequestration include:

The capacity of the formation
Stability and safety of injection
Compatibility with other chemical compounds already present in the rock formations
The effect on local plant and animal ecosystems
Planned fate for the stored carbon gases

Overall, it is difficult to determine an ideal site for geologic sequestration, and each project must consider prevailing circumstances to make an acceptable choice. It is paramount that site selection takes into consideration how carbon sequestration activities will alter the biochemical and geologic balance in the intended area in the long term.

How Much CO₂ Can the US Store via Geologic Sequestration?

According to a 2013 report by the US Geological Survey, an estimated 3000 metric gigatons of carbon dioxide can be safely stored in geological formations across the US using currently available carbon capture technologies.

Risks and Concerns

While geologic carbon sequestration has the potential to significantly reduce harmful carbon emissions, there are risks associated with the process.

One of the significant concerns with geologic carbon sequestration is gas leakages through faults in rock formations. There is a risk that injected CO₂ can seep through underground drinking water sources and contaminate them. Carbon dioxide leaks from geologic formations into groundwater will cause drops in pH and escalated mineral dissolution rates with the potential release of metal-based contaminants. These events render drinking water harmful and pose a significant health hazard for people using the affected water sources.

Additionally, CO₂ can escape through to the surface and re-enter the atmosphere or overlying buildings, defeating the purpose of sequestration in the first place. There is also the risk of injected carbon dioxide resulting in earthquakes. While this scenario does not happen often, there is a profound risk of rock formations shattering when infused with liquefied carbon dioxide.

IFS Can Support Your Geologic Sequestration Project

At IFS, we work with our customers to provide a custom-made experience suited to their unique process requirements. In addition, we offer a comprehensive range of services to support your CO₂ pumping and geologic sequestration projects.