Carbon GeoCapture: A Revolutionary Approach to Carbon Sinks

John Pope, President and CEO, Carbon GeoCapture

To achieve a net-zero emissions economy by mid-century, society would need to capture and sequester five to 12 billion metric tons (gigatons) of carbon dioxide per year over the next 30 years – the equivalent of filling between two to five million Olympic-sized swimming pools with CO₂. Largescale carbon capture, utilization and sequestration (CCUS) can become an important tool for managing carbon emissions from heavy industries, including cement, steel, chemicals and baseload power generation – to name a few.

According to the World Economic Forum (WEF), CCUS has the potential to remove 90-99% of CO₂ emissions from heavyemitting industries. Currently, only carbon sequestration in geologic formations, where most of the carbon dioxide originated, can occur on a scale large enough to meet this need.

Coal as a Carbon Sink

Imagine turning geologic coal formations into carbon sinks. Coal seams that are uneconomic to mine can be used to permanently store captured CO₂. This innovative approach provides a cost-effective and scalable method for achieving the level of CCUS deployment that some international organizations have called for.

To date, various entities have injected approximately 375,000 metric tons of CO₂ into coal seams worldwide. Over the past 30 years, the underlying science of CO₂ sequestration in coal has been extensively investigated, including several studies initiated by the U.S. Department of Energy (DOE). While the technology was successfully implemented and refined, it still lacked the critical breakthrough needed to rapidly scale the solution as promised.

The Overlooked Solution: Mimicking Nature for Safe Carbon Sequestration

Previous efforts to permanently store CO₂ in coalbeds used conventional high pressure, concentrated gas sequestration approaches. That damaged the coal and limited its ability to contain the CO₂. To successfully sequester CO₂ in unmineable coal seams at scale, Carbon GeoCapture has developed a new approach to avoid geological damage and ensure these geologic formations reach their full potential to store CO₂. The scientific advances to make this approach commercially viable entailed 25 years of R&D and fieldwork and $40 million of investment.

We use a gentle, safe sequestration approach that mirrors the one found in nature. It preserves rock integrity and allows careful management of carbon sequestration levels. This approach does not require concentrated, high-pressure streams of carbon dioxide, which allows us to avoid some of the most expensive steps in carbon capture and reduce overall carbon management costs.

We take naturally occurring water from a coal seam, dissolve CO₂ into that water at relatively low pressures and then inject the mixture back into the coal bed. The CO₂ is preferentially adsorbed by the rock’s nanopores as the water flows through it. When the rock is nearly full of carbon dioxide, we allow the naturally occurring water to hold the pressure necessary to keep it in place – as it’s already done for millennia. This process mimics nature to permanently store carbon dioxide in the ground, safely and efficiently.

Coal Seams: Nature’s Carbon Filters for Safe and Cost-Effective CO₂ Storage

Coal seams offer a naturally occurring method of carbon storage. These formations act like carbon filters, preferentially absorbing carbon dioxide and thereby significantly reducing the need and cost of cleaning up flue gas to the purity required by conventional CCUS. Co-injecting carbon dioxide into coal with water also reduces the requirement for high compression of the carbon dioxide, further lowering costs. This method also avoids the issue of coal swelling at the injection site, which hampered prior direct injection approaches.

Sequestering carbon dioxide in an underpressurized coal seam (reservoir) poses lower geological risk, because the seam acts like a sponge, drawing in the lower pressure CO₂ and fixing the carbon in its nanoporous structure, cemented in place by chemical bonds. This contrasts with the “balloon” that is blown up in a saline aquifer, where the pressure in the reservoir is higher than the surrounding rock, and the CO₂ wants to escape and is only held in place by 8,000 feet of caprock – which could crack, subside or experience earthquakes. Thus, the risk of a leak is much lower in a coal seam than in conventional CCS sinks.

Using carbon sinks as coal beds is also cheaper – by as much as 80% – and more efficient than storing CO₂ in conventional reservoirs (like sandstone and carbonate). These cost savings can accrue significantly over time, allowing for more extensive carbon sequestration efforts with fewer resources.

Moreover, many heavy industrial sites have historically been located near coal deposits to allow for more efficient and cost-effective access to coal as an energy source. Today, this same proximity can be leveraged to significantly reduce transportation costs associated with sequestering carbon dioxide. This avoids the need to build pipelines that could span hundreds of miles and cut across several states to reach underground sequestration sites.

Revitalizing Communities Through CO₂ Storage

Many communities and local economies depend on employment in heavy industries. These communities often face economic hardship as the world shifts towards renewable energy sources. Capturing CO₂ emissions and locking them away in coal seams offers an opportunity to revitalize the communities most at risk of being left behind in the energy and industrial transition.

This process can provide opportunities to retain a skilled workforce, creating good jobs in operating carbon storage projects. These communities have the knowledge and skills needed to put CO₂ back in the ground where it came from.

By leveraging the existing expertise and infrastructure of coal-producing regions, CO₂ sequestration projects can offer local communities an economic lifeline. Workers can be trained to inject CO₂ into coal seams, ensuring they remain an integral part of the energy sector. This transition creates jobs and promotes economic stability and growth in regions that might otherwise suffer from the decline of traditional fossil fuel industries.

Additionally, by investing in CO₂ sequestration in coal seams, we can support local economies, protect jobs and contribute to global efforts to mitigate climate change. This method offers a dual benefit: addressing environmental concerns while fostering economic resilience in communities historically dependent on coal.

The Future of Cost-Effective and Safe Carbon Storage

Injecting CO₂ into coal presents the best opportunity within CCUS to reach scale faster and safer and is more economically feasible than conventional CCUS methods. Coal seams are widely available and offer lower associated transportation and operational costs than deeper geologic sequestration options. Their unique ability to act as natural carbon filters minimizes the need for expensive purification processes, making it a cost effective solution.

The lower geological risks associated with coal seams enhance the safety and reliability of long-term carbon storage. By leveraging the existing infrastructure and expertise in coal-producing communities, this approach not only supports economic transition but accelerates the deployment of CCUS at scale.

Additionally, sequestering CO₂ in coal seams process allows for signifi cant reductions in emissions from existing coal-fi red power plants.

Successful implementation of this process to reduce emissions at coal-fi red power plants can drive adoption in major coal- using countries like India and China, which are increasing their use of coal. This process and technology provide a pragmatic solution to significantly reduce emissions from coal power in the near term, ensuring energy reliability, protecting jobs and driving innovation that benefits both the U.S. and the global energy transition.