Geological sequestration is a key part of reducing the rise in global temperature to 1.5°C. By durably storing CO₂ that’s been captured at industrial facilities or removed from the air deep into underground geological formations, sequestration provides a method to securely store gigatonnes of carbon and help achieve net-zero emissions.

We can do this by using engineered Class VI wells that are made from steel and cement and approved by the United States’ Environmental Protection Agency or appropriate state agency. We also enhance safety and efficacy by only engaging in sequestration operations in suitable geographies. While the capacity for CO₂ storage on our planet is huge–more on that later–there are only certain suitable locations for this activity.

That means we either have to pipe in the CO₂ from industrial facilities (such as power plants and cement factories) or build Direct Air Capture (DAC) facilities at those sequestration sites. DAC facilities, like STRATOS, remove CO₂ from the air by pulling ambient air into the facility and through a series of processes, separate and concentrate the CO₂. From that point, it can either be used as a feedstock for carbon products or or sequestered thousands of feet underground using Class VI wells.

Sequestration and DAC are poised to help reduce the amount of carbon in the air at a massive scale. STRATOS alone is designed to capture and store up to 500,000 tonnes of CO₂ per year once fully operational. While it may seem like that’s enough to get the job done, the amount of CO₂ we need to sequester deep underground to curb rising temperatures is on the scale of gigatonnes.

The good news is we have the space and technology to do it. 

Let’s demystify geologic sequestration

While sequestration has gained greater attention in recent years, the process underlying this type of carbon storage has been in use since the 1970s. At the time, companies operating in the Permian Basin of West Texas and New Mexico knew that oil stopped flowing once the wells were about 30% depleted. This meant valuable resources were being left underground.

Through a process known as Enhanced Oil Recovery (EOR), engineers would inject CO₂ into these near-depleted wells to draw out the remaining oil. In this process the CO₂ displaces the trapped oil, allowing the oil to flow while trapping the CO₂ in its place. While there are other EOR processes that use different techniques, the time-tested method of injecting CO₂ into the ground has become the key to enabling carbon sequestration. 

1PointFive’s parent company, Oxy, has been doing EOR for decades, and it has proven to be a safe and secure way to store CO₂ underground. Once there, the CO₂ gets trapped deep below the surface in the rock and can bind to other minerals that naturally exist at those depths. 

All of this is to say that geologic sequestration has been proven to be safe for decades and that once the CO₂ is underground, it typically gets trapped by some of the same geological mechanisms that trapped the oil there in the first place. 

The best places for geological sequestration include depleted oil and gas reservoirs (as mentioned earlier) and saline and basalt formations. The trapping mechanisms for all of these locations are what allow for secure and safe geologic sequestration, which is partly why sequestration-based carbon dioxide removal credits (CDRs) are particularly valuable on the carbon market. 

What are the key advantages of geologic sequestration and storage?

Geologic sequestration has some key advantages in helping to achieve climate goals. First, the high durability addressed above. The more we can do this at a massive scale, the more we will be able to help mitigate the effects of climate change.

Second, our knowledge and experience with this activity. Though geologic sequestration might sound like science fiction, it’s a well-engineered and proven method. It has a minimal footprint on the surface as all that is needed is a wellhead with some small monitors attached.

Third, there is already a vast network of experts, tools, materials and manpower we're familiar with to make transporting and sequestering CO₂ safe, secure and efficient at a massive scale. All we need to do is continue to develop the infrastructure that supports these geologic sequestration projects.

Just how much CO₂ can we store?

The big question: just how much CO₂ could we actually store?

If you want to do the math, here’s the equation from Indiana University: 

SC = h_n * ø_n * ρ_CO2 * ξ

where SC = CO₂ storage capacity in metric tons per unit of area; h_n = net thickness (ft); ø_n = net average porosity (dimensionless); ρ_CO2 = CO₂ density (roughly 47 lb/ft³); and ξ = storage efficiency (ξ =0.1 or 10%, figure 4), which is estimated by multiplying a combination of volumetric and reservoir performance parameters that reflect what portion of the subsurface will actually be occupied by carbon dioxide and how that CO₂ will move through the reservoir. The volumetric portion of ξ includes three factors: net area to total area (area in the basin that has a suitable formation for injection), net thickness to gross thickness, and effective porosity to total porosity.

But if you want the answer in simpler terms, and according to the International Energy Agency, we can globally store between 8,000 to 55,000 gigatonnes worth of CO₂, which is far more than we need to achieve 2050 climate targets.

Achieving this attainable goal requires scaling DAC and expanding carbon capture projects at industrial facilities that can capture CO₂ to be stored underground. As mentioned above, STRATOS alone is designed to capture up to 500,000 tonnes of CO₂ per year once fully operational. Imagine if there were a hundred more similar facilities. That could begin to have an impact on our ability to reduce rising global temperatures.

Constantly perfecting the process

While there’s still work to be done, substantial progress has been made in advancing DAC and Carbon Capture Utilization and Storage (CCUS) as solutions for reducing our carbon footprint and emissions. Countries all over the world have adopted aggressive climate policies that include DAC and CCUS. As more countries adopt these technologies, the availability of suitable land increases. 

Moreover, as the carbon markets mature, more companies begin to enter with products and services built to help the CCUS process. As the Global CCS institute stated, early adopters of CCUS had full vertical integration models, where they were responsible for everything from the DAC to the pipes to the storage and sequestration itself. Now, more third parties are becoming involved, helping to divide responsibilities and decrease barriers to entry. 

Instead of one startup needing the capital to vertically integrate every part of CCUS, they now only need the capital and model to support a portion of it. This provides for more economic diversity and opportunities and affordable supply at an industrial scale. 

With more countries and corporations seeking to join in on the carbon markets, the importance of collaboration and knowledge sharing increases every year. It is especially critical for fast-track development of these technologies and businesses.

Establishing a robust and mature carbon removal industry also creates a wealth of job opportunities. As mentioned, the market is becoming more opportunistic and has fewer barriers to entry, which allows more startups and entrepreneurs to enter it and drive revenue and job growth by partnering with companies across the CCUS value chain. 

For existing companies, taking advantage of tax incentives around CCUS and DAC CDRs is critical to advancing their financial, compliance, and ESG performance and also helps them live up to brand promises with both regulators and customers.

Wrapping it up: what we’ve learned

We’ve reviewed what sequestration is, how it works and addressed its distinct advantages. We’ve also discussed the current progress being made in advancing the technologies, businesses and infrastructure needed to scale the solutions for maximum impact. 

That’s what we’re looking forward to the most with our first sequestration facility: making a difference.