Durable CO2 Storage: A Key to Effective Carbon Removal

Carbon removal is a critical tool in addressing climate change, but it’s only effective if the captured carbon dioxide (CO2) stays out of the atmosphere for the long term. This requires durable CO2 storage, ensuring that the removed CO2 doesn’t simply cycle back into the air, undoing the benefits of removal.

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What is Durable CO2 Storage?

Durable CO2 storage refers to methods of securely storing captured CO2 so it remains isolated from the atmosphere for centuries to millennia. For carbon removal approaches to be truly impactful, the storage solutions they rely on must demonstrate this long-term permanence.

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Varying Levels of Durability

Not all storage methods are created equal when it comes to permanence:

• Short-term storage options, like in soil or vegetation, may release CO2 back into the atmosphere due to natural processes such as decomposition or land-use changes. It is imperative that solutions that rely on short-term storage are maintained to result in the longest-term storage possible.

• High-permanence storage solutions lock CO2 away for significantly long periods, ensuring its effective removal from the carbon cycle.

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Forms of High-Permanence CO₂ Storage

Several storage methods are recognized for their durability, including:

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Underground Geologic Storage

• Sedimentary Basins: CO2 is injected into deep underground rock formations, where it is locked in the porosity of the sedimentary rocks, and trapped under impermeable layers, preventing its escape. This is similar to how oil and gas it trapped in basins today. 

• Basaltic Reservoirs: In these volcanic rocks, CO2 reacts with minerals to form stable carbonate solids, effectively converting the gas into rock in a process known as mineralization.​