Diving deep into underground storage
February 29, 2024
February 29, 2024

Diving deep into underground storage

Read our Whitepaper → Permanent CO2 Storage for Direct Air Capture

We know from escalating climate impacts around the world, our atmosphere is a terrible place to store excess CO2. Heirloom is in the business of removing that carbon and storing it safely and permanently so that it can’t keep contributing to climate-induced disasters.

So if not in the atmosphere, then where?

For now, we’re durably storing CO2 in concrete, however there simply isn’t enough concrete in the world (and there is a lot of concrete in the world!) to account for the billions of tons of CO2 we need to remove from the atmosphere in the coming years.

We need a storage option that is permanent, secure, and large enough to account for billions of tons of CO2. The solution to our problems above ground, lies underground. Geologic storage, which is using wells to place CO2 thousands of feet beneath the Earth’s surface, satisfies all of these requirements.

[As a side note — we often get asked if we can ‘use’ the CO2 we capture. While some removed atmospheric CO2 is currently being transformed or incorporated into products like plastics or jet fuel — these products don’t have lifespans of 1000 years. Heirloom believes that keeping CO2 out of the atmosphere for more than 1000 years is crucial to carbon removal’s ability to be a valuable tool in the world’s long-term climate change mitigation strategy.]

Storing CO2 underground, or geologically, has been safely practiced for decades and is well understood by industry and regulators. But for many outside of those circles, this process is less familiar. To enhance understanding about geological storage, we’ve published an analysis of academic literature on the topic (which you can read here: Permanent CO2 Storage for Direct Air Capture), which explains why geological storage is among the safest places available to permanently store CO2.

Geologic storage can happen through different mechanisms that occur over different time periods, but what is consistent across these pathways is the ability to hold CO2 for tens of thousands of years without interruption. We present a summary on Monitoring, Reporting, and Verification (MRV) best practices, as well as safety and risk management issues for geological storage.  

The most common concern expressed around geological storage is the risk of leakage. Leaks are very rare, and are usually associated with CO2 transportation by pipeline, rather than with geological storage itself [1]. Also, facilities like Heirloom’s pull CO2 directly from the atmosphere and can be located near or even next to the well-head, which means we won’t need to transport CO2 very far.

In the US, the Environmental Protection Agency has rigorous safety standards that they enforce from permitting to decommissioning of wells for geological storage, known as Class VI standards. These govern everything from construction, operating requirements, as well as plugging and testing and monitoring requirements, amongst other things. Heirloom will partner with Class VI operators to ensure that our CO2 is stored in wells that adhere to the highest safety standards. And once Heirloom’s CO2 is sequestered underground, it remains locked up for at least 1000+ years, eventually becoming a solid mineral.

Geological storage is crucial for carbon removal technologies like DAC to make a lasting impact on the climate problem. While very few Class VI wells are yet to come online, the good news is that there’s more than enough space underground to account for all the CO2 humans have emitted to date – meaning we can do more than halt climate change, one day, we can reverse it.

Postscript: If you want to read more generally about our commitment to responsible carbon removal, you can read about our principles here.

[1] J. Alcalde, S. Flude, M. Wilkinson, G. Johnson, K. Edlmann, C. E. Bond, V. Scott, S. M. V. Gilfillan, X. Ogaya, and R. S. Haszeldine, "Estimating geological CO2 storage security to deliver on climate mitigation," Nat. Commun., vol. 9, Article no. 2201, Jun. 2018. [Online]. Available: https://www.nature.com/articles/s41467-018-04423-1