With a nominal CO 2 capture capacity of up to 36,000 tonnes per year when fully operational, Mammoth located in Iceland is a key milestone on Climeworks’ ambitious scale-up plan of reaching multi-megaton capacity in the 2030s and gigaton capacity by 2050.
Preparations for in-situ CO 2 storage underway, thanks to partner Carbfix Mammoth’s ground breaking took place in June 2022, and the cladding of the process hall and first foundations for the collector containers and maintenance hall were completed end of that year. 2023 kicked off with the start of the CO 2 collector container production.
The construction continues to follow an ambitious timeline and is making steady progress considering current challenges in global supply chains. Now that the harsh Icelandic winter has passed, the company has shared that a further key piece of the facility is about to be completed: the infrastructure for the in-situ storage, owned and operated by Carbfix. This involves the creation of boreholes (narrow shafts vertically inserted into the basalt ground) that will carry the CO 2 that Mammoth captures underground for mineralisation in basalt. Housing these boreholes will be igloo-like structures, foreseen for later this year. The combination of borehole plus housing, is referred to as an “injection well”.
With these two on-site injection wells, Mammoth’s design differs from Orca’s. At Orca, the world’s first commercial DAC+S plant, the CO 2 is carried via pipeline to one single Carbfix injection well several hundred metres away. The ongoing development of the Mammoth project represents a challenging industrial project build, however, by leveraging the company’s field experience and learnings from Orca, the company is able to optimise the execution of the project and integration with a storage solution: Mammoth’s two in-situ injection wells are located less than 100m from the process hall. This makes for an even more efficient delivery of the air-captured CO 2 to Carbfix for permanent storage.
Carbfix: natural and permanent
Carbfix permanently stores CO 2 thanks to its rapid underground mineralisation approach: CO 2 is dissolved in water and stored deep underground in basalt rock formations that accelerate the natural mineralisation process. As a result, the CO 2 turns into stone in less than two years. Climeworks focuses on the permanent removal of CO 2 , and Carbfix’s mineralisation enables just that. Carbfix’s method is one that their expert team has fine-tuned over the last decade and is an accelerated natural process which is fully measurable and permanent for millennia.
Geological storage of CO 2
Mineralisation as done by Carbfix is a specific form of geological storage. Geological storage deep underground is considered a highly robust option for storing CO 2 as it combines technical maturity, permanence, and scalability. This is regardless of whether the storage is based on mineralisation relying on injection of water-dissolved CO 2 (e.g., Carbfix) or conventional storage in which pure-phase CO 2 is stored underground, for example, in saline aquifers. Scientific estimates show that the global potential for geological storage of CO 2 outweighs all greenhouse gases ever emitted since the Industrial Revolution, approximately by at least a factor of three (CDR Primer).
Suitable sites for geological storage exist around the world. They typically include a porous and permeable reservoir rock that serves as the storage location for the CO 2 as well as an impermeable caprock above it, which safely locks the CO 2 underground.
As Climeworks scales and expands internationally, it is exploring further suitable locations for DAC combined with highly durable geological storage, including the U.S, the Middle East, and elsewhere in Europe.