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Direct air capture

From £533/tonne · Questions? Talk to sales

Overview

Direct air capture (DAC) is a chemical process to capture ambient CO₂ from the atmosphere. Captured CO₂ is then transported and stored underground in disused gas fields or in specific geological formations where it mineralizes in a reaction with the surrounding rocks.

DAC involves five basic steps: 1. Getting large volume of air in contact with sorbents (using huge fans for example) 2. capturing CO₂ with a liquid or solid sorbent 3. regeneration of the sorbent with heat and/or pressure 4. compressing and transporting CO₂ to the storage site 5. injection in geological storage

Steps 1, 3 and 4 all require relatively large amounts of energy, which must mostly be renewable in order to achieve net carbon removal. This is the main downside of DAC.

Locating DAC facilities is therefore dependant on renewable energy abundance, and proximity to the geological formations suitable for storage.

The science

DAC technology can be differentiated by the specific chemical processes used to capture ambient CO₂ from the air and recover it from the sorbent.

The two main options pursued at demonstration scale are:

1. liquid solvents (hydroxides) that require high-temperature for regeneration (800 degC+)

2. solid sorbents (amines) that require lower temperature regeneration (85-120 degC), but more expensive equipment

There are other concepts in development such as regenerating by moisturising of solid sorbents, electro-swings, nano-membranes and even DAC-ERW hybrid approaches using silicate rocks.

Compared to other removal methods, the primary barrier to upscaling DAC is its high cost and large energy requirement.

The duration of storage is an important consideration; geological reservoirs or mineralization result in removal for more than 1000 years, but there is a very small risk of reversal / leakage from geological storage before mineralization takes place.

A key consideration is the net carbon CO₂ removal of DAC over its lifecycle. It mainly depends on the carbon intensity of the energy input and other lifecycle considerations such as construction and equipment.

DAC has no co-benefits apart from innovation and job creation.

Supercritical‘s view

DAC is the only technology that removes CO₂ directly from the ambient air - not via photosynthesis, ocean or soil moisture. As such it holds a special place amongst carbon removal technologies. It requires little land and is not constrained by many factors apart from energy and appropriate underground storage sites.

At the same time the ‘direct from air’ nature also poses great challenges - even though it’s causing us a lot of trouble, CO₂ concentration in the air is only 0.04% - and removing that specific, well ‘diluted’ component of the atmospheric gas mix is not a small task.

We are delighted to see a bit of an arms race in terms of the largest DAC facility opening in the next couple of years.

CO₂ captured with DAC can also be used to make products, including fuels, or be injected as a part of a process called enhanced oil recovery. Our credits strictly prohibit these uses, as we would not count either as true removal. There are links between DAC and the oil industry however, as the injection makes most economic sense where it can use existing fossil fuel extraction infrastructure and equipment.

Bojana Bajzelj

Head of Climate

Our suppliers

Our supplier was founded in Calgary, Canada. Following years of prototyping and technology research and development, they moved to British Columbia to build an operational pilot plant; first capturing CO₂ from the air in 2015.

Our partner licenses their technology to other companies to build operational plants, one of whom has begun work on the world’s first large DAC plant — aiming to remove a million tonnes of CO₂ annually from 2025.

Supercritical holds a contract with our DAC partner to secure price and volume of delivery, and is working to formalise this further with a contract with their licensees.

Project locations 1

  • Map of Texas, USA
    Texas, USA

Verifications

Our climate team ensures only high-quality carbon removal makes it onto the Supercritical marketplace.

Each Project has completed our rigorous 8-point vetting process, with fewer than 6% passing.

Supercritical Vetted Project badge

The Supercritical marketplace only features projects that:

  • Remove carbon

    We do not deal with carbon avoidance or carbon reduction offsets

  • Are net negative

    A project’s removal must be net of lifecycle emissions

  • Are Measured, Reported and Verified

    Projects must have MRV and unique retirement on an established registry

  • Are additional

    The removal must not have occurred in the absence of a market for offset credits

  • Do no significant harm

    Projects must cause no ecological, economic or social harm

  • Have clear permanence

    Permanence must be well established, and be conservative

  • Have co-benefits

    Environmental, social, economical co-benefits

  • Have potential

    Projects must have significant future scaling potential

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