News & Updates

With momentum building in the carbon removal sector – and all eyes on the anticipated impacts of the Inflation Reduction Act – we’re seeing the world dive deeper into the different ways Direct Air Capture (DAC) can help build a net zero future.

At a glance, there are two main DAC pathways – using a sorbent (i.e., solid) capture material versus using a solvent (i.e., liquid). Nearly a decade-and-a-half ago, Carbon Engineering (CE) made the decision to pursue a liquid solvent approach. Today, one of our most frequently asked questions is: Why liquid?

We’re pleased to see a number of new assessments released by the scientific community over the last year that help evaluate the different DAC technologies. Each brings improved methodology and a greater level of comprehension to compare various approaches. Read about these reports below:

1.  Global Assessment of Direct Air Capture Costs

International Energy Agency Greenhouse Gas R&D Programme (IEAGHG)
DECEMBER 2021

About this report:
This study aims to improve the current Direct Air Carbon Capture and Storage (DACCS) cost-performance evidence base by synthesising data from recent literature and technology developers to explore the economic feasibility of different DACCS technologies (both liquid and solid based systems).

From report conclusion:
“For liquid systems, large-scale plants are significantly more cost-effective due to economies of scale. Solid DACCS costs scale more linearly with size and are likely to be the more cost-effective option for smaller plants (<100ktCO₂/year), with significant potential for cost reduction through innovation. Capex, electricity prices and solid adsorbent costs are found to be the most influential parameters on costs.”

Read the full report here.

2. Direct Air Capture Case Studies

National Energy Technology Laboratory (NETL),
Department of Energy (DOE)

3. The cost of direct air capture and storage; the impact of technological learning, regional diversity, and policy

John Young et al., Research Centre for Carbon Solutions, Heriot-Watt University, Edinburgh
JULY 2022

About this report:
This report aims to answer the question “where are the costs of direct air capture and storage heading, and what influence does siting and policy have?” by estimating ranges for the current and future costs of 2 liquid and 2 solid sorbent direct air capture processes paired with CO₂ transport and storage:

Liquids based:
1.   KOH-Ca looping: Capture using a circulating potassium hydroxide (KOH) solution with sorbent regeneration via ion exchange and calcination. CE uses this liquid solvent-based process*.
2.   KOH BPMED: Capture using a circulating potassium hydroxide solution with sorbent regeneration via bipolar membrane electrodialysis.

Solids based:
3.   Solid Sorbent: Capture using a stationary solid sorbent with cyclic temperature-vacuum swing sorbent regeneration.
4.   MgO ambient weathering: Capture using circulating magnesium oxide (MgO) solids sorbent regeneration via calcination.

From report conclusion:
“For a plant in the United States paired to wind electricity and a heat-pump for low-grade heat where applicable, these first-of-a-kind (FOAK) net removed costs were estimated as i) $230-580 t-CO₂^-1 for KOH-Ca looping*, ii) $690-1230 t-CO₂^-1 for KOH BPMED, iii) $1250-3000 t-CO₂^-1 for solid sorbent, and iv) $260-760 t-CO₂^-1 for MgO ambient weathering.

However, technological learning will drive down the costs as a function of repetition and learning by doing, to an average of several 100’s of dollars per tonne CO₂ net removed. Using technology learning curves, our study forecasted that the costs may reduce, at the Gt-CO₂ year^-1 scale for a plant in the United States paired to wind electricity and a heat-pump for low-grade heat where applicable, to i) $80-410 t-CO₂ ^-1 for KOH-Ca looping*, ii) $240-780 t-CO₂ -1 for KOH BPMED, iii) $100-590 t-CO₂^-1 for solid sorbent, and iv) $80-520 t-CO₂^-1 for MgO ambient weathering.”

Read the full report here.