Buying down the Cost of Direct Air Capture

Abstract

Direct air capture (DAC) shows exceptional promise for carbon dioxide removal on the scale required to fulfill the Paris Agreement. Even though planetary limitations do not constrain the scale of DAC, the currently high cost puts its feasibility in question. By observing cost reduction pathways of similar technologies, this paper explores the cost reduction opportunities that result from learning-by-doing. We developed an analytical buy-down model to investigate what it would take to lower the cost of DAC to $100/ton CO2. Our goal is not to accurately predict future costs, but our analysis demonstrates that if DAC follows a path similar to that of comparable, successful technologies, a capital investment of several hundred million dollars could buy down the cost of DAC. This buy-down effort at a relatively low cost will quantify the learning potential of DAC and show whether its costs can be reduced (like solar photovoltaic modules) or whether despite the investment it remains expensive (like nuclear power generation).

Practical and thermodynamic constraints on electromicrobially accelerated CO2 mineralization

“…Lackner et al. note that while DAC today is unfeasibly expensive ($500 to $600 per tonne of CO 2 ), relatively modest research and development expenditure could put the technology on the cost reduction trajectory that would bring the cost to ≈ $50 per tonne ( Lackner and Azarabadi, 2021 ). Thus, in many of the scenarios we discuss, the total cost of DAC and electromicrobially accelerated CO 2 mineralization could be kept below $100 per tonne.…”

“…The IPCC estimates that by the end of the 21st century, ≈ 20 gigatonnes of CO 2 (GtCO 2 ) will need to be removed from the atmosphere every year to limit global temperature rise to 1.5°C ( Allen et al., 2019 ). In total, it is estimated that between ≈1,000 ( Global Monitoring Laboratory, 2022 ) and 1,500 GtCO 2 ( Keller et al., 2018 ; Lackner and Azarabadi, 2021 ) will need to be removed from the atmosphere to restore it to its pre-industrial state. The US Department of Energy’s Carbon Negative Shot ( Carbon Negative Shot ) sets a target for the removal of gigatonnes of CO 2 from atmosphere at a cost of less than $100 per tonne of CO 2 , a price point thought to be economical by the US National Academy of Sciences ( Committee on Developing a Research Agenda for Carbon Dioxide Removal and Reliable Sequestration, 2019 ).…”

“…The metal ions can then react with CO 2 dissolved in water from the atmosphere to form extremely long-lived carbonate minerals (Power et al, 2013a). For example, peridotite reservoirs across the globe (largely containing olivine) have the potential to mineralize and sequester 10 5 -10 8 GtCO 2 (Kelemen et al, 2019), between 100 and 100,000 3 the excess CO 2 in the atmosphere (z1,000 to 1,500 GtCO 2 ) (Global Monitoring Laboratory, 2022; Lackner and Azarabadi, 2021). Natural weathering (where the breakdown of the mineral occurs However, the world's growing (Prosekov and Ivanova, 2018) and increasingly wealthy population (Hawksworth and Chan, 2015) are creating a growing need for arable land (Tilman et al, 2011), tightening the world's biomass supply (Slade et al, 2014).…”

Current status and pillars of direct air capture technologies

“…Current cost of CO₂ removal using DAC is between $200-$600/ton, which is far from the desired cost target. Lackner and Azarabadi explain that with a capital investment of several hundred million dollars could buy down the cost of DAC as $100/ton ( Lackner and Azarabadi, 2021 ). Mass manufacture of DAC units to increase in number rather than the size of units are thought to lower the cost.…”

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

“…This suggests that the long-term policy goal, in the United States, of $100 t-CO2 -1 may be challenging, yet not impossible, to surpass. 62,63 The technology with the highest cost at scale is the electrochemical KOH BPMED due to its high electricity requirement of 22 GJ t-CO2 -1 . However, alternative electrochemical technologies have the potential to reduce this requirement.…”