Direct air capture costs projected higher than previous estimates

Direct air capture costs projected higher than previous estimates
by Robert Schreiber
Zurich, Switzerland (SPX) Mar 11, 2024

In a bold move to combat climate change, Switzerland has committed to reducing its net carbon emissions to zero by 2050, a target that aligns with the global urgency to address the escalating crisis. This ambitious goal necessitates a dramatic decrease in greenhouse gas emissions across all sectors, with a particular focus on mitigating emissions from agriculture and industry-areas where reduction is notoriously challenging.

To bridge this gap, the Swiss climate strategy includes a provision for the active removal and underground storage of 5 million tonnes of CO2 annually. This initiative underscores the nation's proactive stance on climate change, contrasting with the Intergovernmental Panel on Climate Change (IPCC)'s staggering estimate that up to 13 billion tonnes of CO2 will need to be extracted from the atmosphere yearly starting in 2050 to mitigate the worst impacts of global warming.

The linchpin to achieving these climate milestones is the advancement and economic viability of direct air capture (DAC) technologies, which are essential for removing CO2 directly from the atmosphere. Climeworks, an ETH Zurich spin-off, is at the forefront of this technology, operating a facility in Iceland capable of capturing 4,000 tonnes of CO2 annually. However, the cost associated with this technology-between 1,000 and 1,300 dollars per tonne-poses significant challenges to scalability and broader adoption.

A recent study by ETH Zurich researchers has introduced a groundbreaking method for more accurately forecasting the future costs of various DAC technologies. Their findings suggest a significant reduction in costs as technologies scale up, though not to the optimistic figures of 100 to 300 dollars previously cited by some stakeholders. Instead, the research points to a cost range of 230 to 540 dollars per tonne, signaling that while direct air capture will become more affordable, it remains a costly endeavor.

Bjarne Steffen, ETH Professor of Climate Finance and Policy, emphasizes the dual need for rigorous emission reduction efforts alongside the expansion of DAC technologies. "Just because DAC technologies are available, it certainly doesn't mean we can relax our efforts to cut carbon emissions. However, advancing DAC is crucial for tackling emissions that are difficult or impossible to avoid," Steffen notes, highlighting the essential role of these technologies in Switzerland's climate strategy.

The ETH team evaluated three distinct DAC technologies to understand how their costs might evolve. They projected that Climeworks' solid filter technology, which captures CO2 particles using a large surface area filter, could cost between 280 and 580 dollars per tonne by 2050. Similarly, the cost estimates for other DAC technologies, including an aqueous solution of potassium hydroxide and calcium oxide derived from limestone, developed by Canadian company Carbon Engineering and US-based Heirloom Carbon Technologies respectively, indicate a cost range of 230 to 835 dollars per tonne.

One of the key challenges in estimating the future costs of DAC technologies stems from the limited empirical data available, given their relatively recent development and implementation. To overcome this, the ETH researchers conducted a component-based analysis of the different DAC systems, consulting with 30 industry experts to evaluate the design complexity and standardization potential of each component. This approach acknowledges that the cost of simpler, mass-producible components is likely to decrease more significantly than that of complex, system-specific parts. Moreover, the inclusion of mature components, such as compressors, suggests that not all aspects of DAC systems are amenable to cost reductions.

Despite the uncertainties inherent in their projections, the researchers maintain a clear message: the future of DAC technology is still unfolding, and it is imperative to explore all available options. "At present, it is not possible to predict which of the available technologies will prevail. Therefore, it is crucial that we continue to pursue all the options," asserts Katrin Sievert, lead author of the study. This sentiment encapsulates the broader challenge facing global efforts to combat climate change: the path forward is complex and uncertain, requiring a multifaceted approach that combines innovation, policy, and international cooperation to achieve a sustainable future.

Research Report:Considering technology characteristics to project future costs of direct air capture