Atmospheric alchemy: The energy and cost dynamics of direct air carbon capture
Authors: Ozkan Mihrimah 
Published: July 2024

Abstract
Amid a relentless global climate crisis, the 28th Conference of the Parties (COP28) spotlighted Direct Air Carbon Capture (DACC) as a key intervention to mitigate escalating temperatures and CO2 levels. The Intergovernmental Panel on Climate Change (IPCC) underscores the urgency of this challenge, stipulating the need for robust CO2 removal strategies. It sets a daunting yet crucial target: capture 85 million metric tons of CO2 by 2030, escalating to 980 million metric tons by 2050, to achieve net-zero emissions (IEA, Executive Summary—Direct Air Capture 2022—Analysis. https://www.iea.org/reports/direct-air-capture-2022/executive-summary). Despite this imperative, the existing 19 operational DAC facilities globally face significant barriers, including prohibitive costs and stringent regulations, which impede their large-scale application (Ozkan et al.). Current status and pillars of direct air capture technologies. Iscience (2022). While COP28 stopped short of delineating a definitive roadmap for DAC, this article addresses a vital aspect of this technology: DAC processes’ substantial energy and heat requirements, which are integral to their operational efficiency and economic viability. This article illuminates pathways for future technological evolution and cost optimization through an in-depth analysis of these requirements, thereby charting a course toward a more effective and scalable DAC infrastructure.

Graphical abstract

Highlights
With atmospheric CO2 exceeding 420 ppm, the clock is ticking on the climate crisis. DAC offers a revolutionary approach to directly remove this excess CO2, acting as a critical tool in our fight for a sustainable future. However, current DAC systems face the challenge of high energy consumption. Continuous fan operation for air intake and sorbent material regeneration, consuming nearly 2000–3000 kWh per ton of CO2 captured, are major contributors. Optimizing these processes is crucial. Advancements in sorbent efficiency, system design that minimizes parasitic energy losses, and seamless integration with renewable energy sources are key to slashing DAC’s energy demands. By reducing its carbon footprint and enhancing economic viability, these advancements can unlock the full potential of DAC to become a game-changer in combating climate change and securing a cleaner future for our planet.

Discussion
Given the significant energy and heat requirements of DACC processes, what technological innovations are necessary to make these systems more energy efficient and economically viable? Considering the substantial energy demands of DACC processes, what are the most promising avenues for reducing these requirements to enhance the technology's scalability and cost-effectiveness? How can current technological limitations be overcome to scale up DACC effectively? What role could renewable energy sources play in meeting the energy and heat demands of DACC facilities, and how might this integration impact the overall carbon footprint of the carbon capture process? How do the energy and heat requirements of DACC technologies influence their location and infrastructure needs, particularly in relation to energy sources and heat sinks? What technological innovations or advancements are currently being explored to optimize the energy and heat efficiency of DACC processes, and what challenges do they face in terms of implementation and scaling? Given the significant role of DACC in achieving net-zero emissions targets, how can policy and regulatory frameworks be designed to support the development and deployment of energy-efficient DACC solutions?