The prospects of massively scalable nuclear-powered direct air capture as a climate solution

Abstract

Direct air capture (DAC) has recently emerged as a promising and scalable solution for removing accumulated CO₂ in the atmosphere to mitigate global warming. Because DAC needs to capture CO₂ from highly diluted levels in the air, it has considerably higher energy demands than conventional CO₂ capture from concentrated industrial sources, making cheap input energy essential. The present study proposes that DAC facilities be powered by dedicated large-scale nuclear power plants designed to deliver the optimal heat/electricity ratio to a DAC unit serving as the condenser in the Rankine power cycle. Such plants are unbound by proximity requirements to CO₂ point sources or electricity demand centres and can be built where nuclear reactors are cheapest to construct, strongly improving the business case. A bottom-up techno-economic assessment and uncertainty quantification study for the year 2050 showed median and 90 % confidence intervals of the levelized cost of removed CO₂ to be 101.6 (71.3–153.9) $/ton when conventional nuclear reactor technology is used. An advanced configuration employing emerging high-temperature nuclear reactor technology to generate excess electricity for co-production of green methanol was slightly more expensive with a larger uncertainty range: 108.0 (68.8–176.1) $/ton. Despite the uncertainty in the assessment, the calculated CO₂ removal costs are attractive compared to projected CO₂ prices in climate change mitigation scenarios targeting substantial emissions reductions by mid-century. However, several non-economic challenges were identified and further work on these topics is recommended to clarify the long-term potential of nuclear-DAC technology as a leading climate change solution.