Clustering direct air capture and low-temperature waste heat sources to optimise the United Kingdom’s future energy system

Direct Air Carbon Capture and Storage extracts carbon dioxide from atmospheric air and enables long-term sequestration. As an innovative Carbon Dioxide Removal method, Direct Air Capture is essential to achieving net-zero per the 2015 Paris Agreement. However, it is highly energy-intensive compared to alternative carbon removal methods, posing challenges for global decarbonisation and energy demand. Limited energy system integration analysis exists for Direct Air Capture, which is crucial to ensure efficient resource allocation in an already-constrained system. This energy intensive technology requires power, heat, and carbon dioxide storage, and the availabilities of such resources in the transforming energy system are limited. In this study, we analyse energy availability for Direct Air Capture in a low-carbon future energy system. We hypothesise that by clustering Direct Air Carbon Capture and Storage installations with low-temperature waste heat from industrial and nuclear power sources, system losses are reduced, minimising energy demand and operational expenses versus a fully electrified solution. This research bridges the gap between development and implementation of waste heat Direct Air Carbon Capture and Storage by calculating available low-temperature waste heat and applying spatial resource analysis of waste-heat clusters and transport to geological carbon storage sites, based on a United Kingdom case study. The study finds sufficient energy resources to meet Direct Air Capture requirements, even in an energy system less reliant on thermal plants. This approach facilitates a 7–13% cost reduction versus the reference case, with positive cost advantages maintained even under a 60% increase in waste heat input costs.