An Initial Systems-Level Assessment of Distributed Direct Air Capture at the Urban Scale (UrbanDAC)

Keywords: DAC, CDR, Climate Change, Climate Mitigation, Decarbonization
Abstract Type: Virtual Paper Abstract

Abstract

To address the risks associated with increasing levels of climate change, Direct Air Capture (DAC) systems offer an opportunity to mitigate global carbon emissions by direct carbon dioxide removal (CDR) from the atmosphere. Currently, DAC systems have been conceptualized as large, centralized facilities with relatively high energy demands and specific conditions for siting. Inherent challenges include establishing a sustainable energy source along with the extensive due process, planning, and costs associated with large facilities. Alternatively, distributed small-scale systems have several advantages, such as flexibility and lower costs for uptake (e.g., Distributed Energy Resources). In collaboration with developers of a small-scale DAC unit that adapts to the cooling towers of existing commercial building stock, this study explores systems-level implications of distributed DAC systems in urban areas (UrbanDAC) from a spatial and network perspective. UrbanDAC takes advantage of waste heat and harnesses the adaptability of decentralized systems but presents important issues for cities and regions concerning transportation and storage of captured CO2. We first envision UrbanDAC considering established urban infrastructure systems and their characteristics (e.g., waste removal, rail), then apply a network analysis and spatial multi-decision criteria analysis (MCDA) framework to identify optimal siting of distributed DAC units throughout a mid-sized city in the USA (Knoxville, Tennessee). Our work aims to pilot research for an emerging CDR technology with promising potential toward climate change mitigation goals, but that to our knowledge, carries significant systems-level implications that have not yet been researched.