Carbon Management Technology Pathways for Reaching a U.S. Economy-Wide Net-Zero Emissions Goal

The Carbon Management Study Group of the 37^th Energy Modeling Forum (EMF 37) designed seven scenarios to explore the role of three potentially key technology suites - point source carbon dioxide capture and storage (PSCCS), direct air capture of carbon dioxide (DACCS), and hydrogen systems (H₂) - in shaping the broader technology pathways to reaching net-zero carbon dioxide (CO₂) emissions in United States by 2050. Each scenario was run by up to 13 models participating in the EMF 37 study. Results show that carbon dioxide removal technologies were consistently a major part of successful pathways to net-zero U.S. CO₂ emissions in 2050. Achieving this net-zero CO₂ goal without any form of carbon dioxide capture and storage was found to be impossible for most models; some models also found it impossible to reach net-zero without DACCS. The marginal cost of achieving net-zero CO₂ emissions in 2050 was between two and 10 times higher without PSCCS and/or DACCS available. The carbon price at which DACCS was deployed as a backstop technology depended upon the assumed cost at which DACCS was available at scale. Carbon prices were between $250 and $500 per ton CO₂ when DACCS deployed as a backstop. The average CO₂ capture rate across all models in 2050 in the central net-zero scenario was 1.3 GtCO₂/year, which implies a substantial upscaling of capacity to move and store CO₂. Hydrogen sensitivity scenarios showed that H₂ typically constituted a relatively small share of the overall U.S. energy system; however, H₂ deployed in applications that are considered hard to decarbonize, facilitating transition towards net-zero emissions.