(703f) A Tool for the Comparative Analysis of Carbon Dioxide Removal Pathways Via Consistent Life Cycle Greenhouse Gas and Techno-Economic Assessments

For IPCC scenarios that limit global warming to 2°C by 2100 with limited or no overshoot, carbon dioxide removal (CDR) is typically deployed at several gigatons annually over the century. CDR refers to diverse technologies and natural pathways aimed at achieving net CO₂ drawdown from the atmosphere, on a life cycle basis, and sequestration in a durable carbon pool. These pathways can be further categorized as direct air capture of CO₂ and storage (DACCS), afforestation-reforestation-restoration (ARR), marine-based CDR (mCDR), enhanced rock weathering (ERW), and biomass carbon removal and storage (BiCRS). These CDR pathways have been evaluated in the literature; however, inconsistent emissions and economic assumptions, methodologies, and system boundaries make it challenging to generate consistent comparisons between CDR pathways.

In this study, we perform comprehensive life cycle greenhouse gas and techno-economic assessment of several CDR pathways including DACCS, ARR, mCDR, ERW and BiCRS with a cradle-to-grave (CTG) approach, accounting for both direct and indirect emissions and costs associated with the CO₂ captured from the atmosphere all the way to CO₂ long-term storage. By curating data on analysis boundaries, emissions accounting methods, and economic parameters from the literature, we develop a tool to consistently quantify net CO₂ removal, levelized costs of CO₂ removal, and CO₂ removal efficiency. Our assessment addresses key questions regarding the net CO₂ removal and cost-effectiveness of different CDR pathways.