Uses and limits of national decarbonization scenarios to inform net-zero transitions

Abstract

Decarbonization scenario ensembles are increasingly used for policy design, company strategy, and stakeholder engagement. However, the limitations of these scenarios may not be adequately understood. We summarize the uses and challenges with applying decarbonization scenarios to inform policy and planning decisions by using a novel database of U.S. net-zero CO₂ emissions scenarios. Models agree that power sector emissions reductions, wind and solar deployment, end-use electrification, energy efficiency, and carbon removal help to reach economy-wide net-zero emissions; however, there is considerable variation in these changes, which may not be reflected in current third-party guidance or international pledges. We show how there is more regional variation in decarbonization pathways than national modeling indicates. The analysis also compares U.S. national scenarios with corresponding U.S. results from global models and finds that models can vary widely in their sectoral emissions reductions, use of carbon removal, and renewables deployment.