Diverse Decarbonization Pathways Under Near Cost-Optimal Futures

Abstract

Energy system optimization models offer insights into energy and emissions futures through least-cost optimization. However, real-world energy systems often deviate from deterministic scenarios, highlighting the need for rigorous exploration of uncertainty in macro-energy system modeling. This study uses modeling techniques to generate a diverse array of near cost-optimal net-zero CO2 pathways for the United States’ energy system. Our findings reveal several consistent trends across these pathways, including the rapid expansion of solar and wind power generation, substantial reductions in petroleum use, near elimination of coal combustion, and increased end-use electrification. We also observe varying levels of deployment for natural gas, hydrogen, direct air capture of CO2, and synthetic fuels. Notably, coal with carbon capture and sequestration and synthetic liquid fuels exhibit high adoption rates but only in a limited subset of decarbonization pathways. We uncover interconnected technologies by analyzing technology adoption correlations and energy system interactions. These results demonstrate that diverse pathways for deep decarbonization exist at comparable system-level costs, providing insights into the portfolio of technologies that enable a near cost-optimal net-zero CO2 future.