Download the National Energy Modeling System (NEMS)
Overview
NEMS is an integrated model of the U.S. energy system. For an overview of NEMS, see The National Energy Modeling System: An Overview 2023. More detailed documentation of NEMS is also available.
The open-source NEMS code allows the public to replicate the Annual Energy Outlook 2025 (AEO2025) results and discloses the source code and inputs used.
NEMS is available on GitHub