Former U.S. Energy Information Administration (EIA) officials, energy modelers, and partner organizations today announced a new collaborative effort to build the Community National Energy Modeling System (C-NEMS): a free, open-source energy-economy modeling framework.
For decades, EIA has developed and enhanced the National Energy Modeling System (NEMS)—the primary federal model used to project U.S. energy production, consumption, conversion, technology performance, and macroeconomic trends.
Unlike traditional energy models that compel every sector into a single mathematical structure, NEMS allows each energy sector to be modeled using the specific logic that best reflects real-world market dynamics. C-NEMS adapts this modular framework to be more flexible and nimble in addressing questions about a rapidly changing energy system. The C-NEMS team plans to use modules to conduct analysis as they are completed, starting with electricity and natural gas.
C-NEMS originated as Project BlueSky, an EIA initiative from 2022-2025 designed to build a next-generation energy systems model. When EIA paused development, former EIA leaders and research partners decided to continue development of C-NEMS as an independent, open-source community project.
"This work was too valuable to stop," said Joe DeCarolis, cofounder of C-NEMS, former EIA Administrator, and current Department Head of Engineering and Public Policy at Carnegie Mellon University. "Freed from a federal production schedule, we can take bigger swings. For example, we're testing creative mathematical formulations that not only address modern energy issues like data center demand, but could cut model run times dramatically, which would let researchers explore a wider range of energy futures than they can today. We're doing that work in the open, where the community can weigh in."
DeCarolis and former EIA Chief Modeler Sauleh Siddiqui (now a professor at American University) initiated C-NEMS. The project will be guided by a founding advisory board of former energy officials and experts, alongside contributing modelers from Carnegie Mellon University, American University, Ohio State University, Catalyst Cooperative, and Western Spark. Arnold Ventures and the William + Flora Hewlett Foundation support current development.
The team builds C-NEMS in the open and invites researchers, developers, and modelers to contribute to the code repository, follow progress, or collaborate at c-nems.org .
About C-NEMS
The Community National Energy Modeling System (C-NEMS) is an open-source, community-built energy-economy modeling framework. Continuing the foundational work of EIA's Project BlueSky , C-NEMS provides modular, transparent, and freely accessible modeling code and data to advance energy systems analysis. Current development is supported by Arnold Ventures and the William + Flora Hewlett Foundation.
