About

C-NEMS: An Open, Community-Built Energy Model

C-NEMS is a continuation of Project BlueSky, an effort to build the next-generation energy-economy modeling framework at the U.S. Energy Information Administration (EIA). When federal project activity paused, a group of former EIA staff and partners came together to carry it forward as a fully open-source project, built by and for the modeling community. We believe this work is too valuable to lose.

The energy modeling landscape is already crowded, and that’s a good thing. Different models, built on different mathematical foundations, help us understand the range of ways the future might unfold. No single model or approach has a monopoly on the truth.

What sets C-NEMS apart is its modular design. Most energy models compel every sector into a single mathematical structure. EIA’s National Energy Modeling System (NEMS) does not, and instead lets each sector be modeled using the logic that best reflects real-world market dynamics. We are adapting that modular framework to be more flexible and nimble, so it can keep pace with questions about a rapidly changing energy system. Its structure can evolve along with the questions being asked.

Open code is only half of what makes a model usable. Energy models are data intensive, and the work of turning raw public data into model-ready inputs is where transparency most often breaks down, in undocumented scripts, manual steps, and workflows only their authors can follow. A substantial part of this project is building that layer properly: documented, automated pipelines that map raw data to model input files, so that anyone can trace a result back to its source and reproduce a run from scratch.

Why an independent project

EIA has an ongoing responsibility to deliver data and analytic products on a regular schedule, which limits the agency’s ability to work on higher-risk projects. Operating outside that constraint, we can take bigger swings. We are testing creative mathematical formulations that could cut model run times dramatically, which would let researchers explore a much larger range of possible energy futures. We’re also building the model to take on emerging questions, like the effect of data center demand on energy markets.

Working in the open is part of the same bet. Ideas this ambitious should be exposed to scrutiny early, where the community can weigh in while the design is still taking shape.

Where things stand

C-NEMS is in active development, and we are building it module by module rather than waiting for a single finished release. Each module goes to work on real analytic questions as it is completed. Electricity and natural gas modules are currently under development.

Get involved

C-NEMS is an open-source project. Follow our progress here, contribute to our GitHub repositories, and reach out to info@c-nems.org if you’d like to be part of shaping where it goes next.