NEMO is a high performance, open-source energy system optimization modeling tool developed in Julia. It is intended for users who seek substantial optimization capabilities without the financial burden of proprietary software or the performance bottlenecks of common open-source alternatives. Key features of NEMO include:

• Least-cost optimization of energy supply and demand
• Support for multiple regions and regional trade
• Modeling of energy storage
• Nodal network simulations and modeling of power and pipeline flow
• Modeling of emissions and emission constraints (including carbon pricing and pollutant externalities)
• Modeling of renewable energy targets
• Support for simulating selected years in a modeling period
• Parallel processing
• Support for multiple solvers: Cbc, CPLEX, GLPK, Gurobi, HiGHS, Mosek, and Xpress
• Optimization warm starts
• SQLite data store
• Numerous performance tuning options

NEMO can be used in command line mode or with the Low Emissions Analysis Platform (LEAP - formerly the Long-range Energy Alternatives Planning system) as a graphical user interface.

Development of NEMO is led by the Energy Modeling Program at the Stockholm Environment Institute (SEI).

For instructions on installing and using NEMO, see the documentation.

If you are interested in contributing to NEMO, please contact Jason Veysey.

NEMO's Julia code is made available under the Apache License, Version 2.0. See LICENSE.md for details, including attribution requirements and limitations on use.

The initial versions of NEMO were informed by version 2017_11_08 of the Open Source Energy Modelling System (OSeMOSYS), which was also released under the Apache License, Version 2.0.