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NEMO: the Next Energy Modeling system for Optimization

NEMO, the Next Energy Modeling system for Optimization, is a high-performance, open-source energy system optimization tool. It is intended for modelers who seek substantial optimization capabilities without the financial burden of proprietary software or the performance bottlenecks of common open-source alternatives.


Last updated on 29 December 2022

NEMO is designed to analyze critical questions in contemporary energy policy – including the grid integration of variable renewable energy, the role of energy storage, and robust planning responses to climate change. It is a full energy system optimization tool that can be run from a command line or with SEI’s Low Emissions Analysis Platform (LEAP) as the user interface. The combination of LEAP and NEMO puts powerful optimization features within reach of planners, energy analysts, and others who are not full-time modelers. NEMO is used for capacity expansion and power development planning, energy strategies, energy-water-food nexus analyses, and deep decarbonization studies.

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
  • Modeling of renewable energy targets
  • Parallel processing
  • Support for multiple solvers, both open-source and commercial
  • Numerous performance tuning options
  • Data stored in an open-source relational database, allowing easy access to inputs and results

NEMO’s source code and documentation are available on the NEMO website. The tool is available free-of-charge for use in command line mode. A separate license, which can be requested on the LEAP website, is required to run NEMO with LEAP. SEI provides free licenses to use NEMO with LEAP to qualified academic, governmental, and nonprofit organizations based in low and middle income countries, as well as to students worldwide. A modest license fee is charged to other users, including consulting companies and utilities.

Meet the team

2018 portrait of Charlie Heaps
Charles Heaps

Energy Modeling Program Director


Eric Kemp-Benedict
Eric Kemp-Benedict

SEI Affiliated Researcher


2018 portrait of jason veysey
Jason Veysey

Senior Scientist


Design and development by Soapbox.