announcing Temoa v4.0!

[Joe DeCarolis]

Dear openmodders,

We are pleased to announce the release of Temoa v4.0! While I have not regularly posted updates here, our team has continued to actively develop the platform. This version represents a substantial step forward, with major architectural improvements, expanded modeling features, and a focus on usability, extensibility, and transparency. This work has been an active collaboration between the Open Energy Outlook, CANOE, MAHTEP, Sutubra Research, and Western Spark.

A few highlights from the release:

License change

Following the lead of PyPSA and oemof, we’ve changed the Temoa license to be more permissive, migrating from GPLv2 to MIT with this release. 

Model documentation

The model documentation is comprehensive and details all of the new functionality outlined below.

Architecture, packaging, and usability
Temoa now includes a comprehensive command line interface for managing runs and configurations. The project has been fully refactored for PyPI compatibility, making installation and environment management much more straightforward. We have also adopted uv for faster dependency resolution and set HiGHS as the default open-source solver.

Modularity and developer experience
The core model structure has been significantly refactored, breaking apart historically monolithic components into cleaner, more maintainable components. This should make it easier for users to understand, extend, and contribute to the codebase. We have also added a network visualization tool to help users explore and debug system structure and flows.

Storage and system flexibility
Version 4 introduces full support for long-duration energy storage, including seasonal storage behavior and inter-season dynamics. Storage modeling has been generalized, and ramping constraints have been redesigned to better reflect operational realities.

Materials, emissions, and lifecycle modeling
We have expanded Temoa to represent material supply chains and waste streams, along with embodied emissions. Lifecycle modeling has also been improved through the introduction of survival curves and more consistent handling of end-of-life and early retirement decisions.

Time representation and commodities
The representation of time has been fully generalized, removing legacy limitations and enabling more flexible temporal configurations. We have also added support for annual commodities and improved handling of efficiency and baseload technologies.

Units checking

Unit validation and checking have been added to Temoa v4.0. Units defined in input tables are automatically propagated to output tables when model results are written; also checks for unit consistency across tables.

Code optimization

Instantiation, solving, and results processing times, along with memory requirements, have all been substantially improved by reducing model redundancies and optimizing code.

Overall, Temoa v4.0 is intended to provide a more robust and flexible foundation for full energy system analysis while remaining open-source and transparent. We hope these updates make the platform more useful to both existing users and those considering adopting it.

We would very much welcome feedback, questions, and collaboration from the community. To help us track and respond effectively, we’re using GitHub Issues as the primary channel for questions, bug reports, and feature discussions.

Finally, if there is interest, the MAHTEP group is organizing a free Temoa workshop June 16-19 in Torino (details here).

Best regards,
Joe DeCarolis, on behalf of the development team

[Mark Howells]

Great stuff Joe and team (!!)

 

From: openmod-i...@googlegroups.com <openmod-i...@googlegroups.com> On Behalf Of Joe DeCarolis
Sent: 14 April 2026 13:02
To: openmod-i...@googlegroups.com
Subject: [openmod-initiative] announcing Temoa v4.0!

 

You don't often get email from jdeca...@gmail.com. Learn why this is important

** THIS MESSAGE ORIGINATED OUTSIDE LOUGHBOROUGH UNIVERSITY **

** Be wary of links or attachments, especially if the email is unsolicited or you don't recognise the sender's email address. **

--
You received this message because you are subscribed to the Google Groups "openmod initiative" group.
To unsubscribe from this group and stop receiving emails from it, send an email to openmod-initiat...@googlegroups.com.
To view this discussion, visit https://groups.google.com/d/msgid/openmod-initiative/CAFyU%2B7tRUo37mrXk2o7A5Zy98qc1DD8n0G917zMHG4qzfBOPdw%40mail.gmail.com.