TransitionZero's open source translator becomes a core part of the Linux Foundation's new OpenGrid initiative

London, 7 October 2026: Climate tech non-profit TransitionZero is a technical delivery partner in OpenGrid, a new open source initiative launched today by the Linux Foundation and Breakthrough Energy to modernise power grid planning worldwide.

TransitionZero built the translator with support from Breakthrough Energy. It lets users convert power system models from one framework or commercial tool to another. It currently supports PLEXOS, PyPSA, Sienna, and OSeMOSYS, with more to follow.

The translator is part of TransitionZero’s open core, a growing set of free open-source tools for the core work of energy modelling. Scenario Builder, TransitionZero’s no-code planning platform, is built on top of that core. TransitionZero plans to add the translator to Scenario Builder so users can import their existing model files directly.

Why moving models between tools matters

Grid planning has become a bottleneck for the energy transition. According to the International Energy Agency, more than 2,500 gigawatts of renewable, storage, and large-load projects are stalled in grid connection queues worldwide, and annual grid investment needs to rise from $400bn to around $600bn by 2030.

Many utilities and system operators need to run planning and operation exercises across a variety of tools. The reality today is most of those tools don’t work with each other and the work to translate from one tool to another costs time and money.

The translator tackles this directly. Planners can take a model they already have and open it in another framework or tool. They can also share it with regulators, researchers, and other stakeholders, who can check the assumptions behind it.

Until now, most model converters have handled a single pair of frameworks. TransitionZero designed the translator differently: each tool needs only one converter. Once that converter exists, the framework can be translated to and from every other supported framework without extra work. Adding a fifth framework needs one new converter, not four.

An open core for energy modelling

The translator joins TransitionZero's existing open source tools, including TZ-OSeMOSYS, a Python package for the OSeMOSYS framework, and open PyPSA models such as the ASEAN Power Grid and 24/7 carbon-free electricity models.

In December, TransitionZero will release Composer, an open source workflow engine for power system models. Today, every team using PyPSA or OSeMOSYS builds its own scaffolding to organise inputs, run scenarios, check results, and document assumptions. That makes studies slow to set up and hard to reproduce. Composer provides a single, consistent way to:

• set up projects
• define and run scenarios
• manage assumptions
• produce comparable results

It also keeps a clear record of which data and assumptions led to which conclusions, so a regulator or reviewer can reproduce a published study or rerun it under different assumptions. Composer installs on a laptop with a single command and will ship first as a Python library.

The principle behind the open core is that the tools for building, running, and checking a model should be free and open to scrutiny. Scenario Builder adds what larger teams need on top of that: a no-code interface, managed compute, collaboration, and support. To become a Composer beta user before the release, email info@transitionzero.org.

Built in the open, for the planning community

"Energy plans steer billions in infrastructure investment, so the models behind them should be open to scrutiny. That's why we're putting the core of our modelling work in the open. The translator lets planners take a model built in any commercial or open source tool and convert it into another, so they can move between capacity expansion, dispatch, and power flow without building a new workflow each time. Composer, coming in December, does the same for running and reproducing studies. Scenario Builder then gives teams a no-code interface, enterprise controls, and security on top of that open foundation," said Matt Gray, CEO and Co-Founder of TransitionZero.

"Converting models between formats has been done before, but usually only between one pair of tools. We designed the translator so that each new framework works with all the others as soon as it's added. That's what makes it shared infrastructure rather than a one-off script. We're applying the same test across our open core: build tools the whole modelling community can use and extend," said Thomas Kouroughli, Head of Product at TransitionZero.

“Energy planners should be able to take a model out of the tool it was built in and run it in open source software, where anyone can inspect, question and improve it. A reliable translator into PyPSA and other open-source frameworks removes one of the biggest barriers to that. It is great to see TransitionZero building it in the open as part of OpenGrid,” said Tom Brown, Professor of Digital Transformation in Energy Systems, TU Berlin and Managing Director, PyPSA Labs.

About OpenGrid

OpenGrid is hosted by the Linux Foundation and provides a shared data and interoperability layer that lets existing commercial and open source planning tools work together. It launches with support from Breakthrough Energy GRIDS, Global Grid Catalyst, Connected Grid Initiative, and Google.org, with technical delivery partners Open Energy Transition, TransitionZero, and QXT Energy. Organisations interested in contributing can find out more here.

About TransitionZero

TransitionZero is a climate tech non-profit founded in 2021. TransitionZero develops enterprise-grade software to reduce the time to build clean energy at scale. We pioneer open source and open access tools that give policymakers, planners, investors, and developers the decision infrastructure for electricity system modelling.

Scenario Builder, our no-code platform, allows users to rapidly build, analyse, and share energy system and electricity grid models without external consultants. Supported by model migration and calibration, end-to-end data processing, in-person training, simulation-ready data, and analyst insights, Scenario Builder strengthens in-house capacity and supports resilient, affordable, and locally led energy transitions.

Since launching publicly in October 2025, Scenario Builder has expanded to cover 163 countries. AMP, our agentic AI within Scenario Builder, helps users to calibrate models, build scenarios, and analyse results. It supports nearly 1,000 users from think tanks, government agencies, electricity utilities, grid operators, renewables developers, and financial institutions.

TransitionZero is entirely grant-funded by leading climate philanthropies, including Google.org, Sequoia Climate Foundation, Bloomberg Philanthropies, and the European Climate Foundation, among others. For more information, visit our website or contact us.