Navigate is a sectoral integrated assessment model for simulating the maritime industry's transition toward zero-carbon shipping. It models fleet investment decisions, fuel production, bunkering operations, and regulatory impacts over multi-decade timelines.
Navigate is an open-source analytical model intended for research and scenario analysis of maritime decarbonisation pathways. The model, its assumptions and any outputs are provided for illustrative and analytical purposes only.
Model outputs depend on the assumptions selected by the user and should not be interpreted as forecasts, benchmarks, recommendations or commercially optimal outcomes, nor as legal, financial or investment advice.
Users are responsible for selecting and adapting assumptions appropriate to their own circumstances and for exercising their own independent judgement when interpreting or relying on any model outputs.
Navigate is built on Python version 3.12. You can download Navigate by cloning it to your local machine or by downloading one of the releases. We recommend using an environment manager such as conda or venv to avoid conflicts with other packages and versions.
# Using venv (bundled with Python)
python3.12 -m venv .venv
source .venv/bin/activate
# Using conda (https://www.anaconda.com/docs/getting-started/miniconda/install)
conda create -n nav python=3.12 pip
conda activate navInstall navigate using pip from within the Navigate folder after cloning the repository:
pip install .Navigate ships with the open-source HiGHS solver and uses it by default — no further setup is needed. If you have a Gurobi license, you can install the faster Gurobi backend as an optional extra:
pip install .[gurobi]The default --solver auto then detects the license and uses Gurobi automatically. Note that installing gurobipy from pip only includes a size-limited trial license that cannot solve full Navigate scenarios — without a full Gurobi license, skip this extra (or run with --solver highs).
Navigate is run from the command line using the following command:
navigate my_nav_file.navFor example, to run the basecase scenario with the included assumptions and export them to Excel:
navigate simulations/scenarios/basecase_mid_regulation/basecase_mid_regulation.nav -d ./assumptions -eExpect a full scenario run to take roughly 25 minutes on the bundled open-source HiGHS solver. The four reference scenarios are described in simulations/scenarios/README.md.
The following options are available when running Navigate. See them in the command line by typing navigate --help.
| Flag | Description |
|---|---|
-d DIR, --data-dir DIR |
Folder location for assumptions that may be imported. Can also be set with the environment variable ASSUMPTIONS_DATA_DIR. The Mærsk Mc-Kinney Møller Center for Zero Carbon Shipping supplies assumptions in the assumptions folder of this repository. |
-s, --suppress-plots |
Suppress the generation of plots at the end of the simulation. Excel reports will still be generated. |
-e, --export-assumptions |
Export assumptions in an Excel format. |
-l LEVEL, --log-level LEVEL |
Set the log level for the .log file. With DEBUG, a failed run also prints the full traceback to the console. |
-r PATH, --replot PATH |
Regenerate plots from previously exported plot data. Provide path to directory containing plot_data.pkl or to the file directly. Skips simulation. Optionally pass a .inc file with Plot node(s) as the trailing argument to use those instead of the plot nodes stored in the plot data. |
--solver {auto,gurobi,highs} |
Solver backend. auto tries Gurobi then falls back to HiGHS. Default: auto. |
-p, --profile |
Profile the computational performance of the simulation. Note that this suppresses all output that is not directly related to the simulation. |
Step-by-step tutorials and a full reference manual are available in the documentation. The tutorial project files live in the tutorials/ folder.
Some simple example simulations can be found under simulations/examples
Copyright 2026 Fonden Mærsk Mc-Kinney Møller Center for Zero Carbon Shipping.
Navigate is licensed under two licenses, depending on the type of content:
- The software — the
navigatepackage, tests, and all build, tooling, and editor-support files — is licensed under the Apache License 2.0 (see also the root LICENSE file). - The model content — assumptions, simulation and input files written in the Navigate DSL, tutorials, documentation, and figures — is licensed under Creative Commons Attribution 4.0 International (CC-BY-4.0).
Every file declares its license through an SPDX-License-Identifier header or through the metadata in REUSE.toml, following the REUSE specification. The full license texts are in the LICENSES directory.