A new open source framework for advanced life cycle assessment calculations.

It is designed to be easy to use, while still being powerful.

Like living on the edge? Try the development documentation!

Introduction | Motivation | Principles | Technology | Contributing | Credits


Brightway2 is a completely new program for calculating life cycle assessments (LCA). Its core principles are simplicity, innovation, and power. It can be installed on Windows, OS X, and Linux, and has a web interface.


The pace of innovation in software can be overwhelming, but one would struggle to call any existing LCA software truly innovative. User interfaces are painfully dated, calculations are slow and poorly documented, and new ways of consuming information such as the web are ignored. Brightway2 is not trying to replace software such as OpenLCA or SimaPro. Instead, it is designed for individual analysts to do cutting edge calculations on their computers, their servers, or in the cloud, and to push the state of the art in LCA result visualization.

Only Brightway2 can:



Software used:

BW2 packages:

Brightway2 is designed to be simple, so let's start by talking about what it doesn't have. First, it doesn't have an SQL, or even NoSQL, database. Because it is not designed for teams, the costs of installing, tuning, and maintaining a database are not worth it. Instead, data is saved as documents in a data directory, which means that they can be easily backed up, or even put on Dropbox. No database also means that installation is quicker and easier.

Brightway2 is written primarily in Python, and uses the fantastic NumPy and SciPy libraries for matrix algebra. Although Python is not a fast language, Brightway2 can perform LCA calculations quickly: a single calculation takes around one tenth of a second, and Monte Carlo uncertainty analysis on a large scale is quick. On a 2011 laptop, around 100 iterations a second are possible.

Result graphics are displayed using D3.js. D3 is just an amazing library - powerful, yet simple to understand and easy to tinker with. For example, the built-in graphics for Brightway2 can be edited online in, e.g. supply chain circles, and the complete list is here. New visualizations offer new possibilities for both experienced LCA practitioners and lay people to understand the results of LCA studies.


Brightway2 is an open source project, released under the BSD license, and all code is hosted online. You don't have to be a programmer to help make small improvements, however! I am not a programmer, but taught myself Python during my studies. Here is how you (yes, you) can help:

See the guide to contributing for more information, including easy projects for non-programmers, and a detailed list of possible improvements.


Brightway2 was created by Chris Mutel during his postdoctoral work at the group for Ecological Systems Design, led by Professor Stefanie Hellweg, and was funded by the Swiss National Science Foundation and ETH Zürich.

This webpage by Chris Mutel is licensed Creative Commons License.