Q&A Tree

CATO2 Q&A Tree

Publieke samenvatting / Public summary


This project involved organising and reformulating the output arising from CATO-2’s storage-related research into a clear and easily accessible overview of questions and answers related to the storage of CO2 in the P18-4 gas field. This information could be used to answer questions from stakeholders involved in and outside the Rotterdam ROAD CCS project.

The objective of making complex information easy to find and share was achieved through the development of an online wiki. This collated the questions and answers addressed and formulated in the CATO-2 programme, and followed a hierarchical structure running from broad, general questions down to multiple levels of detail: a question and answer decision tree.


CATO is the Dutch national R&D programme for carbon capture, transport and storage and involves a consortium of nearly 40 partners and comprises CATO-1, CATO-2 and now CATO-3. The last is funded by industrial partners and various government sources, including TKI, CLIMIT and EU ERA-NET. The CATO-2 programme aimed to facilitate and enable the integrated development of CCS demonstration sites in the Netherlands.

Project objective

A significant part of the CATO-2 programme was dedicated to researching gaps in knowledge involving the safe and secure transport, injection and geological storage of CO2. However, although the programme generated numerous answers, conclusions and reports, plus further questions, this output was not available in a form that could be easily used by subsurface storage operators to answer questions from stakeholders. Following this project, it is.

Project results

This Q&A Decision Tree was constructed in a combined top-down and bottom-up approach. It took the identification of relevant “question families” as the starting point. The Q&A Decision Tree became a powerful knowledge sharing tool that met the required goals of the project. The key strengths of the Q&A Tree were and are:

  • Key scientific outcomes and conclusions are available in one place

  • Enables structuring and linking multiple deliverables to key topics

  • Can be used to communicate to non-experts the justification of detailed research to answer societal concerns

  • Accessible and facilitates user interaction

  • Can help pinpoint where research gaps exist

  • Can be applied to all types of projects/programmes

Based on our experience, all research programmes should strongly consider developing a Q&A Tree or similar knowledge sharing tool as an integral part of a project’s communication strategy from the outset. The availability of the tool must be communicated, and it must be adequately funded as it requires active management to ensure quality control.