A viable CCS project depends on effective implementation and confidence in long-term confinement; not only supported by technical specialists in implementing and regulatory organisations, but also by the wider scientific community, political decision makers and the general public. However, sharing knowledge between, and building confidence in, individuals with different experience and value systems is not an easy task. Thus, it is vital to have a framework in which we can make use of and share various sources of ‘knowledge’, from a variety of different scientific disciplines, and integrate them into a logical structure that allows optimisation of project implementation and strengthens the supporting safety case. An advanced KMS (Knowledge Management System) would provide such a framework, with special emphasis on making knowledge available in a form that contributes to confidence building in CCS. An advanced KMS is not a passive tool to archive and disseminate information–it can help synthesising and integrating material from diverse sources, identifying trends and inconsistencies and giving feedback to data producers. This provides an overview of project progress and provides advance warnings of potential problems in the future. Here we focus on knowledge sharing between projects with emphasis on the “storage” side of CCS, which has particular challenges in terms of both socio-political sensitivity and its complex, multi-disciplinary nature.