The main objective of ACTiON is to establish how an efficient infrastructure, connecting CO2 sources with CO2 geological storage and non-geological utilization options, can be developed as part of regional decarbonisation efforts. ACTiON aims to research and develop a multitemporal integrated assessment model that will support stakeholders in the planning and design of large-scale, flexible CO2 transport, utilisation and storage networks. ACTiON will address geological and engineering constraints, the impact of economic conditions and regulatory environment, as well as the unavoidable uncertainties in defining them. A thorough understanding of the impact of flow phenomena on network design and operation is essential to de-risk the integrated operation by building in flexibility and resilience in response to operational changes in different parts of the chain. Will demonstrate the interplay between such issues by combining them into integrated component models for optimisation of transport, storage and utilisation networks. Complex subsurface and engineering features and processes, such as geological flow barriers, geo-mechanical constraints and well performance, will be implemented as modular computationally independent proxy models to provide the building blocks for integrated models. ACTION will consider networks that link multiple suppliers of CO2 to multiple injection wells and storage locations including depleted fields, saline aquifers and EOR. ACTION will aim to provide the building blocks and workflows for network developers, as basis for efficient design and safe operations. The multitemporal modelling capabilities will be applied to a number of case studies that cover approaches to CCUS network development in different EU Member States, the US and Canada. Pipeline and ship transport will be included, as will be networks of different complexity aiming to support the development of fit-for-purpose, future-proof CO2 transport, utilization and storage networks.