The CO2QUEST proposal addresses the fundamentally important issues regarding the impact of the typical impurities in the gas or dense phase CO2 stream captured from fossil fuel power plants on its safe and economic transportation and storage.The proposed work programme will focus on the development of state-of-the art mathematical models backed by laboratory and industrial-scale experimentation utilising unique EC funded test facilities to perform a comprehensive techno-economic, risk-based assessment of the impact of the CO2 stream impurities on phase behaviour and chemical reactions, and on pipeline and storage site integrities.The above involves the determination of the important CO2 mixtures that have the most profound impact on the pipeline pressure drop, compressor power requirements, pipeline propensity to ductile and brittle facture propagation, corrosion of the pipeline and wellbore materials, geochemical interactions within the wellbore and storage site, and the ensuing health and environmental hazards. Based on a cost/benefit analysis and whole system approach, the results will in turn be used to provide recommendations for tolerance levels, mixing protocols and control measures for pipeline networks and storage infrastructure.CO2QUEST addresses all the main themes of this Call in several ways. It involves the active participation of key players from the Carbon Capture Sequestration Forum, in particular China (partner), Canada and USA (Strategic Committee Members), and the world’s leading steel producer representing a CO2 intensive industry. CO2QUEST involves the participation of leading academics with directly relevant fundamental and pre-normative research track records. A main focus of attention will be maximising the project’s impact by ensuring that its results are effectively exploited and actively disseminated, in particular, supporting the development of relevant design and operation standards for CCS infrastructure.