Carbon Dioxide Emissions, Capture, Storage and Utilization: Review of Materials, Processes and Technologies

Carbon capture and storage (CCS) is an essential component of mitigating climate change, which arguably presents an existential challenge to our planet. Although CO2 emissions have been on the global agenda for several decades, progress has been extremely slow, insufficient and sporadic. Anthropogenic CO2 emissions are the direct result of our addiction to fossil fuels, and in 2018 accounted for 68% (or, 37.5 GtCO2) out of the total greenhouse gas (GHG) emissions of 55.3 GtCO2e globally. Capturing CO2 at such massive quantities would require resources and technologies that can operate cost-effectively at the multi-gigaton scale, which we currently lack. Moreover, CO2 capture is an expensive and highly energy intensive process complicated further by logistics and the diversity of the emission sources that vary by volume, composition, location, type, and industry or sector. At the same time, however, such diversity also highlights that one size does not fit all, and hence, dictates the need for a multi-prong strategy that emphasizes the necessity to develop wide range of CCS technologies, materials and processes. This article presents a global overview and impartial assessment of the current state of CCS challenges in an extensive manner covered under the main headings of pre- and post-combustion CO2 capture, direct air capture, CO2 transport and storage and utilization, and carbon pricing. Materials aspects of post-combustion CO2 capture technologies are reviewed in detail. The article provides critical discussions of fundamental phenomena and recent advances in the field, as well as tutorial-type background information, where appropriate. The article reviews the status of global CO2 emissions as well as carbon sources and sinks, and examines a broad range of major technologies, methodologies, processes, and materials for CO2 capture, discusses technology options for carbon capture from fossil fuel-based power generation, presents the challenges to storage, utilization and the global pricing of CO2, and finishes with an assessment of knowledge gaps, mitigation options and opportunities for advances. The article emphasizes the fact that there are no easy fixes or cheap technological solutions to the interconnected problems of energy, CO2 emissions and climate change. The threats to Earth's ecosystems are too real and imminent to be judged and driven only by economics. In this existential context, the choice between ‘pay now’ or ‘pay later’ is clear and paying later will be much more expensive. The world must act now.