Carbon capture and storage (CCS) is broadly recognised as having the potential to play a key role in meeting climate change targets, delivering low carbon heat and power, decarbonising industry and, more recently, its ability to facilitate the net removal of CO₂ from the atmosphere. However, despite this broad consensus and its technical maturity, CCS has not yet been deployed on a scale commensurate with the ambitions articulated a decade ago. Thus, in this paper we review the current state-of-the-art of CO₂ capture, transport, utilisation and storage from a multi-scale perspective, moving from the global to molecular scales. In light of the COP21 commitments to limit warming to less than 2 °C, we extend the remit of this study to include the key negative emissions technologies (NETs) of bioenergy with CCS (BECCS), and direct air capture (DAC). Cognisant of the non-technical barriers to deploying CCS, we reflect on recent experience from the UK's CCS commercialisation programme and consider the commercial and political barriers to the large-scale deployment of CCS. In all areas, we focus on identifying and clearly articulating the key research challenges that could usefully be addressed in the coming decade.

Metal–organic frameworks (MOFs) have taken the materials science world by storm, with potentials of near infinite possibilities and the panacea for adsorption-based carbon capture. Yet, no pilot-scale (or larger-scale) study exists on MOFs for carbon capture. Beyond material scalability issues, this clear gap between the scientific and engineering literature relates to the absence of suitable and accessible assessment of MOFs in an adsorption process. Here, we have developed a simple adsorbent screening tool with process economics to evaluate adsorbents for post-combustion capture, while also considering factors relevant to industry. Specifically, we have assessed the 25 adsorbents (22 MOFs, 2 zeolites, 1 activated carbon) against performance constraints – i.e. CO₂ purity and recovery – and cost. We have considered four different CO₂ capture scenarios to represent a range of CO₂ inlet concentrations. The cost is compared to that of amine-based solvents for which a corresponding model was developed. Using the model developed, we have conceptually assessed the materials properties and process parameters influencing the purity, recovery and cost in order to design the ‘best’ adsorbent. We have also set-up a tool for readers to screen their own adsorbent. In this contribution, we show that minimal N₂ adsorption and moderate enthalpies of adsorption are key in obtaining good process performance and reducing cost. This stands in contrast to the popular approaches of maximizing CO₂ capacity or surface area. Of the 22 MOFs evaluated, UTSA-16 shows the best performance and lowest cost for post-combustion capture, having performance in-line with the benchmark, i.e. zeolite 13X. Mg-MOF-74 performs poorly. The cost of using the adsorbents remains overall higher than that of an amine-based absorption process. Ultimately, this study provides specific directions for material scientists to design adsorbents and assess their performance at the process scale. This works intends to bridge the gap between scientific and engineering studies to accelerate CO₂ capture adsorbents development. The approach can be extended to other molecular separations.

Carbon dioxide removal (CDR) is essential to deliver the climate objectives of the Paris Agreement. Whilst several CDR pathways have been identified, they vary significantly in terms of CO₂ removal efficiency, timing, and permanence.

In this study we evaluate the feasibility of the recovery of waste heat from the power plant boiler system of a pulverised fuel power plant with amine-based CO2 capture. This recovered heat can, as a function of fuel type and solvent selection, provide up to 100% of the heat required for solvent regeneration, thus obviating the need for withdrawing steam from the power plant steam cycle and significantly reducing the efficiency penalty imposed upon the power plant by the CO2 capture process. In studying the thermochemistry of the combustion process, it was observed that co-firing with low moisture biomass achieved higher adiabatic flame temperatures (AFT) than coal alone. The formation and emission of SOX reduced as biomass co-firing proportion increased, whereas NOX emissions were observed to be a function of AFT. The power generation efficiency of a 500 MW 50% co-firing BECCS system increased from 31%HHV with a conventional MEA solvent, to 34%HHV with a high performance capture solvent. The heat recovery approach described in this paper enabled a further efficiency increase up to 38%HHV with the high performant solvent. Such a system was found to remove 0.83 MtCO2 from the atmosphere per year at 90% capacity factor

This study evaluates the performance of a 500 MW pulverised fuel BECCS system. A performance matrix is developed to assess the opportunities for BECCS performance improvement in terms of: energy efficiency, carbon intensity, and pollutant emissions. The effect of fuel properties was analysed for variable (i) coal type (high/medium sulphur content), (ii) biomass type (wheat straw and wood chips), (iii) moisture content, and (iv) biomass co-firing proportion %. It was observed that the co-firing of biomass increased the quantity and quality of waste heat available for recovery from the exhaust gas. The opportunities to improve energy efficiency in the BECCS system include enhancing heat recovery and using high performance solvents for CO2 capture, such as biphasic materials. Implementing these approaches increased the power generation efficiency from 31%HHV (conventional MEA system) to 38%HHV (using an advanced biphasic solvent with heat recovery). Furthermore, power generation efficiency was found to influence the carbon intensity on an annual basis and annual capacity (load factor) of the BECCS system. Significant reductions to SOX emissions were achieved by increasing biomass co-firing % or using low sulphur coal