Limiting climate change to less than 1.5 o C would require vast quantities of CO2 storage in subsurface geological formations. Global injection rates projected by integrated assessment models synthesised in IPCC reports are on the order of ten gigatonnes per year by 2050. Industrial experience with megatonne per year storage projects allows us to evaluate the feasibility and potential limitations of a transition to the gigatonne scale. The successes with CO2 have also led to interest in new energy technologies using subsurface fluids, including hydrogen storage underground. We review the role of subsurface CO2 and H2 storage in a sustainable energy transition. We have found that current deployment demonstrates the viability of CO2 storage in a variety of geological, social, economic, and technological contexts, and is making contributions to climate change mitigation today commensurate with the impact of solar photovoltaics in the USA market. The implications of this are that CO2 storage is well positioned to play an important role in the energy transition, and H2 storage may benefit from this experience. However, these are not certain outcomes, with many hurdles -the development of multi-site regional scale storage, viable business models for accelerated deployment, demonstrating environmental sustainability and achieving societal acceptability -yet to be addressed.

This article investigates the relationship between additive induced creeping and anticaking activity in sodium chloride. Through a series of creeping experiments and powder flow analysis, we establish a clear correlation between the amount of creeping and the anticaking effect of an additive. Habit modification is found not to be a sufficient condition for an anticaking agent. The correlation is explained by the fact that both creeping and anticaking require blocking of crystal growth.Creeping pattern of saturated brine with 1% (w/w) nitrilotriacetamide (NTAA). AbstractThis article investigates the relationship between additive induced creeping and anticaking activity in sodium chloride. Through a series of creeping experiments and powder flow analysis, we establish a clear correlation between the amount of creeping and the anticaking effect of an additive. Habit modification is found not to be a sufficient condition for an anticaking agent. The correlation is explained by the fact that both creeping and anticaking require blocking of crystal growth.

This paper assesses the role of carbon dioxide capture and storage (CCS) in addressing challenges in the energy transition in regions reliant on carbon-intensive industries for employment and as an economic base. The assessment is based on semi-structured interviews with relevant stakeholders and experts in the Aberdeen area in Scotland, the Rotterdam harbour (or Rijnmond) area in the Netherlands, and in Norway. The interviews explored challenges around the role of CCS in regional 'just transitions', or how to make the transformation of regions relying on carbon-intensive industries to a low-carbon society fair. While significant differences in responses between the Aberdeen area, the Rijnmond area and Norway were found, a common understanding showed that for CCS to contribute to a just transition it has to (a) make a contribution to climate change imperatives; (b) help to mitigate the economic and employment effects arising from declining or maturing industries; and (c) be undertaken in a manner that helps to redress (or at least does not increase) uneven vulnerabilities and inequalities in society. Five key themes that characterise the opportunities and challenges for CCS from a just transition perspective were drawn from the interviews: Skills for a just transition, transition as an opportunity, responsibility, scale of action and viability. We recommend that these are added to earlier work on barriers and enablers of CCS in areas relying on fossil industry.

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