Enhancing the realism of decarbonisation scenarios with practicable regional constraints on CO2 storage capacity

Abstract

• Integrated assessment model scenarios substantially overestimate CO 2 storage potential. • A new storage potential estimate, the investable potential, is introduced. • Reduced CO 2 storage requires faster mitigation and greater use of renewable energy. • Scenarios prioritise very different CCS applications depending on storage availability. • The impact of cross-border trade in CO 2 and low discount rates are also explored. Most low-carbon scenarios produced by integrated assessment models deploy substantial amounts of carbon capture and storage (CCS). These models generally assume that CO 2 storage is a low-cost and globally ubiquitous resource. Here we challenge this assumption, introducing a CO 2 storage potential which accounts for the financial, contractual, and institutional barriers to CO 2 storage, which we term the investable potential. We provide a first estimate of this investable potential and utilise a global energy system model to explore the implications for global and regional mitigation pathways. Our results suggest that low-carbon scenarios which assume abundant CO 2 storage may substantially overestimate the role of CCS in deep decarbonisation, particularly in key regions such as China and India. Limited CO 2 storage leads to mitigation pathways with faster emission reductions and greater reliance on renewable energy for decarbonisation. We demonstrate that the optimal use of CCS depends heavily on the availability of CO 2 storage, with different use-cases prioritised at different scales of storage availability. Finally, we present exploratory analysis on the potential for cross-border trade in captured CO 2 to match sources and sinks. The results of this analysis can help calibrate expectations and inform policy decisions around the role of CCS in addressing climate change.