Quantitative assessment of safe and sustainable strategies in the pursuit of decarbonisation

Decarbonisation is a pressing challenge driven by climate change, necessitating strategies that balance environmental, societal, economic, and technological considerations. This Ph.D. research developed quantitative assessment tools to evaluate the safety-related societal impacts of decarbonisation strategies and incorporate them into a comprehensive sustainability framework. Inherent safety key performance indicators (IS-KPIs) were introduced to enable societal impact quantification and systematically integrated with specific technological, economic and environmental sustainability metrics. The robustness and applicability of the developed methodology were tested for two different case studies representative of transport and industrial applications, i.e., maritime transport and hard-to-abate sectors. In maritime transport, alternative fuels, including hydrogen, ammonia, and e-fuels, were evaluated, with e-methanol emerging as a viable option due to its moderate hazards and compatibility with existing infrastructure. While hydrogen and ammonia could reduce environmental impacts by at least 88% compared to e-fuels, their inherent hazards were up to 93 times higher. Hence, the development of robust and safe infrastructure and protocols is paramount for their widespread implementation. Onboard carbon capture and storage (OCCS) demonstrated potential for reducing emissions by up to 68%, promoting its adoption as a transitional solution until cleaner fuels become viable. For industrial decarbonisation, carbon capture and storage (CCS) was examined for mitigating hard-to-abate emissions. Sustainability decreased significantly at smaller emission scales, with costs rising by up to 300% when the targeted scale was 14 times lower. To mitigate costs, a centralised CCS strategy for smaller, spatially dispersed emitters is recommended, reducing costs by at least 25% compared to on-site CCS. The concept was extended to hydrogen-based strategies using liquid organic hydrogen carriers, which outperformed CCS for combustion-driven emissions, though CCS remained the most effective solution for process-related emissions. This research provides practical insights for developing and implementing safer and more sustainable decarbonisation technologies that align with global climate targets.