A Multi-Criteria Framework for Circular Carbon Pathways: Integrating Life-Cycle Sustainability, Techno-Economics, and System Optimization

Unofficial AI-generated summary based on the public title and abstract. Not an official translation.

🔬研究者:Provides a systematic framework integrating LCA, TEA, and optimization for evaluating transport decarbonization options; useful for energy systems and sustainability assessment researchers.

🏢実務担当者:Corporate sustainability teams can use the framework to assess investments in hydrogen, electric, and e-fuel pathways for fleet and fuel procurement decisions.

🏛政策担当者:Offers evidence-based analysis on how local conditions shape optimal decarbonization pathways; supports design of transport fuel mandates and infrastructure policies.

The Paris Agreement sets the objective of limiting the increase in global average temperature to well below 2°C above pre-industrial levels, while pursuing efforts to restrict the increase to 1.5°C. Achieving these targets requires deep decarbonization across all major emitting sectors, among which transport remains particularly challenging because of its continued reliance on fossil fuels and its substantial contribution to global greenhouse gas emissions. Carbon neutrality in the transport sector therefore depends not only on advances in vehicle and propulsion technologies, but also on the deployment of low-carbon energy carriers, including hydrogen, electricity, and sustainably produced liquid and gaseous carbon-based fuels. A rigorous understanding of the environmental and economic implications of these emerging pathways is thus essential for informing effective policy and investment decisions. Against this background, this work develops a comprehensive framework integrating life-cycle assessment (LCA), techno-economic analysis (TEA), and optimization to evaluate circular low-carbon pathways in transport and energy systems, with particular emphasis on Saudi Arabia and broader global applications. The framework incorporates multiple life-cycle assessment per spectives, including conventional LCA, prospective LCA, and planetary boundary-based LCA, together with TEA and mathematical optimization, in order to enable a systematic evaluation of technological alternatives from environmental, economic, and systems perspectives. The work is structured around four interconnected research themes. First, it investigates decarbonization options for urban bus transport in Saudi Arabia by comparing diesel, battery electric, and hydrogen fuel cell buses under well-to-wheel and tank-to-wheel system boundaries. Second, it conducts a global environmental assessment of passenger vehicle energy carriers and powertrain technologies, explicitly accounting for regional heterogeneity in electricity generation and fuel production pathways. Third, it evaluates the life-cycle environmental and techno-economic performance of power-to-fuel systems in the Saudi Arabian context, including e-methanol, methanol-to gasoline, methanol-to-jet, and Fischer–Tropsch diesel and jet fuel pathways, across alternative electrolyzer technologies (PEM, AEL, and SOEC) and carbon dioxide supply options, including point-source capture and direct air capture (DAC). Fourth, it develops a mixed-integer linear programming (MILP) framework for optimizing global electro-sustainable aviation fuel (e-SAF) pathways while explicitly accounting for renewable energy variability and policy constraints such as ReFuelEU Aviation and CORSIA. The findings show that no single decarbonization pathway is universally optimal; rather, the preferred strategy depends strongly on local and regional conditions, including the energy mix, infrastructure availability, resource endowments, and policy context. The results further highlight the central roles of renewable energy integration, carbon dioxide sourcing, circular carbon utilization, and system-level optimization in enabling substantial emissions reductions across transport and energy systems. Taken together, this work provides policy-relevant evidence to support Saudi Arabia’s Vision 2030 energy transition and offers methodological advances of broader relevance to global decarbonization efforts.

• openalex https://doi.org/10.25781/kaust-041g3first seen 2026-07-27 04:53:55