Exergy assessment of the Spanish recovery capacity of secondary resources essential for the ecological transition

The increasing global demand for raw materials, driven by population growth, globalization, and shifting consumption trends, poses significant challenges to resource sustainability. The ecological transition, which seeks to replace fossil fuel dependency with renewable energy sources, will further intensify the demand for critical minerals essential for wind turbines, photovoltaic panels, and electric vehicles. This shift highlights a growing reliance on mineral resources, many of which are scarce and require substantial energy input for extraction and processing. Exergy analysis provides a comprehensive framework for assessing the physical feasibility of raw material recovery. By quantifying the exergy replacement costs of minerals, it is possible to evaluate their physical quality, avoiding unfair comparisons. This approach allows for a more accurate representation of resource scarcity and highlights the thermodynamic limits of sustainability strategies such as circular economy initiatives and urban mining. Urban and secondary mining have emerged as potential alternatives to conventional mining, offering opportunities to recovervaluable materials from waste streams, abandoned mining sites, and discarded technological products. However, the viability ofthese processes depends on multiple factors, including the concentration of recoverable materials, technological feasibility, andeconomic considerations. Understanding these constraints is crucial for designing efficient recovery strategies and reducingdependency on primary raw materials. This study focuses on assessing Spain’s capacity for recovering secondary resources through a rigorous thermodynamic approach. By developing an inventory of materials available in mining and technological wastes, this research aims to identify feasible recovery pathways. The findings will contribute to a roadmap for optimizing raw material use, enhancing resource efficiency, and mitigating supply risks in the context of the ecological transition. Ultimately, the results will provide valuable insights into the exergy-based limitations of raw material recovery and support informed decision-making for a more sustainable resource management strategy