Thermodynamic Rarity and Recyclability of Raw Materials in the Energy Transition: The Need for an In-Spiral Economy

Abstract

This paper presents a thermodynamic vision of the depletion of mineral resources. It demonstrates how raw materials can be better assessed using exergy, based on thermodynamic rarity, which considers scarcity in the crust and energy requirements for extracting and refining minerals. An exergy analysis of the energy transition reveals that, to approach a decarbonized economy by 2050, mineral exergy must be greater than that of fossil fuels, nuclear energy, and even all renewables. This is because clean technologies require huge amounts of many different raw materials. The rapid exhaustion of mines necessitates an increase in recycling and reuse, that is, a “circular economy”. As seen in the automobile industry, society is far removed from closing even the first cycle, and absolute circularity does not exist. The Second Law dictates that, in each cycle, some quantity and quality of materials is unavoidably lost (there are no circles, but spirals). For a rigorous recyclability analysis, we elaborate the exergy indicators to be used in the assessment of the true circularity of recycling processes. We aim to strive toward an advanced economy focused on separating techniques and promoting circularity audits, an economy that inspires new solutions: an in-spiral economy.

Biogas Production from Organic Wastes: Integrating Concepts of Circular Economy

“…However, infinite recycling of any quantity is not possible due to the intrinsic thermodynamics limits. Absolute circularity in any transformation process is hopeless because in each cycle, there is a loss in the quality and quantity of the material, which is unavoidable, as stated by the second thermodynamic law [1]. Therefore, the idea of a circular economy is more often celebrated, instead of being critically analyzed by the scientific community, since its implementation results are limited and fragile because the circular economy is achieved mostly through global recycling networks [2].…”

Exergy-Based Assessment of Polymers Production and Recycling: An Application to the Automotive Sector

“…In order to evaluate the recycling process, exergy-based recycling indexes are developed, depending on the final product, namely the new crude polymeric material (primary product) or the oil derivatives (secondary products). Examples of developing of exergybased indicators for products life cycle are present in [66]. Figure 2 A new polymer can be obtained by mechanical recycling (as in the case of PE, PP, PVC, ABS and PET) or via chemical recycling through decomposition into the constituent macromolecules and consequent re-polymerization (as for PU, PA6.6, PET, SBR, EPDM).…”

Resumen y análisis crítico del informe especial de la Agencia Internacional de la Energía: El Rol de los minerales críticos en la transición hacia energías limpias

“…At this point, the IEA report acknowledges the problem that some of us thermodynamicists have pointed out: metal mixology implies irrecoverable losses at the End of Life (Reuter et al, 2006;Valero, and Valero, 2019). This challenge is essential because recoverability depends on how the metals are mixed, alloyed, etc.…”