The Resource‐Energy Nexus as a Key Factor for Circular Economy

Abstract

The extraction of raw materials is associated with energy input and CO2 emissions. What is obvious for extraction from mining, however, also applies to recycling. Mostly, recycling is preferred for reasons of climate protection or because of the geological scarcity of raw materials, which is controversially discussed. While in mining, the declining ore grade is a driver for the energy demand, in case of recycling it is the dissipation of materials into products or waste. As concentration decreases, the effort required also increases disproportionately. The “closing the loop” metaphor of Circular Economy is therefore inappropriate in its stricter meaning. It is rather about optimizing the overall system and finding the optimal recycling rate. However, first, it must be clarified what the political goals for Circular Economy are.

How much sorting is required for a circular low carbon aluminum economy?

“…However, a 100% collection rate, as tested by the model, is unrealistic and probably unwanted. As formulated by Schmidt (2021): “[…] there is an optimum for the recycling rate that is well below 100 %. This is due to the dissipation of elements in materials and the increasing energy demand at low concentrations.” Further research could explore this optimal recycling rate specifically for the aluminum industry.…”

“…Due to dismantling and sorting challenges, a specific circular initiative could lead to counter‐productive gains within the system. As cited by Schmidt (2021): “The ‘closing the loop’ metaphor of Circular Economy is therefore inappropriate in its stricter meaning. It is rather about optimizing the overall system […].” Increasing recycling should not be the absolute priority but should be considered as a means to improve the system according to its specific barriers and constraints.…”

“…Due to dismantling and sorting challenges, a specific circular initiative could lead to counter-productive gains within the system. As cited by Schmidt (2021): "The 'closing the loop' metaphor of Circular Economy is therefore inappropriate in its stricter meaning. It is rather about optimizing the overall system [.…”

Mobilizing materials to enable a fast energy transition: a conceptual framework

“…Increasing circularity in society can help to maintain current in-use stocks with less primary input, allowing to divert existing primary production for building RE stocks. While reducing final consumption and reuse can make more energy available for mobilizing materials, upscaling recycling may increase energy demand through the increased efforts for collection, sorting and purification (Schäfer, 2021;Schmidt, 2021;Baum, 2018). During the transition, parts of the current fossil infrastructure-primarily composed of steel, Al, Cu, and concrete (Le Boulzec et al, 2022)-gets replaced and becomes obsolete.…”

“…The energy demand for mobilizing materials will change non-linearly with material flows. Declining ore grades tend to increase energy demand in an inversely proportional way (Koppelaar and Koppelaar, 2016;Calvo et al, 2016;Magdalena et al, 2021;Michaux, 2021b;Northey et al, 2014), while learning effects from scaling production and improved technologies may reduce it (Schmidt, 2021). Given the need to accelerate the energy transition, it remains an open question how quickly learning can be realised Grafström and Poudineh, 2021).…”