Energy and carbon footprint of metals through physical allocation. Implications for energy transition

The increasing metal demand driven by energy and digital transition has led to more complex mining operations. To allocate environmental impacts in cases of mining co-production, this study proposes a physical method based on the relative geological scarcity of elements, which provides the basis for an exergy cost allocation. It focuses on calculating the energy and carbon footprint of 51 metals, including 28 co-products, based on available databases. The analysis considers the fuel type, main production stages and the energy footprint of up to 25 chemicals. This study provides new insights into 39 infrequently studied metals. Results show that by using renewable electricity in production, 41 metals can reduce their carbon footprint by up to 50 %. However, key metals such as Fe or Li require additional decarbonization efforts beyond electricity. Only by decarbonizing metal production is possible a renewable infrastructure that can achieve the energy transition goals.