Collaborative governance of carbon mitigation, energy transition, and material management: A factorial non-deterministic carbon-energy-metal nexus optimization model

Clean energy transition increases management challenges of energy transition metals (ETMs). To support collaborative governance of carbon mitigation, energy transition, and material management, this study develops a factorial non-deterministic carbon-energy-metal nexus optimization model that explicitly quantifies nexus interactions, trade-offs and synergies, and multidimensional uncertainties. Through integrating non-deterministic optimization, dynamic material flow analysis, and factorial design, the model analyzes spatiotemporal metal dynamics under various transition scenarios and examines interactive effects of mixed-level material management strategies on carbon mitigation and resource savings. It is applied to Canada’s electricity and passenger transport sectors over 2031–2050. By 2050, Canada’s electricity capacity would reach 1.4–1.5 times its 2023 level, driven by expansion of wind, solar and small modular reactors. Vehicle stocks would increase by 1.3–1.7 times, alongside near-complete electrification. In-use 35 ETM stocks would rise tenfold, reaching 6.9–9.1 Mt under the net-zero scenario, with metal inflows consistently exceeding outflows (with a ratio > 2). Significant provincial disparities in metal stock changes indicate higher material pressures in Saskatchewan, Alberta, and New Brunswick. Material strategy analysis reveals that extending electric vehicle lifetime could avoid 47.8–55.8 Mt of rebound emissions, whereas reducing material intensity could lower per capita demand for cobalt, dysprosium, nickel, and indium by 27.9–56.3%. Combining lower material intensity, higher recycling, and longer lifetimes could achieve additional emission reductions of 68.3–83.6 Mt, while lowering per capita metal demand by nearly 50%. These findings enhance understanding of carbon-energy-metal nexus complexities and support decision-making toward a net-zero future.