Limiting climate heating while meeting basic needs for all necessitates large-scale deployment of renewable energy. Understanding the dynamics of mobilizing materials for the transition requires considering: 1) availability of resources in the environment and technosphere; 2) accessibility depending on resource quality and available technologies; 3) processability depending on energy availability, processing capacity, and impacts on planetary boundaries; and 4) operability depending on social acceptance and geopolitical agreements. Materials can be mobilized through four routes: 1) increasing primary production; 2) diverting existing primary production; 3) repurposing in-use stocks; and 4) re-mining wastes and emissions. The interplay of these enabling factors, material efficiency in design, and substitution with materials that are easier to mobilize determines the maximum possible rate of material mobilization and consequently the energy transition itself. This paper presents and discusses a framework to explore joint energy-material transformations, enabling to consider material aspects in transition modelling and guide technological developments.