Overcoming the challenges of assessing the global raw material demand of future energy systems

The transition of the energy system demands a wide range of raw materials, resulting in projections of rapid demand growth. Many of these commodities are already classified as critical due to a combination of their economic importance and various risks of supply disruption. In this review on the latest developments in modeling the energy-material nexus, we reveal that the research field is currently dominated by ex-post analyses of preexisting energy scenarios, although the number of model-based analyses has increased in recent years. We identify several challenges, such as the introduction of unintended biases or the unrealistic and insufficient representation of technology characteristics and future developments. Model-based approaches promise more realistic results, but their applicability and scope are still limited by the resulting complexity of the underlying models. We show that many of the identified challenges can be addressed with methods currently available and present a collection of best practice recommendations to improve the quality of future analyses. Finally, we provide an overview of research areas that have yet to be thoroughly explored, such as the supply side of raw materials, by-products, or the economic and environmental implications of the use of raw materials.