Critical metals: Their applications with emphasis on the clean energy transition

The global demand for metallic mineral resources has been rising constantly not only due to the world's continued population growth, but also accelerated by the recently proclaimed 'green energy transition' aiming to replace fossil fuels by wind, solar, hydrogen, and geothermal energy. The current situation causes a dilemma as the supply of metallic mineral resources is limited and, at least when this article was written, most critical metals neither can be substituted nor recycled economically and at industrial scale. As a consequence, metallic mineral resources must be considered as non‐renewable commodities. This study documents the main industrial applications and supply risks of the critical metals with special emphasis on their respective roles for the green (also referred to by the media as clean or renewable) energy transition. In summary, the natural distribution of critical metals in the Earth's upper crust is very heterogeneous and, at current consumption rates, will likely lead to supply risks in the near future. More specifically, >40 vol% of the global reserves of critical metals, such as chromium, palladium, and platinum (South Africa), cobalt (Democratic Republic of Congo), cadmium, indium, rare earth elements, and tungsten (China), are concentrated in only a single country with obvious geopolitical and strategic implications. Importantly, most of these strategic metals, apart from chromium, are considered crucial for the success of the green energy transition.