Investigating extraterrestrial bodies as a source of critical minerals for renewable energy technology

Abstract The Paris Agreement set a goal of limiting the Earth’s average temperature increase in order to reduce the threat of climate change. Fundamental to achieving this goal will be a large global increase in renewable energy generation and storage capabilities, particularly photovoltaic cells, wind turbines, batteries, and fuel cells. However, an often overlooked aspect of a large scale shift to renewable technologies is the increasing demand this creates for the mineral resources used in their manufacture. Some of these minerals have high-risk supply chains that threaten their production, resulting from various economic, social, geopolitical and geological factors. These important and high risk minerals are known as critical minerals. Many of these critical minerals are abundant in extraterrestrial bodies, and the possibility of extracting resources from in space is now closer to reality than ever. With the potential to avoid many of the risks associated with their supply on Earth, combined with the current push towards renewable energy; an evaluation of extraterrestrial bodies as a resource to meet the demand for critical minerals is timely. A set of eight critical minerals/mineral groups used in the manufacture of renewable energy technologies were identified in this study through an extensive literature review: lithium, gallium, selenium, silver, indium, tellurium, rare earth elements, and platinum. The potential of extraterrestrial bodies, namely the Moon and near-Earth asteroids, as a source of these critical minerals is investigated. We find that asteroids are likely to provide an important source of platinum, selenium, and gallium, and to a lesser extent, of silver, indium and tellurium. The case for extracting lithium and the rare earth elements from extraterrestrial bodies is less compelling. It is clear from this study that a reduction in the environmental and social impacts of producing these critical minerals is necessary. A strategy to extract minerals from extraterrestrial bodies would be a valuable step in achieving this.