Critical mineral densities across technologies

Below is a research paper that I wrote for 22.103 (Nuclear society and technology), a required class for the PhD degree.

From the introduction of the paper:

In Revolutionary Power: An activist's guide to the energy revolution, Shalanda Baker---American legal scholar, U.S. Air Force veteran, and former director of the Office of Economic Impact and Diversity at the US Department of Energy for the Biden administration---argues that the clean-energy transition is not inherently just and that the transition will absorb the extractivism and inequity of the fossil-fuel era if we do not interrogate and rectify the systemic failures of our energy infrastructure [Source in pdf]. Non-fossil fuel energy technologies promise decarbonization, but they can still rely on environmental resources, including mineral supply chains, which are not reflected in carbon accounting---creating harms that often originate in communities already overburdened by ecological damage and political marginalization [Source in pdf]. As Baker emphasizes, energy systems are not neutral: they are social infrastructures drowned in histories of power, coloniality, racism, and uneven development. The minerals that underlie solar photovoltaics, wind turbines, batteries, and fission reactors are sourced through international supply chains marked by extreme concentration and asymmetry: cobalt from the Democratic Republic of Congo [Source in pdf], lithium from the Andean salt flats [Source in pdf], rare earths refined predominantly in China [Source in pdf]. Before committing to further large-scale deployment of these technologies, it is therefore essential to interrogate the density and supply chain of the critical minerals they require. Mineral intensity determines not only technical scalability but also the social and ecological footprint of extraction. By analyzing critical mineral density across energy technologies, we can align our build-out of energy sources with Baker’s call for an energy transition that centers equity, community consent, and environmental justice.

In order to even continue the conversation on critical mineral governance as it relates to the clean energy transition, we need to compare the mineral densities of renewable energy technologies and try to understand how the criticalities of elements across technologies compare. Previously, a 2021 study by the International Energy Agency compared the critical mineral densities (in kg/MW) across wind, solar, fission, coal, and gas [Source in pdf]. However, comparing critical mineral densities in units of $kg/MW$ can obscure the density of critical minerals across the lifetime production of energy of a system. Furthermore, the IEA study did not analyze the criticality of the individual elements used in technologies or include aluminum and steel in the calculations.

Here I compare the criticality of elements used in wind, solar, and fission technologies using an analytical model that takes into account the lifetime of an energy system, its capacity factor, and the criticality of each element as based on the Yale Criticality Framework. I find that certain critical elements like manganese and chromium (in wind and fission energy) and silver (in solar energy), though not used in high fractions, pose development risks to these technologies respectively. Fission and solar stand out over wind as two technologies that use the least amount of critical elements over their lifetime megawatt (MW) production. Though the Yale Criticality Framework does not consider environmental justice and just governance, my study serves as a starting point to disentangle the multidimensional pressures involved in critical mineral mining for wind, solar, and fission technologies.

Paper linked here