Should a US national critical minerals reserve program act more like the National Defense Stockpile or more like the Strategic Petroleum Reserve? A major new report by my team does a deep dive into this question, looking at 15 minerals relevant to energy. My thoughts🧵:

RT @Dr_A_Stein: Here in western PA, not far from the pictured USS plant, you can still find high grade metallurgical coal just laying on th….

Check out @PeterCookBTI excellent piece here, written in an FAQ format that answers all your questions about what metallurgical coal is, how much met coal the US produces, who uses US-produced met coal, and much more:.

Three things can be true at once, via @PeterCookBTI:.1. the metallurgical coal subsidy probably makes life harder for American steel producers, not easier. 2. the subsidy's $190 million/year spend would be far more valuable if aimed at more urgent critical mineral projects.3.

RT @PeterCookBTI: The One Big Beautiful Bill Act phased out tax credits for critical minerals and gave them to metallurgical coal—which the….

So not an earth-shattering paper showing hard mineral constraints to energy transition imo, but still useful work worth reading critically. My impression as a reviewer was the authors wanted the headline that all 557 scenarios yield shortages. (END).

Maybe we pay more attention to tin and silver moving forwards, and this work certainly re-emphasizes the importance of effectively recycling materials like silver or lithium from end-of-life tech at sufficiently high purity.

So overall, I don’t think this @NatureClimate paper changes my working belief that energy transition minerals are more than sufficient for global decarbonization. The thin-film materials in particular really aren’t a key constraint.

Meanwhile sodium-ion batteries may claim more of the battery market share in the future, substituting lithium demand. And battery graphite material can be produced through synthetic approaches without relying on natural graphite mining.

Many regions of the world particularly Africa remain incompletely surveyed for mineral deposits, and by 2075 or 2090 it is more likely than not that technology will have advanced sufficiently for sustainable metals harvesting from the sea if not even space.

But the human history of lithium exploration and extraction is still young. Major new lithium deposits have been discovered in just the past 5-10 years, and both brine and hardrock resources are probably far from fully explored.

The latest @IEA critical minerals outlook highlights production of lithium along with copper as two of the potentially constraining energy transition mineral factors in the medium term (to 2035-2045).

Note this study didn't cover EVs. My team’s own work suggests EVs may drive >1/2 of energy transition demand for metals like nickel/copper, and EVs will consume 8-9 units of battery materials like lithium, graphite for every unit of grid battery storage.

I also do find it an interesting result that the magnitude of solar deployment through 2100 is what poses the largest challenge to mineral resources. Uncertainty aside, in critical minerals terms it is worth recognizing how much solar could be deployed between 2050-2100.

These applications have substitutes (alternative solders for tin-lead, electroplated copper for silver) but not without some potential cost/performance tradeoffs. I am taking away from this paper the thought that we perhaps ought to pay more attention to tin.

Now, I do think the projected shortages by 2100 for tin and silver (more driven by conventional silicon PV) are more interesting findings from this study. In manufacturing solar modules, tin is used in lead-tin solder and silver for metallization pastes.

As the authors acknowledge, uncertainties with projecting mineral intensity/demand in clean energy tech through 2100 are vast. Most studies stop calculating at 2050 or 2060, because who knows what a solar panel of 2080 will look like, or how much geothermal/fusion we’ll have.

So by and large, many of the @NatureClimate paper’s mineral shortages are driven by the massive projected deployment of solar PV over the next 75+ years to 2100, which drives fairly high adoption of thin-film solar PV consuming In, Cd, Ge, Te.

Silver-indium-cadmium alloys for nuclear control rods are common, but so too are boron carbide control rods. Fukushima Daiichi for ex used boron carbide (worked as designed, not at fault for accident). Boron carbide just needs more frequent replacement.

According to the latest Fraunhofer ISE solar industry report, standard crystalline silicon solar PV was 98% of the global market in 2024. The Wei et al paper assumed c-Si solar PV as 95.4% of the global market. Usage of thin-film PV minerals is very sensitive to this assumption.

In + Ge are used in copper indium gallium selenide (CIGS) thin-film solar PV. Cd + Te are used in cadmium telluride (CdTE) thin-film PV. Germanium is also used in advanced semiconductor chips, and indium and cadmium also see use in some control rods used in nuclear reactors.