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Hydrogen advocates have a behavior of ignoring the apparent constraint sitting on the core of their most popular expertise. They communicate of value declines, of economies of scale, and of inexperienced hydrogen pipelines, however not often acknowledge that the chemistry of proton trade membrane gasoline cells will depend on a scarce and irreplaceable metallic. In a latest article, I checked out Alstom’s hydrogen trains, which have been sidelined and pushed again to diesel as a result of Cummins couldn’t ship substitute gasoline cells. Following that thread again revealed that platinum shortages are on the coronary heart of the issue. The reality is that if a handful of trains run into hassle, the story solely will get worse while you think about hundreds of thousands of automobiles, vehicles, and buses relying on the identical scarce catalyst.
Platinum is the important thing to creating PEM gasoline cells work. It splits hydrogen molecules on the anode, permits protons via the membrane, and accelerates the gradual response that mixes oxygen with electrons and protons on the cathode. No platinum means no sensible gasoline cell. International platinum provide is about 250 to 280 tons per yr. Roughly a 3rd goes into automotive catalytic converters, one other quarter goes into jewellery, a few fifth goes into industrial catalysts, and the remaining is break up amongst glass, electronics, and some rising makes use of. The market is already in deficit, with shortfalls of about 30 tons a yr and inventories operating skinny. Costs have been climbing, and lease charges for bodily metallic have spiked. That’s the market context into which hydrogen for mobility is making an attempt to insert itself.
Electrolysis faces a special set of fabric challenges than gasoline cell autos as a result of not all electrolyser varieties depend upon platinum. Proton trade membrane electrolysers do use platinum and iridium on the electrodes, however their share of the market continues to be comparatively small in comparison with alkaline techniques, which depend on considerable supplies like nickel and iron. Stable oxide electrolysers keep away from platinum completely by working at excessive temperatures with ceramic supplies. Even inside PEM designs, platinum loadings are decrease than in heavy-duty transport stacks, and iridium shortage relatively than platinum is the principle bottleneck. Which means that whereas platinum provide can gradual the expansion of PEM electrolysis, the sector has technological alternate options that enable scaling with out being locked right into a single irreplaceable metallic. Gas cell autos wouldn’t have that flexibility.
To grasp the size of the issue, it’s value operating eventualities. A typical passenger gasoline cell automotive makes use of a stack of about 100 kW. At life like loadings of 0.13 to 0.18 g of platinum per kW, that’s 13 to 18 g of platinum per car. A heavy truck stack of 300 kW at 0.4 to 0.6 g per kW consumes 120 to 180 g of platinum. A bus stack of 100 to 150 kW consumes 40 to 90 g. If solely 10 % of worldwide car gross sales had been gasoline cell based mostly, that might require 159 to 226 tons of platinum per yr. That’s 60 to 90 % of all the world platinum market, leaving little or nothing for refining, diesel aftertreatment, or jewellery. A 50 % hydrogen car world would want round 800 to 1,100 tons per yr, whereas a 100% state of affairs would eat 1,600 to 2,300 tons yearly. Even the bottom state of affairs consumes almost the entire market.
These numbers change into extra vivid when transformed into geology. South African platinum ores typically comprise 2 to six g of platinum group metals per ton of rock. Trade metrics recommend 10 to 40 tons of ore should be processed to extract a single troy ounce of platinum. On that foundation, every ton of platinum requires the motion and processing of 320,000 to over 1.2 million tons of ore. On the low finish of the ten % hydrogen state of affairs, with demand of about 160 tons, the trade would want to mine and course of over 50 million tons of rock every year on high of right now’s manufacturing. On the higher finish, over 200 million tons of ore could be required. To place that in context, that’s extra rock than was excavated to construct the Panama Canal. It’s about half the annual quantity of iron ore mined in Australia. Scaling hydrogen transport means making an attempt so as to add a brand new mining trade the dimensions of the copper sector, however devoted completely to at least one scarce metallic.
Hydrogen advocates reply to this in a couple of predictable methods. They level out that platinum loadings have fallen by 80 % from the earliest stacks, which is true. They level to closed loop recycling applications that may get better 95 % of platinum from finish of life stacks, which is true in managed pilot circumstances. They spotlight analysis into PGM free catalysts and alkaline membranes, which is actual however not business. The issue is that none of those measures modifications the basic constraint. Heavy obligation stacks nonetheless want 0.4 to 0.6 g per kW for sturdiness, and shaving that quantity additional is troublesome. Recycling solely helps after a fleet has been constructed and retired, it doesn’t present the preliminary volumes wanted to scale. PGM free catalysts stay within the lab, and their efficiency and lifetimes have but to satisfy the necessities of heavy transport.
If hydrogen autos grabbed 10 % of the market, platinum demand would bounce by half. Market evaluation exhibits that platinum provide and demand are worth inelastic within the brief time period. A 50 % improve in demand in a deficit market with fastened provide is prone to double or triple the value. That may push platinum from $1,300 per ounce to $2,600 and even $3,900. At these costs, the platinum in a single passenger automotive stack would add $1,600 to $2,200 in value. In a heavy truck it might add $15,000 to $22,500. In a bus the rise could be $5,000 to $11,000. These prices come on high of the opposite disadvantages of gasoline cell autos in comparison with batteries, together with poor effectivity and better infrastructure prices.
Batteries should not with out their very own metallic necessities, however there isn’t any equal choke level. Nickel and cobalt might be prevented by shifting to LFP chemistries. Lithium might be prevented in some purposes by sodium ion. Manganese and iron are considerable. The constraints in batteries are round manufacturing unit construct out and provide chain group, not a single scarce and irreplaceable component. In platinum the hydrogen sector has no such escape hatch. With out platinum, PEM gasoline cells don’t operate, and there’s no life like substitute at scale.
This leads again to the query of honesty within the hydrogen narrative. Platinum shortages have been identified for years. Trade roadmaps acknowledge the issue however current targets and aspirations as in the event that they had been close to time period realities. The fact is that even modest adoption would eat the majority of the worldwide platinum market, require shifting mountains of rock, and drive platinum costs excessive sufficient to make hydrogen autos unaffordable. The Alstom trains already confirmed what occurs when the constraint bites. At world scale the issue is just not a technical hiccup however a basic restrict. Power transitions succeed when applied sciences can scale with considerable assets. Batteries meet that check. Hydrogen for street transport doesn’t.
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