Old:Fuel cell vehicles

Fuel cell electric vehicles, or FCEVs for short, are vehicles powered by hydrogen gas. The fuel cell component takes in hydrogen (H₂) and oxygen (O₂ from the air), and produces electricity to power the motor. The only exhaust is water vapor (H₂O).

Viability

It's uncertain whether this can be scaled up enough to replace even half of gasoline-powered vehicles.

Potential issues to be dealt with:

#Inefficient compared to batteries	Unavoidable but maybe manageable
#Rare minerals in the fuel cell	Might be impossible to solve
Energy to manufacture the fuel cell	Research needed
Safety	Mostly solved
Hydrogen fueling stations	Solvable
Storing enough fuel in the vehicle	Solved

Inefficient compared to batteries

Whether fuel cells or batteries, the intention is to power vehicles with green electricity.

Converting energy to hydrogen, then back to electricity again - is best-case only 40 to 48% efficient. (...)( 80% efficiency for hydrogen production, multiplied by 50% to 60% efficiency for the best fuel cells )
Whereas charging/discharging a lithium-ion battery - is 80% to 90% efficient.

In other words, with fuel-cell vehicles we would need twice as much green electricity!

It's already hard enough to meet energy demand with renewables as it is (hence most energy comes from fossil fuels currently). Hydrogen vehicles would make it somewhat harder. The good news is it's still more efficient than combustion engine vehicles (no matter the fuel).

Rare minerals in the fuel cell

Inside a fuel cell, there are surfaces coated in a thin layer of platinum, palladium, rhodium, and/or iridium. These are called platinum-group metals (PGMs) and are extremely scarce. PGMs are needed as a catalyst to make the hydrogen and oxygen to react properly.

The same metals are also in catalytic converters in gasoline and diesel vehicles, but in lesser quantities. A catalytic converter has about 2 grams of PGMs(...)( 2 grams for a typical car; large trucks have proportionally more ), while a fuel cell car has 30 to 60 grams(...)( Some scientists are working on reducing this amount, but it's hard to say how much progress can (or will) be made. ).

If all vehicles(...)( Is that too extreme a scenario? Then go with 'only half of all vehicles' and consider the numbers below to be the total PGM demand, assuming that an equal amount of PGMs are also needed for hydrogen production. ) were fuel cell-based,

The amount of PGMs needed is well within the limits of global mineral reserves.
The mining would take a very long time.
It helps slightly that PGMs can be recycled from old vehicle catalytic converters.

Some relevant calculations:

toyota_mirai.pgm

30 grams

Amount of platinum-group metals (PGMs) in a Toyota Mirai (fuel cell vehicle)

The Toyota Mirai is a common example of a hydrogen-powered vehicle.

https://www.heraeus.com/media/media/hpm/doc_hpm/precious_metal_update/en_6/20181031_PGM_Market_Analysis.pdf

catalytic_converter.pgm

2 grams

Platinum-group metals (PGMs) in a catalytic converter of a gasoline-powered car

Countless automotive forums say 3 to 7 grams for a typical car.

But ThermoFisher (which is more reputable, perhaps) says "The recoverable amounts of Pt, Pd, and Rh in each [vehicle] can range from 1-2 grams for a small car to 12-15 grams for a big truck in the US." - Are There Precious Metals in Catalytic Converters? https://www.thermofisher.com/blog/metals/platinum-group-metal-recovery-from-spent-catalytic-converters-using-xrf/

I assume they mean 1-2 grams ''total'', not 1-2 grams ''of each'' Pt Pd Rh, right? That would make sense considering they also mention that the ratios vary as metal prices/availability change over time.

1 to 2 grams total recoverable is also consistent with the following study: Yakoumis et al 2018 IOP Conf. Ser.: Mater. Sci. Eng. 329 012009 - Real life experimental determination of platinum group metals content in automotive catalytic converters - https://iopscience.iop.org/article/10.1088/1757-899X/329/1/012009/pdf

Still no word on what percentage this ''recoverable'' is of total PGMs - how efficient is the recycling process? Unknown

world.cars

1.446 billion

Number of cars in the world

Last updated in 2022
www.carsguide.com.au › car-advice › how-many-cars-are-there-in-the-wor...
hedgescompany.com › blog › 2021/06 › how-many-cars-are-there-in-the-...

pgm.reserves

70000 tonnes

Global reserves of platinum-group metals

Includes platinum, palladium, ruthenium, rhodium, osmium, iridium.

Platinum-group metal reserves worldwide by country 2021
Statista - https://www.statista.com › statistics › platinum-me...

platinum.mine_production

186000 kg/year

Global production of new platinum from mining

Using data from 2019.

Source: USGS Mineral Commodity Summaries 2021

palladium.mine_production

227000 kg/year

Global production of new palladium from mining

Using data from 2019.

Source: USGS Mineral Commodity Summaries 2021

pgm.mine_production

platinum.mine_production + palladium.mine_production

Global production of platinum-group metals (PGMs) from mining

Assumption: that the other PGMs (iridium, rhodium, osmium, ruthenium) are in such small quantities that it's ok that they aren't counted here (because data is unavailable)

% pgm.reserves new_pgm_needed (calculation loading) new_pgm_needed years pgm.mine_production (calculation loading) That's a long time - too long. Then again, suppose the mining industry were to hire 10 times as many people(...)( due to economics perhaps, if fuel cell vehicles did become a major market ), could it all be mined 10 times faster? Does mining work that way, or are there other bottlenecks?^{[RESEARCH needed]}

Keep in mind that a similar amount of PGMs would also be needed for green hydrogen production.

More data is needed:

How many human labor hours would it take to mine this much?
How much dirt would have to be dug out, and what would be the environmental impact?

If the answers are bleak, then the only hope is in designing fuel cells that contain no more PGMs than a catalytic converter (research?).

Viability

Inefficient compared to batteries

Rare minerals in the fuel cell

See also