[srejk]

There are legitimate use cases for hydrogen. Trains are a good example - electrification of medium to long distances (through tough terrain) is prohibitively expensive, as is battery usage for the whole journey.

Trains require a lot of energy to get started (where batteries work well), but then a relatively small trickle of power is needed: hydrogen fills this niche. Big companies are investing billions into this right now.

[bryanlarsen]

Trains are a silly use case for hydrogen. Electric trains have been used and viable for approximately 100 years. The only problem is how expensive it is to electrify thousands of miles of tracks.

That problem is now gone, batteries can be used to bridge gaps in the catenary wires.

[srejk]

Think mountain passes or similarly difficult terrain. Or lower volume cargo trains, like into and out of industrial areas in the north. Catenary networks not only take a lot of money to set up, the maintenance is huge - especially in rough terrain or over long distances!

ed: Not saying that all trains should be hydrogen, there just are use cases for some when we're talking zero-emission.

[_hypx]

For tracks that cannot justify the cost of electrification, you will want hydrogen trains. Battery trains make the least sense, since it is easier to electrify those short gaps than to buy an entire new class of locomotives.

[pencilguin]

Power cables are an attractive theft target, many places.

An extra insulated car filled with lightweight LH2 would not appreciably increase the cost of operating a train.

Liquified ammonia under low pressure might be more practical, if safety worries don't dominate. We already move tanks of ammonia on trains. And much worse.

[bryanlarsen]

Liquid green hydrogen costs an order of magnitude more than electricity, and always will since it's created from electricity and uses electricity for liquification. It definitely will appreciably increase the cost of operating a train.

[pencilguin]

The weight of one extra car will increase the operating cost of a 100-car train by 1%, give or take a bit. Using cheap hydrogen instead of expensive kerosene may save much more than that. Moving light hydrogen instead of heavy kerosene may save more than that.

If the electricity could be delivered directly to the train, the energy used would be cheaper, but installing (and replacing "shrinkage" of) many thousands of miles of "third rail" would cost a lot.

The hydrogen is not yet cheaper than the kerosene, but costs on that side are falling fast.

[bryanlarsen]

You don't need thousands of miles of third rails or catenary wires. Just a ~mile every ~hundred, and a battery on the locomotive.

[pencilguin]

That is an interesting alternative.

You need a battery that tolerates many many cycles, and being charged at 100x its usual discharge rate. Maybe a molten CaSb battery, from Ambri.

I guess if all the cars can be wired to take in power, you just need a short stretch of 3rd rail at each charge point, say 60 m, not 1600. If each car has its own battery and drive motors, they don't need to be wired together. Relative charge rate goes to 10,000x, but the grid load stays the same.

[giarc]

Wouldn't large container ships and trains be the perfect candidates for electrification? Create some sea can sized batteries that can easily be loaded on to and off of the train/ship. The infrastructure already exists for loading them, and they are used to carrying sea cans already. As I understand, ships are huge carbon emitters so if you could load a dozen sea can sized batteries, perhaps it could power it across the Atlantic (or maybe it would take a 1000 sized batteries, which would make it impractical).

[dontlaugh]

Electrification of existing lines and even new high speed lines are both much cheaper than the cars and fuel they can replace.

[Vvector]

Maybe we could power the trains along the rail, or in catenary above? Add a very small battery to power it maneuvering around the rail yard?

[Kuinox]

How do you restart the train after stopping in the middle of nowhere ?

[kobalsky]

hydrogen generators?