Kinexity t1_iy4cybq wrote
Reply to comment by A40 in 'Landmark achievement': Rolls-Royce and easyJet hail successful hydrogen jet engine test by Wagamaga
Hydrogen is inefficient, hard to store/transport and requires complex infrastructure. Overhead electric is the best for trains.
A40 t1_iy54f5g wrote
Distances are different. Canada is thousands of miles across and very sparsely populated compared to Europe, for instance.
Overhead electric on 5,000+ km of freight rail? (That's as the crow flies.) Not at all practical.
[deleted] t1_iy5b2ef wrote
How much do you think gas pipelines cost to install and maintain?
A40 t1_iy5ej8z wrote
I was wondering about gas storage cars on the trains, like old-timey coal tenders. Liquid hydrogen tanks?
Vickrin t1_iy59co5 wrote
Do you know how much hydrogen you'd need to travel 5000kms?
Just put up some power lines...WAAAAY more practical.
myflippinggoodness t1_iy5b3py wrote
Can you feed the electrical system directly off the track? Then, any issues that would cause? Also, how's that holding up in Canadian winters?
Gah this seems tricky and costly but mby(?????) A good idea?? Fckn advanced shiprec is.. Advanced 🤦♂️
Vickrin t1_iy5cjcj wrote
Hydrogen is just a poor fuel compared to hydrocarbons.
Hydrogen takes up space and is heavy in the quantities you'd need.
Electricity is great because you don't need to ship it with your goods.
People trying to reinvent the train should just try trains first.
Japan has an amazing train network and yet nobody is copying them.
myflippinggoodness t1_iy5dy00 wrote
On Japan's trains--VERY TRUE, they have an awesome setup for densely populated urban areas.. but everything here is so spread out, and there's the weather to contend with too.. I mean, I'm thinking heavy supply transit more than just ppl transit.. ah fuck it, soup the shit outta Canada's current transcontinental rail systems. That's probably step 1
Vickrin t1_iy5epcy wrote
>but everything here is so spread out
Build longer tracks?
Japan's rail system covers the entire country. It's not just metro areas.
A40 t1_iy5ejua wrote
I was wondering about gas storage cars on the trains, like old-timey coal tenders. Liquid hydrogen tanks?
Vickrin t1_iy5ewxj wrote
Hydrogen is not energy dense, it would require extremely high pressure storage which is heavy as hell and expensive.
A40 t1_iy5fzn0 wrote
Diesel has an energy density of 45.5 megajoules per kilogram (MJ/kg), slightly lower than gasoline, which has an energy density of 45.8 MJ/kg. By contrast, hydrogen has an energy density of approximately 120 MJ/kg, almost three times more than diesel or gasoline. What this really means is that 1 kg of hydrogen, used in a fuel cell to power an electric motor, contains approximately the same energy as a gallon of diesel (rmi.org). site
As for storage weight: train, locomotive. Expensive: probably, until it's a mature industry.
Vickrin t1_iy5hgyq wrote
1kg of diesel can sit in a metal tank, at room temperature, no pressure needed.
Do you know how much space 1kg of hydrogen takes up?
Liquid hydrogen needs to be stored at -250c at 1 bar or more of pressure. This requires high strength storage. This means your 1kg of hydrogen ends up actually weighing a hell of a lot more than 1kg. Keeping it cool also requires energy which means you get even less out of your hydrogen fuel.
Sure you could store it as a gas but that would require 350-700 bar of pressure which requires even MORE expensive storage.
It's not as simple as the raw maths.
Can you imagine the damage if a train derailed with high pressure hydrogen tanks? Diesel doesn't explode and neither does electricity.
A40 t1_iy5nvj8 wrote
Thanks for the info!
So a hydrogen jet engine is... less than useless?
Vickrin t1_iy5ohqn wrote
Exploring the concept is never wasted, people might learn something.
Putting a hydrogen engine in an aircraft is not going to be a viable option for the forseeable future.
Aircraft are probably one of the hardest things to move to a green fuel source.
Batteries are also awful when it comes to aircraft.
Xe6s2 t1_iy5r1zo wrote
Plus hydrogen leaks the most out of all fuels. Magnetic bottles would work better imo.
Funktron3000 t1_iy6tud0 wrote
What if we just used it at lower pressures and filled blimps with it?
Vickrin t1_iy78740 wrote
What could go wrong?
lestofante t1_iy7knjd wrote
Not really, Remeber, the most powerful rocket are hydrogen+oxigen.
The bigger the amount you want to store, the less is the coat of the container, as container weight grow as square(perimeter), while volume contained grow as cube.
A hydrogen train make a lot of sense and they have been already successful experimented, but will never take off until cost of diesel is cheaper.
AzzaClazza t1_iy7zccq wrote
1kg of liquid hydrogen takes up 14L of volume, plus the tank itself.
Vickrin t1_iy98rkb wrote
And a tank that can hold hydrogen weighs a lot
Kinexity t1_iy5ayzf wrote
Two words: Transsiberian Railway
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