3 ms·

I would think that having a battery based train engine, that can use electricity where available and use batteries where tract electrification is not done is be

I would think that having a battery based train engine, that can use electricity where available and use batteries where tract electrification is not done is better than fuel based ones, no matter the source or type of fuel.

dragontamer 4y ago
What if the Hydrogen fuel was made by electricity, and the Hydrogen was used in a Fuel Cell to generate electricity? Then you have effectively a full electric train, powered by Hydrogen Fuel Cells. This is superior because Hydrogen has far higher weight-density, so the train can travel further than if it had the much heavier Li-ion batteries to store and use electricity.
- adrian_b 4y ago
  The locomotives are made intentionally much heavier than they could be made. The weight of batteries cannot be a problem and any energy used to accelerate a higher mass is recovered. The energy storage cycle using hydrogen has a much lower efficiency than batteries, even when a fuel cell is used. Using hydrogen would make much more sense as a means for energy storage in an off-road vehicle than in trains, where the weight is irrelevant and the efficiency of the energy storage cycle is much more important, due to the very high energy consumption of a train. However, for other kinds of vehicles than trains, there are many kinds of synthetic fuels which are more difficult to make than hydrogen, but which are much easier to handle and store.
  - dragontamer 4y ago
    > The locomotives are made intentionally much heavier than they could be made. The weight of batteries cannot be a problem and any energy used to accelerate a higher mass is recovered. Hydrogen storage technology can fit 30MW-hrs of electricity in a standard semi-truck today (aka: 900kg of pressurized H2), and liquid-hydrogen cryogenics are coming around that fits far, far more energy in much denser packages. How many Li-ion batteries do you need to store 30MW-hrs? 1/10th of this won't fit on a train ya know: https://www.teslarati.com/tesla-megapacks-300mw-victoria-battery-video/ https://www.teslarati.com/tesla-megapacks-300mw-victoria-bat...
    - adrian_b 4y ago
      You are right about the lower energy density of batteries, but in the same space where you can store 30 MWh of hydrogen you can store much more energy as diesel fuel. So that is not an argument in favor of using hydrogen, that is an argument in favor of using the traditional diesel-electric locomotives.
      - dragontamer 4y ago
        1. Green H2 production needs to happen so that we get our fertilizers off of fossil fuels. The "greenification" of H2 / Ammonia / Fertilizer is one of the most important tasks of the near future, regardless of the energy / fuel issue. 2. Once we've stockpiled large amounts of H2, and created H2 pipelines to support the Fertilizer industry, we will gain the opportunity to use that H2 as transportation as well. 3. H2 to Syngas to Kerosene (or other hydrocarbons) are additional hits to efficiency. Electricity to H2 to electricity is some 40% efficient. But electricity to H2 to Syngas to Kerosene to ICE engine is like 1% efficient at best. Maybe in the future, the H2 + CO2 Syngas -> Hydrocarbon chemistries can be made more efficient? But its not looking good for modern technology. ------- "Green" energy is going to be harder than just slurping up pre-made hydrocarbons in the ground. But we've got like, climate-change issues, pollution, and other such issues we're trying to deal with? Diesel does work, and trains are rather efficient. But still, they're a good use case (large enough for H2 tanks), that H2 is likely a good fit. Might as well cut out the carbon emissions where it is easiest. It probably will be easier to convert trains to H2 Fuel cells rather than Cars to EV / Li-ion.
jillesvangurp 4y ago
Those trains already exist. Germany is also testing battery electric trains: https://www.alstom.com/press-releases-news/2022/1/alstom-and-deutsche-bahn-test-first-battery-train-passenger-operation https://www.alstom.com/press-releases-news/2022/1/alstom-and... Hydrogen cost is going to be decisive. Right now most hydrogen is produced using natural gas (so called grey hydrogen). Green hydrogen production with renewables is only happening on a small scale and is typically still more expensive than grey hydrogen. Long term (decades) this might become the cheapest and dominant way to produce hydrogen though. But for now, it's not an option for most hydrogen consumers. Blue hydrogen (grey with carbon capture) is something oil and gas companies love talking about but otherwise is not something that seems to be implemented at scale in the real world by anyone. And that too is going to be more expensive than grey hydrogen as it is basically the same process plus cost for capturing carbon. So, as gas prices are high right now and there's a shortage. Hydrogen prices are going to be higher and using it for transport is not going to have a high priority. And when it comes to efficiency, you are actually better off just burning natural gas as fuel than using it to produce hydrogen. You release less CO2, the emissions aren't that bad, and it's a much more efficient way to use the gas. So, these hydrogen trains are anything but green or affordable right now. They would be nice if we had cheap green hydrogen. But we don't just yet. And we probably won't have that for quite some time. So, yes, battery electric trains are the obvious move from a cost point of view. The charging infrastructure is already there. Just ride the train onto any rail segment that is electrified and take some juice in. It's probably not a whole lot more complicated than that. And you could electrify rails around e.g. stations so trains can charge while they stop there.

dragontamer 4y ago

What if the Hydrogen fuel was made by electricity, and the Hydrogen was used in a Fuel Cell to generate electricity? Then you have effectively a full electric train, powered by Hydrogen Fuel Cells. This is superior because Hydrogen has far higher weight-density, so the train can travel further than if it had the much heavier Li-ion batteries to store and use electricity.

adrian_b 4y ago
The locomotives are made intentionally much heavier than they could be made. The weight of batteries cannot be a problem and any energy used to accelerate a higher mass is recovered. The energy storage cycle using hydrogen has a much lower efficiency than batteries, even when a fuel cell is used. Using hydrogen would make much more sense as a means for energy storage in an off-road vehicle than in trains, where the weight is irrelevant and the efficiency of the energy storage cycle is much more important, due to the very high energy consumption of a train. However, for other kinds of vehicles than trains, there are many kinds of synthetic fuels which are more difficult to make than hydrogen, but which are much easier to handle and store.
- dragontamer 4y ago
  > The locomotives are made intentionally much heavier than they could be made. The weight of batteries cannot be a problem and any energy used to accelerate a higher mass is recovered. Hydrogen storage technology can fit 30MW-hrs of electricity in a standard semi-truck today (aka: 900kg of pressurized H2), and liquid-hydrogen cryogenics are coming around that fits far, far more energy in much denser packages. How many Li-ion batteries do you need to store 30MW-hrs? 1/10th of this won't fit on a train ya know: https://www.teslarati.com/tesla-megapacks-300mw-victoria-battery-video/ https://www.teslarati.com/tesla-megapacks-300mw-victoria-bat...
  - adrian_b 4y ago
    You are right about the lower energy density of batteries, but in the same space where you can store 30 MWh of hydrogen you can store much more energy as diesel fuel. So that is not an argument in favor of using hydrogen, that is an argument in favor of using the traditional diesel-electric locomotives.
    - dragontamer 4y ago
      1. Green H2 production needs to happen so that we get our fertilizers off of fossil fuels. The "greenification" of H2 / Ammonia / Fertilizer is one of the most important tasks of the near future, regardless of the energy / fuel issue. 2. Once we've stockpiled large amounts of H2, and created H2 pipelines to support the Fertilizer industry, we will gain the opportunity to use that H2 as transportation as well. 3. H2 to Syngas to Kerosene (or other hydrocarbons) are additional hits to efficiency. Electricity to H2 to electricity is some 40% efficient. But electricity to H2 to Syngas to Kerosene to ICE engine is like 1% efficient at best. Maybe in the future, the H2 + CO2 Syngas -> Hydrocarbon chemistries can be made more efficient? But its not looking good for modern technology. ------- "Green" energy is going to be harder than just slurping up pre-made hydrocarbons in the ground. But we've got like, climate-change issues, pollution, and other such issues we're trying to deal with? Diesel does work, and trains are rather efficient. But still, they're a good use case (large enough for H2 tanks), that H2 is likely a good fit. Might as well cut out the carbon emissions where it is easiest. It probably will be easier to convert trains to H2 Fuel cells rather than Cars to EV / Li-ion.

jillesvangurp 4y ago

Those trains already exist. Germany is also testing battery electric trains: https://www.alstom.com/press-releases-news/2022/1/alstom-and-deutsche-bahn-test-first-battery-train-passenger-operation https://www.alstom.com/press-releases-news/2022/1/alstom-and... Hydrogen cost is going to be decisive. Right now most hydrogen is produced using natural gas (so called grey hydrogen). Green hydrogen production with renewables is only happening on a small scale and is typically still more expensive than grey hydrogen. Long term (decades) this might become the cheapest and dominant way to produce hydrogen though. But for now, it's not an option for most hydrogen consumers. Blue hydrogen (grey with carbon capture) is something oil and gas companies love talking about but otherwise is not something that seems to be implemented at scale in the real world by anyone. And that too is going to be more expensive than grey hydrogen as it is basically the same process plus cost for capturing carbon. So, as gas prices are high right now and there's a shortage. Hydrogen prices are going to be higher and using it for transport is not going to have a high priority. And when it comes to efficiency, you are actually better off just burning natural gas as fuel than using it to produce hydrogen. You release less CO2, the emissions aren't that bad, and it's a much more efficient way to use the gas. So, these hydrogen trains are anything but green or affordable right now. They would be nice if we had cheap green hydrogen. But we don't just yet. And we probably won't have that for quite some time. So, yes, battery electric trains are the obvious move from a cost point of view. The charging infrastructure is already there. Just ride the train onto any rail segment that is electrified and take some juice in. It's probably not a whole lot more complicated than that. And you could electrify rails around e.g. stations so trains can charge while they stop there.