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I am really surprised that the mass and volume requirement for batteries are within the same order of magnitude as for bunker fuel for this task. I thought batt

by beAbU 11mo ago

I am really surprised that the mass and volume requirement for batteries are within the same order of magnitude as for bunker fuel for this task. I thought batteries were still lagging far behind! Is bunker fuel energy density just that bad or is it something else? A 50kg tank of diesel can easily outperform a 200kg pack of batteries in an ev.

rgmerk 11mo ago
Battery energy density is way behind that of bunker fuel, it’s just that cargo ships (at least as far as some googling suggests), have fuel capacity far in excess of what is required for a 5000km range.
- conk 11mo ago
  My guess is not every port can supply bunker fuel. It prob makes sense to load up when the ship is near a refinery and then make several trips before refueling.
  - closewith 11mo ago
    > My guess is not every port can supply bunker fuel. You can bunker anywhere, even at sea if you're willing to pay. Ships have large tanks to allow for economically advantageous bunkering at cheap and low-tax ports.
- acchow 11mo ago
  But 5000km is shorter than many major routes, right? Shanghai to Los Angeles is more than double that
  - Qwertious 11mo ago
    The route length isn't important, only the longest distance between ports that you can recharge at. Cargo ships regularly slow steam (I.e. run the engine slow to improve fuel-efficiency) and stopping to recharge batteries at multiple ports to reduce the batteries needed is the exact same concept - sacrificing speed to improve fuel costs. Shanghai to LA is probably the worst example (since the pacific ocean is basically the emptiest spot on the planet, as land/port frequency goes), but Hawaii still exists and they could recharge there.
    - stavros 11mo ago
      How does Hawaii produce its power? I can't imagine they have tons of capacity. EDIT: Seems like they mostly use imported oil, so saying "bring us a bunch of oil and we'll charge your batteries with it" seems like the ship is just burning oil with extra steps.
      - guttural 11mo ago
        I bet these batteries would be standard container sized and they could be shipped as normal containers would be wherever cheap power is available from nuclear or solar or maybe water. Australia could be huge here, back in 2024 there were news of a six gigawatt solar farm in remote Northern Australia. Based on my very vague knowledge of the geography I presume there's plenty more desert to build solar there. Charge the battery-containers, ship them to China.
        stavros 11mo ago
        Whatever they are, you can't say "how does the ship refuel when it's empty? I know, it'll carry its own extra fuel".
        guttural 11mo ago
        No, no you misunderstand, the ports will provide fuel in the form of charged battery containers and there will be runs solely to carry these charged batteries from wherever they can be charged cheap to ports where charging is expensive/unavailable. Los Angeles port already tries to achieve zero-emissions operations by 2030 I presume more solar could be added. And I guess some/many ports and Los Angeles specifically could use wave energy. But, again, I could very well imagine Northern Australia supply ports in Eastern Asia.
      - rgmerk 11mo ago
        I don’t understand why Hawaii doesn’t have more solar. Gotta be a lot cheaper than imported oil, even with the the US solar premium.
    - 11mo ago
- beAbU 11mo ago
  Ah, so what you are saying is we are not going to need to make significant compromises to the ship's cargo capacity, but we are impacting the total max range significantly? Is a fully fuelled ship capable of much more than 5k km?

by beAbU 11mo ago

rgmerk 11mo ago

Battery energy density is way behind that of bunker fuel, it’s just that cargo ships (at least as far as some googling suggests), have fuel capacity far in excess of what is required for a 5000km range.

conk 11mo ago
My guess is not every port can supply bunker fuel. It prob makes sense to load up when the ship is near a refinery and then make several trips before refueling.
- closewith 11mo ago
  > My guess is not every port can supply bunker fuel. You can bunker anywhere, even at sea if you're willing to pay. Ships have large tanks to allow for economically advantageous bunkering at cheap and low-tax ports.
acchow 11mo ago
But 5000km is shorter than many major routes, right? Shanghai to Los Angeles is more than double that
- Qwertious 11mo ago
  The route length isn't important, only the longest distance between ports that you can recharge at. Cargo ships regularly slow steam (I.e. run the engine slow to improve fuel-efficiency) and stopping to recharge batteries at multiple ports to reduce the batteries needed is the exact same concept - sacrificing speed to improve fuel costs. Shanghai to LA is probably the worst example (since the pacific ocean is basically the emptiest spot on the planet, as land/port frequency goes), but Hawaii still exists and they could recharge there.
  - stavros 11mo ago
    How does Hawaii produce its power? I can't imagine they have tons of capacity. EDIT: Seems like they mostly use imported oil, so saying "bring us a bunch of oil and we'll charge your batteries with it" seems like the ship is just burning oil with extra steps.
    - guttural 11mo ago
      I bet these batteries would be standard container sized and they could be shipped as normal containers would be wherever cheap power is available from nuclear or solar or maybe water. Australia could be huge here, back in 2024 there were news of a six gigawatt solar farm in remote Northern Australia. Based on my very vague knowledge of the geography I presume there's plenty more desert to build solar there. Charge the battery-containers, ship them to China.
      - stavros 11mo ago
        Whatever they are, you can't say "how does the ship refuel when it's empty? I know, it'll carry its own extra fuel".
        guttural 11mo ago
        No, no you misunderstand, the ports will provide fuel in the form of charged battery containers and there will be runs solely to carry these charged batteries from wherever they can be charged cheap to ports where charging is expensive/unavailable. Los Angeles port already tries to achieve zero-emissions operations by 2030 I presume more solar could be added. And I guess some/many ports and Los Angeles specifically could use wave energy. But, again, I could very well imagine Northern Australia supply ports in Eastern Asia.
    - rgmerk 11mo ago
      I don’t understand why Hawaii doesn’t have more solar. Gotta be a lot cheaper than imported oil, even with the the US solar premium.
  - 11mo ago
beAbU 11mo ago
Ah, so what you are saying is we are not going to need to make significant compromises to the ship's cargo capacity, but we are impacting the total max range significantly? Is a fully fuelled ship capable of much more than 5k km?