5 ms·

The first ocean-going steamships still had sails - it took many years for steam power to fully displace sail. Presumably a new maritime power system, like fusio

by jimbru 2y ago

The first ocean-going steamships still had sails - it took many years for steam power to fully displace sail. Presumably a new maritime power system, like fusion, would follow a similar pattern. https://en.wikipedia.org/wiki/Steamboat#Sea-_and_Ocean-going https://en.wikipedia.org/wiki/Steamboat#Sea-_and_Ocean-going

simpaticoder 2y ago
There is something very compelling about a fusion-powered ship also having sails.
- usrusr 2y ago
  Let's be realistic, it would have a diesel engine as a plan B. But if you like sails: my pet hypothetical technology is wind-driven hydrogen tankers (or tankers for some other e-fuel derived from hydrogen) that sail out empty, then cruise around wherever there is plenty of wind. They'd have a turbine/generator setup driven by the water passing by and use the energy harvested there for filling the tank. Cruise around as long as it takes to nearly fill the tank then return to port (and fill the rest on the way back). There's a lot of oceans where systems like that could cruise around on. (same concept could also be used for desalonation, there it would not only be about energy but also about avoiding local brine concentrations)
  - joss82 2y ago
    Interesting concept. Let's run the numbers... The largest Q-Max-class gas tanker is 345 meters long [1]. Let's say you manage to fit 3 giant Siemens wind turbines on it, with 100m long blades [2]. It's a bit cramped but let's say you have extenders on the side to make room for all 3 of them. And also let's say you found a way to prevent the ship from tipping over when the wind is strong. By deploying floaters on the side or whatever. Not unsurmountable. Each of those wind turbine has a rated power of 14.7 MW [2]. Let's say that you found a place where the wind blows super strong (but not too strong) and steady all the time. It's possible, since you are a mobile ship, after all. Let's say that you have a way for the ship to keep in the same place despite the strong and steady wind pushing you constantly. Using engines is going to lower your efficiency, so let's say we found another way. So, now your ship is generating 45MW constantly. According to ChatGPT, this is 32 kg of hydrogen per second, taking hydrolysis losses into account. Tanker capacity is 18 620 000 kg of liquid hydrogen. It will take 581 000 seconds to fill up. 9697 minutes, 161 hours, or 6.7 days. Much shorter than I thought... Did I miss something? [1] https://en.wikipedia.org/wiki/Q-Max https://en.wikipedia.org/wiki/Q-Max [2] https://www.offshorewind.biz/2024/04/22/first-siemens-gamesa-14-7-mw-turbine-stands-at-moray-west-offshore-wind-farm/ https://www.offshorewind.biz/2024/04/22/first-siemens-gamesa...
    - Earw0rm 2y ago
      It strikes me that having the turbine and hydrolysis plant fixed in place, and having ships visit those sites to refuel, is probably an easier setup than mobile turbines. But I think your maths is wrong somewhere. Hydrogen supplies 33MWh/tonne, and you've stated the ship capacity as 18620 tonnes. 18620/(33*24) gives a generation time of 23 days, even before we allow for hydrolysis overheads. Marine hydrogen isn't a terrible idea though. Tank weight and bulk is prohibitive for aviation, but less so for shipping.
      - Earw0rm 2y ago
        Ugh, turns out I suck at math too. At least attempting it before coffee. The ship's capacity in MWh is 18620t x 33MWh/t = 614460MWh. At 45MW generating capacity, an electric hydrolyser at 80% efficiency delivers hydrogen at a rate of 36MW. That will unfortunately take about 70 years to fill the ship to its maximum capacity. On a more positive note, 36MW is still a heck of a lot of power, plenty enough to run a mid-sized cruise liner or warship. So a marine generating station with three of these turbines could, for example, refuel a liner once a month, and then that liner have enough fuel to cruise for a month, and so on. This would require a fuel tank with a more reasonable 750 tonne capacity. That's still several times more than the Shuttle, but not beyond the realms of feasibility - and a stronger, heavier tank allows higher pressures / smaller volumes.
        ccozan 2y ago
        I am totally mesmerized by the idea of a floating hydrolizing platform , where ships can dock and load hydrogen fuel ( not sure what form suits best ). Must start some economics of it. Also marine environment is very unforgiving...
        Earw0rm 2y ago
        It is. But if we can handle maritime oil and gas rigs, which load/unload to tankers, hydrogen isn't MUCH worse. It wouldn't be floating exactly though. Moored and piled into the sea bed, sitting above the waves like rigs and wind turbines.
  - dredmorbius 2y ago
    Or bunker oil. But yes, fuel-based powerplant, likely as part of a hybrid drive running electric motors powering propellers themselves. Marine propulsion is already pretty optimised for efficiency (turn on engine, set to cruise power, maintain for 14 days, little acceleration, starts, stops, and/or hills), so a hybrid setup would work pretty effectively. The far greater challenges are Q>1 and reliable fusion within a ship's structure.
- throwawaymaths 2y ago
  sails on modern cargo ships is a thing (see pyxis ocean)

by jimbru 2y ago

simpaticoder 2y ago

There is something very compelling about a fusion-powered ship also having sails.

usrusr 2y ago
Let's be realistic, it would have a diesel engine as a plan B. But if you like sails: my pet hypothetical technology is wind-driven hydrogen tankers (or tankers for some other e-fuel derived from hydrogen) that sail out empty, then cruise around wherever there is plenty of wind. They'd have a turbine/generator setup driven by the water passing by and use the energy harvested there for filling the tank. Cruise around as long as it takes to nearly fill the tank then return to port (and fill the rest on the way back). There's a lot of oceans where systems like that could cruise around on. (same concept could also be used for desalonation, there it would not only be about energy but also about avoiding local brine concentrations)
- joss82 2y ago
  Interesting concept. Let's run the numbers... The largest Q-Max-class gas tanker is 345 meters long [1]. Let's say you manage to fit 3 giant Siemens wind turbines on it, with 100m long blades [2]. It's a bit cramped but let's say you have extenders on the side to make room for all 3 of them. And also let's say you found a way to prevent the ship from tipping over when the wind is strong. By deploying floaters on the side or whatever. Not unsurmountable. Each of those wind turbine has a rated power of 14.7 MW [2]. Let's say that you found a place where the wind blows super strong (but not too strong) and steady all the time. It's possible, since you are a mobile ship, after all. Let's say that you have a way for the ship to keep in the same place despite the strong and steady wind pushing you constantly. Using engines is going to lower your efficiency, so let's say we found another way. So, now your ship is generating 45MW constantly. According to ChatGPT, this is 32 kg of hydrogen per second, taking hydrolysis losses into account. Tanker capacity is 18 620 000 kg of liquid hydrogen. It will take 581 000 seconds to fill up. 9697 minutes, 161 hours, or 6.7 days. Much shorter than I thought... Did I miss something? [1] https://en.wikipedia.org/wiki/Q-Max https://en.wikipedia.org/wiki/Q-Max [2] https://www.offshorewind.biz/2024/04/22/first-siemens-gamesa-14-7-mw-turbine-stands-at-moray-west-offshore-wind-farm/ https://www.offshorewind.biz/2024/04/22/first-siemens-gamesa...
  - Earw0rm 2y ago
    It strikes me that having the turbine and hydrolysis plant fixed in place, and having ships visit those sites to refuel, is probably an easier setup than mobile turbines. But I think your maths is wrong somewhere. Hydrogen supplies 33MWh/tonne, and you've stated the ship capacity as 18620 tonnes. 18620/(33*24) gives a generation time of 23 days, even before we allow for hydrolysis overheads. Marine hydrogen isn't a terrible idea though. Tank weight and bulk is prohibitive for aviation, but less so for shipping.
    - Earw0rm 2y ago
      Ugh, turns out I suck at math too. At least attempting it before coffee. The ship's capacity in MWh is 18620t x 33MWh/t = 614460MWh. At 45MW generating capacity, an electric hydrolyser at 80% efficiency delivers hydrogen at a rate of 36MW. That will unfortunately take about 70 years to fill the ship to its maximum capacity. On a more positive note, 36MW is still a heck of a lot of power, plenty enough to run a mid-sized cruise liner or warship. So a marine generating station with three of these turbines could, for example, refuel a liner once a month, and then that liner have enough fuel to cruise for a month, and so on. This would require a fuel tank with a more reasonable 750 tonne capacity. That's still several times more than the Shuttle, but not beyond the realms of feasibility - and a stronger, heavier tank allows higher pressures / smaller volumes.
      - ccozan 2y ago
        I am totally mesmerized by the idea of a floating hydrolizing platform , where ships can dock and load hydrogen fuel ( not sure what form suits best ). Must start some economics of it. Also marine environment is very unforgiving...
        Earw0rm 2y ago
        It is. But if we can handle maritime oil and gas rigs, which load/unload to tankers, hydrogen isn't MUCH worse. It wouldn't be floating exactly though. Moored and piled into the sea bed, sitting above the waves like rigs and wind turbines.
- dredmorbius 2y ago
  Or bunker oil. But yes, fuel-based powerplant, likely as part of a hybrid drive running electric motors powering propellers themselves. Marine propulsion is already pretty optimised for efficiency (turn on engine, set to cruise power, maintain for 14 days, little acceleration, starts, stops, and/or hills), so a hybrid setup would work pretty effectively. The far greater challenges are Q>1 and reliable fusion within a ship's structure.
throwawaymaths 2y ago
sails on modern cargo ships is a thing (see pyxis ocean)