3 ms·

Is a tendency to miss some practical concerns the same as "physics defying" or have you just completely shifted arguments without acknowledging that your former

Is a tendency to miss some practical concerns the same as "physics defying" or have you just completely shifted arguments without acknowledging that your former one was completely fabricated and anti-scientific? What does your number have to do with the practicality of the prospects of electric container ships? You threw out a number, now justify what you think that means. A big number is supposed to do what?

olivermarks 4y ago
Do the math - container ships carry literally million of gallons of fuel to propel themselves through the ocean with enough spare to deal with inclement conditions, storms etc. A truck carries a rolling load, meaning once they are up and rolling the engine doesn't have to work as hard on a flat surface, boat propellors are continuous load. What battery technology exists today that could even begin to store and deliver the amount of energy needed reliably, how long would they take to charge up? I suspect the size of the batteries would look like a fully loaded container ship. This isn't 'anti scientific' it's a common sense practical rebuttal of a pseudo scientific/academic fantasy world
- epistasis 4y ago
  You are responding to an entire article all about the math. That you did not read. And dismiss because you apparently know better without even bothering to know what they are proposing. There is nothing more anti-scientific than that. You are not even making a basic effort to understand what you are criticizing.
  - olivermarks 4y ago
    Oh I read it... ....We assume an ICE tank-to-wake efficiency of 50% and electric motor and inverter efficiencies of 95% each28. Batteries yield an 80% efficiency improvement compared to their ICE counterparts, which translates to a 30% decrease in total energy needs for the battery-electric ship….We assume a containership carries enough fuel for a day’s voyage; in reality, this figure is probably higher, because ships often carry fuel for several days after bunkering… Most of the initial asssumptions are way off and rely on the 'tightening regulatory landscape' to make hte battery powered fantasy more convincing. Discuss this with anyone in shipping and they will just laugh
    - shkkmo 4y ago
      If you have issues with specific assumptions and sources to cite showing how those assumptions are flawed, then you would be contributing to a productive conversation about the article. Simply saying "Batteries are really heavy and will be exhausted of power very quickly by the continuous load from underwater propellor propulsion." when those specific points have been discussed in the article does not contribute anything to the discussions and simply makes it appear as if you did not read the article.
    - markdestouches 4y ago
      Could you, please, elaborate what realistic assumptions would look like? I am not in shipping industry nor am I a battery expert. I understand that batteries suffer from lower energy density and a number of other issues, but I'd really like to see how far off the tech is numerically.
      - snovv_crash 4y ago
        As a start, they need a few weeks of fuel, not a day. Also, large ICEs are actually a lot more efficient than the little things we put in cars. Bunker fuel is also enormously cheaper than regular gasoline. The overall takeaway for me is that we need a 10x improvement in battery density, electricity costs to be 1/3 of today, plus a 30x reduction in battery costs, for this to be feasible. At that point, it is 'just' a capex problem to replace the fleet. These are still 'decades away' numbers IMO.
10u152 4y ago
Your comment is somewhat hostile. "Justify what you think that means" OK. Well the large scale BES plants struggle to get costs below $200 per kWh. So that means that the cost for this battery is about $11,385,000,000. And this doesnt take into account the amount of space and weight this would take up on the ship. The cost of a panamax class appear to be about $300m. or about 38x increase in cost. This seems like a pretty clear case of it's not going to work.
- olivermarks 4y ago
  thank you @10u152
- shkkmo 4y ago
  And your reply doesn't take into account the cost saving from not buying fuel and not emitting pollution. Figure 3 from the article specifically looks at the relationship between battery cost and density vs voyage length on the cost effectiveness of switching. The article is analyzing balancing lifetime costs of the batteries and their recharging vs. the lifetime costs of fuel for an ICE powered ship.
  - 10u152 4y ago
    56 million kWh. At current Australian wholesale prices that's $17m AUD to refuel. Does that sound like a cheap tank of gas ?
    - epistasis 4y ago
      Well that depends, is that a representative price for electricity across ports? What is the representative price for equivalent heavy fuel oil? Yet again, stating a single big number with emphasis is no way to convince anybody of anything. What's the baseline? Or are people just supposed to be scared of big numbers and run away? This is yet again a highly unscientific way to think about a matter.
      - 10u152 4y ago

olivermarks 4y ago

Do the math - container ships carry literally million of gallons of fuel to propel themselves through the ocean with enough spare to deal with inclement conditions, storms etc. A truck carries a rolling load, meaning once they are up and rolling the engine doesn't have to work as hard on a flat surface, boat propellors are continuous load. What battery technology exists today that could even begin to store and deliver the amount of energy needed reliably, how long would they take to charge up? I suspect the size of the batteries would look like a fully loaded container ship. This isn't 'anti scientific' it's a common sense practical rebuttal of a pseudo scientific/academic fantasy world

epistasis 4y ago
You are responding to an entire article all about the math. That you did not read. And dismiss because you apparently know better without even bothering to know what they are proposing. There is nothing more anti-scientific than that. You are not even making a basic effort to understand what you are criticizing.
- olivermarks 4y ago
  Oh I read it... ....We assume an ICE tank-to-wake efficiency of 50% and electric motor and inverter efficiencies of 95% each28. Batteries yield an 80% efficiency improvement compared to their ICE counterparts, which translates to a 30% decrease in total energy needs for the battery-electric ship….We assume a containership carries enough fuel for a day’s voyage; in reality, this figure is probably higher, because ships often carry fuel for several days after bunkering… Most of the initial asssumptions are way off and rely on the 'tightening regulatory landscape' to make hte battery powered fantasy more convincing. Discuss this with anyone in shipping and they will just laugh
  - shkkmo 4y ago
    If you have issues with specific assumptions and sources to cite showing how those assumptions are flawed, then you would be contributing to a productive conversation about the article. Simply saying "Batteries are really heavy and will be exhausted of power very quickly by the continuous load from underwater propellor propulsion." when those specific points have been discussed in the article does not contribute anything to the discussions and simply makes it appear as if you did not read the article.
  - markdestouches 4y ago
    Could you, please, elaborate what realistic assumptions would look like? I am not in shipping industry nor am I a battery expert. I understand that batteries suffer from lower energy density and a number of other issues, but I'd really like to see how far off the tech is numerically.
    - snovv_crash 4y ago
      As a start, they need a few weeks of fuel, not a day. Also, large ICEs are actually a lot more efficient than the little things we put in cars. Bunker fuel is also enormously cheaper than regular gasoline. The overall takeaway for me is that we need a 10x improvement in battery density, electricity costs to be 1/3 of today, plus a 30x reduction in battery costs, for this to be feasible. At that point, it is 'just' a capex problem to replace the fleet. These are still 'decades away' numbers IMO.

10u152 4y ago

Your comment is somewhat hostile. "Justify what you think that means" OK. Well the large scale BES plants struggle to get costs below $200 per kWh. So that means that the cost for this battery is about $11,385,000,000. And this doesnt take into account the amount of space and weight this would take up on the ship. The cost of a panamax class appear to be about $300m. or about 38x increase in cost. This seems like a pretty clear case of it's not going to work.

olivermarks 4y ago
thank you @10u152
shkkmo 4y ago
And your reply doesn't take into account the cost saving from not buying fuel and not emitting pollution. Figure 3 from the article specifically looks at the relationship between battery cost and density vs voyage length on the cost effectiveness of switching. The article is analyzing balancing lifetime costs of the batteries and their recharging vs. the lifetime costs of fuel for an ICE powered ship.
- 10u152 4y ago
  56 million kWh. At current Australian wholesale prices that's $17m AUD to refuel. Does that sound like a cheap tank of gas ?
  - epistasis 4y ago
    Well that depends, is that a representative price for electricity across ports? What is the representative price for equivalent heavy fuel oil? Yet again, stating a single big number with emphasis is no way to convince anybody of anything. What's the baseline? Or are people just supposed to be scared of big numbers and run away? This is yet again a highly unscientific way to think about a matter.
    - 10u152 4y ago