5 ms·

This is one of the endless physics defying articles implying 'acceleration' towards a fantasy all-electric future. Batteries are really heavy and will be exhaus

This is one of the endless physics defying articles implying 'acceleration' towards a fantasy all-electric future. Batteries are really heavy and will be exhausted of power very quickly by the continuous load from underwater propellor propulsion. A small nuclear reactor powered boat would work but the idea of battery powered container ships is specious at best.

epistasis 4y ago
> will be exhausted of power very quickly by the continuous load from underwater propellor propulsion. Sorry, this is your "physics"? Edit: just to be clear but there's an entire paper published in a high profile journal, peer-reviewed, and and the comment is "nuh uh" while appealing to non-existent physics principles to try to fake authority.
- olivermarks 4y ago
  https://www.freightwaves.com/news/how-many-gallons-of-fuel-does-a-container-ship-carry https://www.freightwaves.com/news/how-many-gallons-of-fuel-d... A low end panamax container ship would require fifty-six million, nine hundred twenty-five thousand KwH of energy (56925 mwh). Academics and beancounters tend to miss out critical factors in how things get done in practice, not in theory. “Farming looks mighty easy when your plow is a pencil and you're a thousand miles from the corn field.” – Dwight D. Eisenhower
  - epistasis 4y ago
    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.
  - shkkmo 4y ago
    You seem to be trying to make a point while ignoring the fact that your point has been explicitly addressed by the article you are attempting to discus (apparently without having read it). FTA: > Past work has suggested that battery electrification of marine vessels is unfavourable given the low energy density of batteries relative to hydrocarbon fuels28,29,30,31. However, their assumptions about battery energy density and cost are outdated, differing in some cases by one to two orders of magnitude from today’s best-available figures of 210 Wh kg−1 specific energy32 and US$100–134 kWh−1 (ref. 33). Furthermore, these studies assumed that the maximum battery capacity is limited by the existing onboard space dedicated to mechanical propulsion systems and fuel storage, so their findings suggest that battery-electric ships would require several recharges to traverse even short routes. > For example, for a 5,000 km range small neo-Panamax ship, we estimate that a 5 GWh battery with lithium iron phosphate (LFP) chemistry, with a specific energy of 260 Wh kg−1 (ref. 34), will weigh 20,000 t and increase the draught by 1 m—a small fraction of the ship’s total height and well within the bounds of the vessel’s Scantling (maximum) draught. For voyages longer than 5,000 km, the increase in draught exceeds the vessel’s Scantling draught. > We find that minimal carrying capacity must be repurposed to house the battery system for most ship size classes and along short to medium-length routes. For a small neo-Panamax containership, representing an average containership in the global fleet, the volume required by the battery system is less than the volume currently dedicated to the ICE and fuel tanks for routes under 3,000 km. For the longest modelled route of 20,000 km for this ship class, the battery would occupy 2,500 twenty-foot equivalent unit (TEU) slots or 32% of the ship’s carrying capacity. Supplementary Table 1 provides the baseline values used for each ship class. > In the baseline scenario, the TCP of a battery-electric ship is lower than that of the incumbent ICE vessel only for ship classes larger than 8,000 TEUs over voyages of less than 1,000 km (refs. 5,40,47,49,50). Over longer voyages, the additional cost of the battery system, increased power requirements and charging infrastructure outweighs the savings from fuel switching and the efficiency gains of direct electrification. However, if the environmental costs of NOx, SO2 and CO2 are considered, the cost-effective range increases to 5,000 km across all size classes given the high emissions rates of HFO relative to the emissions intensity of the US grid.
    - LeChuck 4y ago
      A typical Panamax ship has a DWT of approximately 55000 t (more actually, but this is roughly the max in order to transit the Panama Canal). It's not tenable to sacrifice more than 1/3 of that for batteries. And this for a range of not even 3000 NM!
- _hypx 4y ago
  You should try reading the study. It is clearly a non-economical idea. Physics has nothing to do with it. And BTW, there has been a zero emissions solution to this problem for thousands of years: sail-ships. The fact that we don’t use sail-ships reveals where the problem lie.
  - epistasis 4y ago
    I'm glad you agree that physics has nothing to do with this, but the article spends quite a bit of time evaluating the economics, to the contrary of what you state. That's the entire point of this article. For exmaple: > Under the near-future scenario, the TCP of battery-electric shipping is lower than that of the incumbent ICE ship at ranges around 3,000 km for all ship classes. Science is one of those topics that HN does not do very well. Every time a science subject comes up there are lots of false statements that are very easily contradicts.
    - _hypx 4y ago
      That figure comes from speculation about future technology. Right now, it breaks down at around 1,500 km. And that is based on (from what I can tell) very generous estimates regarding the cost of implementing the idea. I think an honest person will admit that we cannot implement this concept right now. You can only say that maybe in the future it will be possible.
      - epistasis 4y ago
        The title is literally "cost declines raise prospect." This is all that I have claimed. This is all that the article has claimed. Agreed, an honest person can say that. But an an hoenst person can not say that it's impossible because of "physics" or for that matter that it's impossible because of economics! I'm not sure why we should take your assessment that they are "very generous estimates" when you started with the false assertion that it's "very clearly non-economical" while pointing to the paper itself as evidence, when the paper refuted you. If you have a complaint, make it, please don't just smear with innuendo, especially since you are reading the paper. The numbers of $100/kWh, which you talk about as mere speculation, are like forecasting future computing performance and thinking the safe move is to assume no improvement in computing costs. People that have assumed that storage would stay at the same cost have been proven wrong year after year after year. Suggesting that somehow, just now, prices will stop decreasing, is wild speculation with no basis in fact and should be dismissed out of hand, unless the claimant can at least bother to come up with some resin for the change.

epistasis 4y ago

> will be exhausted of power very quickly by the continuous load from underwater propellor propulsion. Sorry, this is your "physics"? Edit: just to be clear but there's an entire paper published in a high profile journal, peer-reviewed, and and the comment is "nuh uh" while appealing to non-existent physics principles to try to fake authority.

olivermarks 4y ago
https://www.freightwaves.com/news/how-many-gallons-of-fuel-does-a-container-ship-carry https://www.freightwaves.com/news/how-many-gallons-of-fuel-d... A low end panamax container ship would require fifty-six million, nine hundred twenty-five thousand KwH of energy (56925 mwh). Academics and beancounters tend to miss out critical factors in how things get done in practice, not in theory. “Farming looks mighty easy when your plow is a pencil and you're a thousand miles from the corn field.” – Dwight D. Eisenhower
- epistasis 4y ago
  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.
- shkkmo 4y ago
  You seem to be trying to make a point while ignoring the fact that your point has been explicitly addressed by the article you are attempting to discus (apparently without having read it). FTA: > Past work has suggested that battery electrification of marine vessels is unfavourable given the low energy density of batteries relative to hydrocarbon fuels28,29,30,31. However, their assumptions about battery energy density and cost are outdated, differing in some cases by one to two orders of magnitude from today’s best-available figures of 210 Wh kg−1 specific energy32 and US$100–134 kWh−1 (ref. 33). Furthermore, these studies assumed that the maximum battery capacity is limited by the existing onboard space dedicated to mechanical propulsion systems and fuel storage, so their findings suggest that battery-electric ships would require several recharges to traverse even short routes. > For example, for a 5,000 km range small neo-Panamax ship, we estimate that a 5 GWh battery with lithium iron phosphate (LFP) chemistry, with a specific energy of 260 Wh kg−1 (ref. 34), will weigh 20,000 t and increase the draught by 1 m—a small fraction of the ship’s total height and well within the bounds of the vessel’s Scantling (maximum) draught. For voyages longer than 5,000 km, the increase in draught exceeds the vessel’s Scantling draught. > We find that minimal carrying capacity must be repurposed to house the battery system for most ship size classes and along short to medium-length routes. For a small neo-Panamax containership, representing an average containership in the global fleet, the volume required by the battery system is less than the volume currently dedicated to the ICE and fuel tanks for routes under 3,000 km. For the longest modelled route of 20,000 km for this ship class, the battery would occupy 2,500 twenty-foot equivalent unit (TEU) slots or 32% of the ship’s carrying capacity. Supplementary Table 1 provides the baseline values used for each ship class. > In the baseline scenario, the TCP of a battery-electric ship is lower than that of the incumbent ICE vessel only for ship classes larger than 8,000 TEUs over voyages of less than 1,000 km (refs. 5,40,47,49,50). Over longer voyages, the additional cost of the battery system, increased power requirements and charging infrastructure outweighs the savings from fuel switching and the efficiency gains of direct electrification. However, if the environmental costs of NOx, SO2 and CO2 are considered, the cost-effective range increases to 5,000 km across all size classes given the high emissions rates of HFO relative to the emissions intensity of the US grid.
  - LeChuck 4y ago
    A typical Panamax ship has a DWT of approximately 55000 t (more actually, but this is roughly the max in order to transit the Panama Canal). It's not tenable to sacrifice more than 1/3 of that for batteries. And this for a range of not even 3000 NM!
_hypx 4y ago
You should try reading the study. It is clearly a non-economical idea. Physics has nothing to do with it. And BTW, there has been a zero emissions solution to this problem for thousands of years: sail-ships. The fact that we don’t use sail-ships reveals where the problem lie.
- epistasis 4y ago
  I'm glad you agree that physics has nothing to do with this, but the article spends quite a bit of time evaluating the economics, to the contrary of what you state. That's the entire point of this article. For exmaple: > Under the near-future scenario, the TCP of battery-electric shipping is lower than that of the incumbent ICE ship at ranges around 3,000 km for all ship classes. Science is one of those topics that HN does not do very well. Every time a science subject comes up there are lots of false statements that are very easily contradicts.
  - _hypx 4y ago
    That figure comes from speculation about future technology. Right now, it breaks down at around 1,500 km. And that is based on (from what I can tell) very generous estimates regarding the cost of implementing the idea. I think an honest person will admit that we cannot implement this concept right now. You can only say that maybe in the future it will be possible.
    - epistasis 4y ago
      The title is literally "cost declines raise prospect." This is all that I have claimed. This is all that the article has claimed. Agreed, an honest person can say that. But an an hoenst person can not say that it's impossible because of "physics" or for that matter that it's impossible because of economics! I'm not sure why we should take your assessment that they are "very generous estimates" when you started with the false assertion that it's "very clearly non-economical" while pointing to the paper itself as evidence, when the paper refuted you. If you have a complaint, make it, please don't just smear with innuendo, especially since you are reading the paper. The numbers of $100/kWh, which you talk about as mere speculation, are like forecasting future computing performance and thinking the safe move is to assume no improvement in computing costs. People that have assumed that storage would stay at the same cost have been proven wrong year after year after year. Suggesting that somehow, just now, prices will stop decreasing, is wild speculation with no basis in fact and should be dismissed out of hand, unless the claimant can at least bother to come up with some resin for the change.