| ▲ | colechristensen 5 days ago |
| The recharging infrastructure for such a vessel would be an interesting challenge. Likewise if those batteries caught fire. |
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| ▲ | manquer 5 days ago | parent | next [-] |
| No need do charge in-situ, the ships (and ports) already transfer several times the battery volume and weight on berthing quickly . The battery systems could be designed to leverage that . Fire hazards are there for any fuel, Safety systems evolve to handle them. The environmental impact would be more localized than an oil spill. |
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| ▲ | mbirth 5 days ago | parent | prev | next [-] |
| Just make the battery banks container sized and swap them out with fresh ones while doing the main cargo. Then service and charge the old ones. |
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| ▲ | pbmonster 3 days ago | parent | next [-] | | That also means you can trivially optimize your fuel/cargo ratios. Going across the pacific? Just load 200 more battery containers. Singapore to China right after? Room for 400 FEUs more than normal. | |
| ▲ | amluto 3 days ago | parent | prev [-] | | It’s not quite “just”. A way to safely and efficiently connect and disconnect them would be needed. |
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| ▲ | rgmerk 5 days ago | parent | prev | next [-] |
| A quick googling suggests that unloading such a vessel takes at least a couple of days, more likely 3-4. Assuming two days available to charge the vessel, you'd need about 100MW continuous. Not trivial, but doable. As far as battery fires go, sure, but a) there are already a lot of electric ferries in service so designing safe maritime battery packs isn't a new challenge and b) the alternative isn't exactly risk free either; we've seen plenty of oil spills from ships. |
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| ▲ | lostlogin 5 days ago | parent | next [-] | | The fire thing comes up with cars all the time. Petrol cars are vastly more likely to catch fire, but are a bit easier to extinguish. I can only imaging how hard it is to put out a ship fire, but is there any reason to see that the situation would be different? Bunker fuel appears to be less flammable. | | |
| ▲ | wakawaka28 3 days ago | parent | next [-] | | >Petrol cars are vastly more likely to catch fire, but are a bit easier to extinguish. Petrol cars at most marginally more likely to catch fire, if at all. They cannot catch fire by simply being submerged in a foot of water, like an EV can. They are far easier to extinguish than EVs, which are practically unextinguishable and can reignite weeks or months later. You can use a fire extinguisher on a petrol car fire if you catch it early (they are usually electrical fires). If you catch an EV fire early, your best course of action is to run away as fast as possible. Ships are not known to be subject to fires because the types of fuel they use are not generally so volatile, and they are literally surrounded by water which can be pumped to the deck or wherever to drown any fire. Some use diesel, which is difficult to light even with a match. Others use heavy crude oil that looks like tar and would be similarly difficult to ignite accidentally. A battery fire on a ship would be a HUGE problem, as we have seen with ships carrying EVs. I think another often-overlooked risk of EVs is the arson risk. Even if batteries are less likely to catch fire (in the first few years of use, if you baby them), a bad actor can start an unextinguishable fire by shorting out or otherwise igniting a battery pack. This is easy to do and devastating. | | |
| ▲ | lostlogin 3 days ago | parent | next [-] | | > Petrol cars at most marginally more likely to catch fire, if at all. “An American insurer found that just 25 out of 100,000 EVs suffer fire damage. By comparison, 1530 per 100,000 ICE cars experience fire, and hybrid vehicles suffer a much higher risk of 3475 per 100,000 .” https://www.autocar.co.uk/car-news/electric-cars/how-much-fi... | | |
| ▲ | wakawaka28 3 days ago | parent [-] | | I don't believe those numbers, and even if I did it is a fact that EV fires are far more dangerous than petrol fires. As for hybrid vehicles, you get the best and worst of both worlds including two separate high-energy systems that can catch fire. The average age of an EV is way lower than the average age of a petrol car, and they also tend to be toys for the wealthy who do not abuse them as much as the owners of petrol vehicles abuse theirs. EVs are often ruined by minor accidents or water ingress, and can pose a major fire/explosion risk at any shop that would dare to undertake a repair. Just the other day I heard one EV owner was quoted $12k to repair an issue caused by spilling a bottle of drinking water inside the EV. As I said, the fact that these fires can't be extinguished is a major arson risk, as is their toxicity. Insurers will eventually have to raise their rates to cover the extreme risk posed by EVs. https://www.himarley.com/news/ev-charging-fires-are-rare-but... Storing damaged EVs safely means you need to spread them out like a hundred feet apart or something, so that one of them igniting doesn't start a whole lot of EVs on fire with toxic and inextinguishable flames. There are no solutions to these problems after having EVs on the market for several years, because it's a very hard problem to solve. |
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| ▲ | LtdJorge 3 days ago | parent | prev [-] | | And you get downvoted, lol… | | |
| ▲ | wakawaka28 3 days ago | parent [-] | | Yes lol. I should have a thousand points by now probably, but every time I get on a streak of telling people uncomfortable truths they knock me down like 50 points. |
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| ▲ | cellular 3 days ago | parent | prev [-] | | Just hang the batteries over the water in containers. Dip them into water if they catch fire. | | |
| ▲ | darth_avocado 3 days ago | parent | next [-] | | Electric battery fire is not exactly extinguished with water. | | |
| ▲ | Maakuth 3 days ago | parent | next [-] | | This is largely a misconception that's caused by the fact that EV fires are hard to extinguish with normal water sprays. That is because the bettery packs are designed to be water proof, so it is hard to get the fire patrol's water in. If you can immerse the pack in water, the fire is extinguished without much trouble. That's unlike petroleum fires, where the fuel is lighter than water and liquid, so water spray will boil and spread the fire instead of extinguishing it. | |
| ▲ | Qwertious 3 days ago | parent | prev [-] | | It doesn't need to be extinguished, it just needs to be removed from the ship. Even a second of airtime (and a healthy lateral velocity) might be enough that the ship is out of the explosive radius of the battery. |
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| ▲ | PunchyHamster 3 days ago | parent | prev [-] | | sure, and what you do with remaining 499 burning containers when your crane is dipping the first one ? |
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| ▲ | halJordan 4 days ago | parent | prev [-] | | How many ships in port charging at a time? Honestly sounds like a good place to stay a few of those micro reactors lockmart claims to have | | |
| ▲ | rgmerk 4 days ago | parent | next [-] | | The Port of Los Angeles is one of the largest ports in the USA, and has about 1,800 ship arrivals annually. If they were all electric, all of this size, and required a full charge on arrival, you’re talking about (very roughly) 1 GW continuous power requirement for charging the ships. That’s a lot; no bones about it, but it’s not unprecedented - aluminium smelters and data centers are similarly hungry for power. | |
| ▲ | anticodon 3 days ago | parent | prev | next [-] | | Wouldn't it be much easier than to put micro reactors on a ship directly? Like on Russian icebreakers that can function on one load of fuel for 3 or 5 years, don't remember exactly but at least 3 years for sure. | | |
| ▲ | rswail 3 days ago | parent [-] | | Containers in general as well as palletization dramatically improved the economics and port efficiency around the world. Using containerized energy that can be offloaded and charged and swapped at ports is much more efficient way to spread the cost and infrastructure and safety around the world. There are many ports where you really don't want any form of radiation/nuclear materials available. |
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| ▲ | baq 3 days ago | parent | prev [-] | | If you have one ship to charge, maybe. Ten is in the standard nuclear power plant territory which is politically impossible to build outside of China. | | |
| ▲ | rgmerk 3 days ago | parent | next [-] | | You’re not going to build a nuclear reactor (other than military ones) anywhere near a major port. You power this the same way you power aluminum smelters - you have a big honking grid connection and build the generation capacity in places with more room. | |
| ▲ | speedgoose 3 days ago | parent | prev [-] | | France plans to build 6 more reactors in existing power plants. |
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| ▲ | toomuchtodo 5 days ago | parent | prev [-] |
| Sodium batteries have substantially reduced thermal runaway risk compared to lithium. Worst case, the ship sinks during a fire and the batteries are flooded. Charging infra is likely similar to existing EV ferry charging infra. Ship pulls into the berth and starts soaking the battery storage up to 1C up until departure. Could probably use a heat exchange and raw water available for battery cooling to maximize charge current curve, actively cooling the battery storage during charging. https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/2023-04/... https://old.reddit.com/r/electricvehicles/comments/1m8wlou/e... |
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| ▲ | aeonfox 5 days ago | parent [-] | | Na-ion cells have roughly half the volumetric and gravimetric energy density of NMC, so it's double the weight and double the space. Apart from still being at least as—if not more—expensive as LFP, they also have a sloping voltage curve, vs lithium with is relatively flat, which poses problems for voltage conversion, and these engines are going to be taking kilovolts of power. So I think those problems would need to be solved first. | | |
| ▲ | amluto 3 days ago | parent [-] | | Is the sloping voltage curve that much of a problem? ISTM it might simplify cell balancing and SOC determination. | | |
| ▲ | aeonfox 3 days ago | parent [-] | | I'd imagine it makes providing constant AC voltage to the engines pretty tough. It's even a problem for home energy storage because you need an inverter that can handle a very wide range of input voltages. Most inverters will cut off well before the Na-ion battery is full drained, vs a lithium which can go pretty much all the way to 0%. | | |
| ▲ | amluto 2 days ago | parent [-] | | I don’t know much about the kind of giant motor that would be used in a ship, but as a general principle: the load that a motor presents to the drive electronics does not resemble your house in the slightest. To power your house (or, more generally, supply vaguely sine-wave like output at a constant voltage), you need a converter that will convert DC at the battery voltage to AC at the desired voltage. If a buck converter is used, for example, the AC voltage can only ever be lower than the battery voltage. If you use a cheap square wave inverter, it’s possible that the output and input voltages must actually be equal. A motor, though, is a highly inductive load, and large motors will and do operate from truly gnarly supply waveforms as long as the current waveform is approximately correct. Industrial VFDs (variable frequency drives) do unspeakable things involving switching a DC bus voltage across the motor via H bridges at tens of MHz, which is a horrible thing to do the the wiring between the drive and the motor if it’s not extremely short. (There are, recently, some guidelines that specific types of wire with twisted conductors, better than average insulation, and high quality shields should be used to improve tolerance of the fact that rather impressive standing waves can appear in the wiring if the wiring is a quarter wavelength or longer.). I can easily imagine designing a VFD that works just fine over a respectable range of DC input voltages by adjusting its duty cycle accordingly. One way to think of this is that a VFD looks kind of like a buck converter where the inductor is free in the sense that it’s already right there in the motor. If it’s designed right, it will handle the battery’s full voltage range, and the inductor will still be free :) | | |
| ▲ | aeonfox 18 hours ago | parent [-] | | > I can easily imagine designing a VFD that works just fine over a respectable range of DC input voltages by adjusting its duty cycle accordingly. [...] I can easily imagine designing a VFD that works just fine over a respectable range of DC input voltages by adjusting its duty cycle accordingly. I imagine it's not the waveform or current that matters so much, as the voltage. These motors would be powering massive blades encountering incredible resistance, so you need megavolts to move them, with an input voltage all the way down to near zero. > H bridges at tens of MHz Imagine the MOSFETs on this thing! Do they have something that scales up to MV? That sounds like an engineering challenge in itself. Full disclaimer: electronics is not my wheelhouse, though I have played around with motor controllers. | | |
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