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> Lithium-ion batteries are very compact, but they cannot be considered sustainable and bring safety risks C'mon this is silly. The dominant safety risk of a s
by samatman 5y ago
> Lithium-ion batteries are very compact, but they cannot be considered sustainable and bring safety risks
C'mon this is silly. The dominant safety risk of a small vessel (and all of these are small in modern terms) is capsizing in heavy weather, with the loss of all hands.
LiFePO batteries, built into a bank with really excellent waterproofing, would be quite adequate to the job. If lithium battery technology in general proves to be unsustainable, we may as well pack up and go home, because decarbonization isn't going to happen.
Taking the average specific energy of LiFePO from Wikipedia, we get 12.5kg per kWh, almost five times denser for a proven technology you can buy off the shelf. 4.4 tonnes for the larger battery, compared to 9 tonnes for the smaller saltwater battery sketched out in the draft, and 21 tonnes for the larger one. That's 16.6 tonnes of additional life support the ship can carry; stowing a ship is a classic knapsack problem, there's no such thing as an "acceptable" amount of tonnage and volume to leave out of the equation.
Using saltwater batteries here would be an ostentatious stunt. Arguably that's what this whole thing is: an ostentatious stunt. But it doesn't have to be, it's a good proving ground for much larger sail ships, and a thousand tonnes here, a thousand tonnes there, pretty soon you're talking about real cargo. Electricity requirements should be very much sublinear with cargo capacity as well.
- lardo 5y agoI've never sailed in blue water, but I thought that modern weather and navigation infrastructure mean bad weather can be largely avoided. Either way fire on board is still something to be avoided.
- jgeada 5y agoMajor storms can move faster than most sailboats can sail out of the way.
- samatman 5y agoThe electricity still must be distributed around the ship. Proper weatherproofing can easily make the battery the least likely point of failure in the whole system.
- nradov 5y agoSure modern motorized merchant vessels generally route around major named storms (except for rare tragedies like the SS El Faro). But if you want to carry cargo reliably for paying customers then you're going to have to sail into bad weather occasionally. Winter weather in the North Atlantic is usually bad and can change quickly. There's no avoiding it.
- decafninja 5y agoNot a sailor nor a maritime expert by any means, but IIRC Japan now has submarines that uses lithium-ion batteries to power submerged movement. Granted it is mil-spec.
- Someone 5y agoYep. https://www.popularmechanics.com/military/navy-ships/a34428531/japan-new-submarine-lithium-ion-batteries/ https://www.popularmechanics.com/military/navy-ships/a344285...
- rocqua 5y agoI think for ships of this size, fire is a bigger risk than capsizing.
- outworlder 5y ago> If lithium battery technology in general proves to be unsustainable, we may as well pack up and go home, because decarbonization isn't going to happen. Exactly. Lithium is not that uncommon. It's just that the reserves that we have found (so far) where nature helpfully decided to concentrate it for us are not very common. If we don't use those, then it's expensive to extract (both in money and energy). That's another argument for expanding renewables. Put them to work to extract lithium from salt water. Oil had a very similar argument, but we keep finding reserves and devising ways to use previously uneconomical reserves. Now, once extracted, we recover most of it when it comes time for recycling. I bet older marine batteries would have plenty of uses as second-life energy storage for stationary applications. It may take decades until we even have to recycle them. > safety risks As for the safety risks... One of the main ways to contain a battery fire is to spray water on it. Is ocean water is too salty(therefore, conductive) for this application?
- noir_lord 5y agoWonder if you could design the battery to be ejectable - you'd want some way to get them in and out anyway. In the event of a fire just dump it overboard. I guess the usual problems apply, you can't eject underwater without a pressurised system (now we have a torpedo launcher) and you can't eject over the waterline because you want the battery low for center of mass/center of bouyancy. Kinda funny image though "Launch Ze Batteries!"
- _ph_ 5y agoMost yachts are switching to LiFePO, because they perform so much better than any lead-based batteries. Haven't heard about safety issues.
- Teknoman117 5y agoI still remember someone demonstrating the relative safety of LiFePOs by driving a nail straight through one in front of me. The LiPo immediately started smoking and within a few seconds erupted into flame, the LiFePo (an A123 cell) didn't really do much of anything at all, other than no longer functioning.
- andromeduck 5y ago> If lithium battery technology in general proves to be unsustainable, we may as well pack up and go home, because decarbonization isn't going to happen. Nuclear + Hydrogen would still be available.