alt Hacker NewsBatteries for ships seems really silly but at the same time its the perfect regime for a ridiculous quantity potentially hazardous items. Nuclear obviously works well here too. You have an unlimited amount of water with which to fight any fires or cool off equipment and you could theoretically engineer a way to dump the entire assembly into the ocean in an emergency.
Hydrodynamics are brutal, but the square-cube law works in your favor. The ocean doesn't care about what's inside your ship. Just the surface of it. The mass is mostly irrelevant. This is why cargo vessels are so large. The bigger the boat the bigger the energy density benefit.
The only real problem is the cost. To compete with a supermax you would need something like two billion dollars worth of batteries to survive a transpacific voyage.
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Nuclear power isn't going to happen for merchant vessels (outside some very limited cases like Russia's state owned icebreakers). Unlike superpower navies, shipping lines can't afford to train and pay nuclear engineers plus the necessary armed security personnel. Many countries refuse to allow commercial nuclear vessels to enter their ports due to fears over terrorist attacks, or environmental catastrophe from an accidental sinking.
It's quite fun to do the math on what it would take to power the largest container ships by batteries. It's not physically impossible but it would displace a good chunk of the usable cargo load.
A single container can contain up to 8mwh of capacity. Just 125 of those gets you to 1gwh. Depending on how quick the ship goes, you might need 1-2 gwh per day. You can conserve energy by going slower. But out of 14K containers, reserving maybe a third for battery could power a ship for quite some time. Enough to e.g. cross the Pacific. There are obvious issues with weight and balance. The volume is doable but the weight creates a lot of issues.
Another challenge is indeed the cost of these batteries. That's about an order of magnitude of where it needs to be to make it financially realistic. But batteries coming down further in cost could make this more feasible. And it's not like these huge container ships are cheap. A couple of tens or even hundreds of millions of dollars worth of battery is reasonable. Billions would be unreasonable.
There are traditionally powered ships carrying many thousands of EVs with batteries already. So, putting a few gwh of battery on a ship is already happening; we're just not using them to move the ship. And batteries made in China are typically shipped to the US and elsewhere for integrating into cars, grid storage, etc. as well. If you can ship it, you might as well use it. And of course battery powered ships are already very popular for lighter short haul like ferries, tug boats, small transport barges on rivers, etc. There are plenty of them operational without major issues. Safety issues seem to be so far not a blocker.
The incentive here is not burning a millions of dollars worth of fuel per journey. Container ships use a lot of fuel. That adds up fairly rapidly to offsetting the cost of the battery. I think the question is not if batteries will be used on ships but how much batteries typical ships will have.
More modern battery chemistries are less hazardous as well. LFP for example is both cheaper and more stable, just at the cost of energy density. Which might be fine if you have a giant ship that can handle a large volume and mass of batteries to save on fuel costs.
Do note that you could go for technology like the 100 hour ("0.01C") iron-air batteries "form energy" works on, especially if you're willing to swap them in port instead of DC fast charging through a temporary high voltage link.
You'd get the benefit of charging them when it's sufficiently convenient (off-peak), and the lower energy density and very low power density don't matter nearly as much on a ship.
I hear you and while this is out of scope for the article a lot of sailing yachts are being converted to electric motors.
What kind of shore-to-ship power connection would you need to recharge the batteries while the ship is unloaded/loaded?
> You have an unlimited amount of water with which to fight any fires
Fire on a ship is extremely dangerous. Think about what your training and your first instincts both tell you to do if there's a serious fire. Where I am the training starts with four words: "Get out. Stay out". But you can't just leave a ship, in the ocean you will drown. Even lifeboats, if they're available and can be used, are much more dangerous than we'd like.