Batteries 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.
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.
> 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.
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.
for sailing yachts that makes sense. They would use wind for most movement. While in harbor though they want the finer control that being under power allows - they don't need high speed/high power then though. They also don't spend a lot of time in this situation.
They're more like sail assisted than really "sailing" as such. Worth doing in some cases but saves maybe 10% of fuel under optimal wind conditions. The most suitable vessels will tend to be bulkers, car carriers, and tankers. Container ships are actually the hardest to add sails because they interfere with the stacks and the port cranes.
It makes so much sense. The one's I've seen can be engaged in recovery mode while running your sails, so you can spin the prop and generate electricity. They only get a few hours run time fully charged, but that's plenty for port maneuvers or trip to pick up your crab pots.
I assumed they would use sea water for cooling but that doesn't seem to be the case? Maybe the battery coolant is cooled using some sort of sea water heat exchanger?
You really don't want to cool anything with sea water directly. It's corrosive due to the salt and contains all kinds of fun things from flotsam to critters, some of which might make a home in your cooling loop. in this case, additionally, sea water is conductive and that's not acceptable in a battery.
However, feeding the coolant through some sort of heat exchange with the sea water is very likely something they do.
Yes, that's the absolute norm (you often also want to cool the exhaust pipe itself and there you often see coolant water pumped straight into the exhaust). That's the obvious thing to do: You do have a huge reservoir of readily available coolant, tapping it is the sensible thing to do :) That's why I fully expect them to run their coolant through some heat exchange with sea water.
Fossil fuel engines are significantly less efficient than electric ones... so need a lot more cooling. I'm sure getting rid of the need for that would be a nice win that might be practical with electric engines.
Batteries and electric motors are fussy about temperature, you still need thermal management. Probably not as large a system, but you might need a heater or sub ambient capability.
Also saltwater is conductive so if you submerged your batteries in it, you'd have an immediate short circuit. It's definitely through a heat exchanger.
Question is can they get enough power to be useful. Marine diesel engines are very fuel efficient, fuel oil is very energy dense, and they need to run for a long time. Electric cars work in part because people expect to refuel few couple hours anyway. Enough batteries to cross the ocean is going to be vastly worse.
The only useful picture in the article is a "solar powered board", which doesn't give a good scale but appears to be barely enough solar power for the rich owner to enjoy their luxuries and will barely move all day while forced to anchor all day. I'm sure it can go really fast on battery power, but not for long. Sails would be a better primary movement source with battery for in harbor navigation or when the wind stops backup only.
> Question is can they get enough power to be useful. Marine diesel engines are very fuel efficient, fuel oil is very energy dense, and they need to run for a long time.
Washington State Ferries refit one of their largest ferries (190-car capacity) as a hybrid recently. They replaced two diesel engines with batteries, leaving the other two engines in place. This provides for significant fuel savings. When shore charging is implemented, fuel use will be reduced even more.
I imagine there are also uses where batteries fully replace engines. I've got a tiny boat for casual fishing, you tend not to use the engine that much, and electric propulsion is likely quieter and can probably modulate to slower speeds which could replace a separate electric trolling motor.
A lot of ships don't go across oceans and can benefit from batteries. Think ferries, feeder ships, river transport. Those all dock in relatively predictable intervals.
As a crazy thought: On predictable routes in shallow enough water, implement an underwater power source similar in function (if not physically similar) to overhead electric bus/trolley power lines? The boats would move along their routes with a cable running down to to a connector that slides along the power source.
I'm imagining channels in a busy waterway or a regular ferry route. Of course it needs economy of scale, but at that point everyone saves on batteries, etc. Unless there are submarines, I don't know what would pass under the boat and cut the connection.
Maybe watercraft usage or routes aren't predictable enough? Maybe the sliding connector is too expensive underwater, especially in sea water.
Interesting. Generally, waterborne freight is far cheaper than rail. Also, at least sometimes you might need to transfer between modes - ship to rail then rail to ship. But with the underwater catenary solution now we're talking about new infrastructure (not to mention R&D, etc.).
As a sort of transitive analysis: Standard waterborne energy costs are included in the superior pricing of waterborne freight compared to rail. If the underwater catenary solution is competitive to standard waterborne energy costs, it beats rail easily. If the underwater catenary is not competitive, it has no value anyway.
It could still have value if we price in, as we should, the externality of GHG output. THe underwater catenary could reduce GHG output in busy waterways by powering boats that don't have batteries.
The maintenance of these power points would be astronomical, even if the basic theory could work, which I'm not 100% sure of. You'd have a single high-voltage cable, a pickup pantograph that wraps around the cable acting like a transformer that wheels along the cable, and AC current in the cable with the water itself being the ground reference. I can't imagine any other way it could work.
I had always imagined a system of autonomous submarines that function as tugboats along popular routes and then container ships would just function as barges that are hauled by these autonomous submarines. These submarines recharge their batteries automatically by docking to underwater charging stations.
sea water is too corrosive and too conductive. You could make a single overhead cable and use sea water as your return work. However it wouldn't be practical since ships multiple stories tall need to pass under the wire (and draw a lot of power), while also tiny fishing boards that couldn't even get a pole that high.
The same problem with height would also be an issue for the underwater thing. Quick googling suggests a very large container ship might have a draft of 16-17m when fully loaded. Probably you want the catenary at 20m depth then. How does a small get their pantograph (or whatever you'd call it) down to that depth, and then move forwards without the pantograph sticking 20m down creating a huge amount of drag. Not to mention how do you make the connection between the pantograph and the catenary in the (conductive) sea water?
> Probably you want the catenary at 20m depth then. How does a small get their pantograph (or whatever you'd call it) down to that depth,
Does the connection from the 'pantograph' to the boat need to be rigid? Use a cable? Maybe it's not for the smaller boats which can't handle a 20m (probably more like 40m for the angle and slack) cable, but also need less power and thus pollute less.
> and then move forwards without the pantograph sticking 20m down creating a huge amount of drag
Presumably, the catenary's route would be cleared of obstructions - maybe even on a frame elevated over the floor, maybe at relatively constant depth - or do I misunderstand? Would a 40m cable cause that much drag? Obviously the pantograph would have to be low friction and highly reliable.
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.
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.
A step before that is to have shore power to run things when in port.
In general stopping pollution near populated areas and busy ports is a bigger win and so a good place to start.
However, feeding the coolant through some sort of heat exchange with the sea water is very likely something they do.
Aren't ship engines usually cooled with sea water already (through a heat exchanger, not directly)? So it's not really something new
The only useful picture in the article is a "solar powered board", which doesn't give a good scale but appears to be barely enough solar power for the rich owner to enjoy their luxuries and will barely move all day while forced to anchor all day. I'm sure it can go really fast on battery power, but not for long. Sails would be a better primary movement source with battery for in harbor navigation or when the wind stops backup only.
Washington State Ferries refit one of their largest ferries (190-car capacity) as a hybrid recently. They replaced two diesel engines with batteries, leaving the other two engines in place. This provides for significant fuel savings. When shore charging is implemented, fuel use will be reduced even more.
I imagine there are also uses where batteries fully replace engines. I've got a tiny boat for casual fishing, you tend not to use the engine that much, and electric propulsion is likely quieter and can probably modulate to slower speeds which could replace a separate electric trolling motor.
I'm imagining channels in a busy waterway or a regular ferry route. Of course it needs economy of scale, but at that point everyone saves on batteries, etc. Unless there are submarines, I don't know what would pass under the boat and cut the connection.
Maybe watercraft usage or routes aren't predictable enough? Maybe the sliding connector is too expensive underwater, especially in sea water.
As a sort of transitive analysis: Standard waterborne energy costs are included in the superior pricing of waterborne freight compared to rail. If the underwater catenary solution is competitive to standard waterborne energy costs, it beats rail easily. If the underwater catenary is not competitive, it has no value anyway.
It could still have value if we price in, as we should, the externality of GHG output. THe underwater catenary could reduce GHG output in busy waterways by powering boats that don't have batteries.
Example (7 minute charge time):
https://global.abb/group/en/technology/did-you-know/maid-of-...
> Probably you want the catenary at 20m depth then. How does a small get their pantograph (or whatever you'd call it) down to that depth,
Does the connection from the 'pantograph' to the boat need to be rigid? Use a cable? Maybe it's not for the smaller boats which can't handle a 20m (probably more like 40m for the angle and slack) cable, but also need less power and thus pollute less.
> and then move forwards without the pantograph sticking 20m down creating a huge amount of drag
Presumably, the catenary's route would be cleared of obstructions - maybe even on a frame elevated over the floor, maybe at relatively constant depth - or do I misunderstand? Would a 40m cable cause that much drag? Obviously the pantograph would have to be low friction and highly reliable.