Ships tend to go not change course nearly as much on a several day journey. I guess a propellor could run in reverse for regenerative breaking, but it wouldn’t help much.
Also wave based generators that could also act as dampers/suspension and they wouldn’t steal energy from forward motion like wind would (depending on if you’re generating wind energy or using wind to buttress the batteries).
Ideally a combination of sails coupled with batteries and wave generators sounds like it would be very energy efficient.
There are some vessels that have single use emergency brakes, but the latest trend is to have motor 'pods' that are electrical and that can be used both for normal propulsion as well as to perform emergency stops that are quite impressive given the size of the vessels they are on. Typically an oceangoing vessel requires at least 3, but commonly 5 to 10 ship lengths to come to a full stop from moving forward under power. This is not necessarily because of limitations of the propulsion unit, but simply because stopping that much tonnage too fast would do as much damage as a collision would. With classical engines there is far more rotating mass so it would take much longer than with electrical propulsion to react before the beginning of the braking phase.
Unless you have a large sail to generate thrust to spin the propeller...
Ocean going container vessels on the other hand use massive direct drive two stroke diesel engines (usually they only have a single engine). They have no gearbox. The only way to go-astern is to literally start the engine in reverse. This can only be done up to a limited speed, otherwise the windmilling effect of the water passing through the prop would overpower the starting air.
Suffice to say, I'd put a long bet on the overwhelming majority of containerships being powered by internal combustion engines in 30 years time. If we get our act together we might have come up with an alternative / synthetic fuel by then but I wouldn't hold my breath.
https://en.wikipedia.org/wiki/MV_Ampere
They are quite impressive but they are still very far away from your average ocean going cargo vessel.
Near me, we now have a hybrid ferry, no charging infrastructure, but it still uses much less fuel than before it was refit, so that's cool too. It's bigger than the one you linked and sails on a longer route: 2,499 passengers, 202 vehicles, typically serves an 8.6 mile route.
Allseas is putting the reactors on their vessels as well iirc.
* a 5,000 km electric range. * 40MW continuous power requirement for a 21.5 knot cruise speed[1] for a 14000 teu container vessel: * the size and weight capacity for the batteries being the same as the fuel capacity for a 14000 teu container vessel (taking the upper figure from [2]) * the battery pack having similar gravimetric (weight) and volumetric(size) energy density as this battery pack in a modern Chinese NMC EV pack[3]
The short version is that the battery vessel would require about 25,000 tonnes of batteries for a 5,000km range under those assumptions, which compares to the current fuel capacity of approximately 13,000 tonnes. Volumetrically, it's even closer - about 17,000 cubic metres, compared to about 13,000 for the bunker fuel.
Furthermore, it's worth considering just how much cargo the ship carries. One teu corresponds to about 33 cubic metres of cargo space (not counting the space taken up by the walls of the container), so the ship can carry about 462,000 cubic metres of cargo. So the additional space required to carry an additional 3,500-odd cubic metres of batteries corresponds to only about 0.8% of the ship's total cargo-carrying capacity.
I was surprised at just how doable this is, to be honest. What threw me is just how much bunker fuel ships can carry; if I'm doing the sums right, a ship like this can carry enough fuel to circumnavigate the globe a couple of times over. It may well make economic sense but it's not really necessary to have that kind of range to operate the ship safely.
[1]https://www.man-es.com/docs/default-source/marine/tools/prop... [2]https://www.freightwaves.com/news/how-many-gallons-of-fuel-d... [3]https://www.batterydesign.net/zeekr-140kwh-catl-qilin/
eimrine•2h ago
themanmaran•1h ago
- 20k square meters of hull space
- If fully covered with solar panels, on a sunny day, you could expect 1-2 MWh (when averaging in night time)
- Current diesel engines typically output 60MWh continuously while underway.
And that's not factoring in the solar panels getting covered in salt over time and losing efficiency. Plus preventing the ship from actually loading / unloading cargo efficiently.
It's not just a matter of panel efficiency either. If we had magic panels that could absorb 100% of the suns power over the 20k sqm deck, it would only equate to about four times as much (8% of the overall power need).
tshaddox•44m ago
probablypower•39m ago
SigmundA•19m ago
SigmundA•25m ago
60 MWh per what? Per hour? thats just 60 MW continuous POWER or 1440 MWh ENERGY per day.
rgmerk•1h ago
I’m too lazy to do it myself but 5 minutes of searching and calculating will show you that the area of solar panels required to move a ship is far, far, larger than the area of that ship.
Not to mention that a container ship’s deck is typically completely covered with, well, containers.
Also, lithium isn’t scarce.
Onavo•1h ago
Honestly DJI and Boeing should get into this business. A boat's sail basically a plane's wing, aerodynamically speaking. They share a lot of similarities with endurance gliders.
bluGill•46m ago
throw-qqqqq•30m ago
Try to approximate the area needed to generate e.g. 50MW propulsion. It would be measured in hectares.
epistasis•1h ago
There's more than enough lithium out there, more discovered every month, and the perception that we are limited by lithium is mostly out there because certain media sources are trying to help out there fossil fuel friends by delaying the energy interchange by a few years.
Whether battery ocean shipping containers make technical sense is a different question, but I wouldn't worry about lithium use!
jiggawatts•46m ago
Lithium, rare earth metals, and a bunch of others are only "scarce" because right now China is the only country willing to put up with the pollution levels that the cheap, dirty version of their extraction produces.
Everything can be produced cleanly, safely, etc... but that comes at a price.
It's like when employers complain that "nobody wants to work". That needs to be translated to "nobody wants to work for the low wages I'm willing to pay".
givemeethekeys•1h ago
I wouldn't underestimate what creative and dedicated engineers can accomplish.