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"Currently named "Battery Tanker X," the prototype won't be going very far. Pushing a vessel through draggy water is a nightmare for battery-powered electric propulsion systems, so the ship's maximum range before it burns through too much battery to make the trip economically feasible is slated at just 300 km (186 miles).

A full production "Power Ark" the same size, says PowerX, might move about 4,190 GWh of electricity annually from renewable sources in Hokkaido to meet demand in Aomori just 100 km (62 miles) away, making use of transmission infrastructure already in place but soon to be abandoned as fossil fuel-based generation capacity is gradually shut down. "

I'm reading a lot of comments seemingly missing these details. Interesting and seems to be useful in Japan's geography that I'm not personally used to thinking about.

What detail of Japan's geography that's supposed to make this viable did you pick up from that text?

Aomori is not some island so remote and isolated they can't possibly run underwater cables to. It's on Honshu. You know, the main island. On the same power grid as Tokio.

"making use of transmission infrastructure already in place but soon to be abandoned as fossil fuel-based generation capacity is gradually shut down. "

From article:

"Why not just put down an underwater cable? That's a fine question. PowerX points out that Japan is surrounded by deep seas, and prone to earthquakes, and says in a press release that "the ship-based solution resolves issues such as long downtime from undersea cable malfunctions and repairs, as well as the high costs associated with ultra-high voltage connections and substations.""

Using all of its internal battery for propulsion I wonder how far it could go.
I guess every ship is shipping electrons right? I don't think you can call storing chemical potential energy 'electrons'.

This is an interesting concept - I guess if electric cars make sense then this also makes sense for transporting energy?

> I guess if electric cars make sense then this also makes sense for transporting energy?

I don't see how that follows. The point of a electric car isn't to transport the electricity, it's to transport matter. There's no shortcut here: the only realistic way (short of Star Trek transporter beams) we can get the cargo from point A to point B is by physically moving it.

In contrast, we already have other ways to transport energy which work quite well. It's hard to see how this absurd concept could possibly be competitive with them.

I'm sure there are edge cases where putting batteries in ships can make sense. Let's assume the following is true:

1) Two islands exist relatively close to each other. 2) Both have enough wind power to meet demand on windy days. 3) Deep waters, strong tidal currents, tsunami risk or some combination make power lines between the islands somewhat expensive or unreliable. 4) Battery storage is required to meet demand on days with little wind. 5) Storing these batteries on ships is not significantly more expensive than storing the batteries on land. (Maybe real estate prices are high, regulations are stricter on land, etc.)

In such a case, it may be more economical to move the ship holding the batteries than to set up cables intended just for low wind periods. And if there are many islands involved, an ecosystem of ships may scale better than cables, for instance if demand is seasonal or varies for other reasons.

Basically, these are similar reasons to why LNG regasification ships exist, instead of just building fixed land-based facilites where needed.

You can put matter on grid powered trains instead of battery powered self propelled vehicles.
Tangentially, the book The Vital Question is fascinating: it explains how life on earth is basically just proton-moving machines with flair (and how such machines could have come to evolve in the first place).
Every living thing is just trying to tap into the great waterfall of entropy to spin their wheel for the little time they can.
I think most people just don’t realize that when you charge a battery you’re not literally just filling it up with electrons.
My guess would be that pretty much everybody knows that this mental model is wrong, which is why the author considered it appropriate to jokingly play naive, because just calling it "bizarre" felt too weak.
On your first point, ‘electrons’ is an example of synecdoche: https://en.m.wikipedia.org/wiki/Synecdoche
Electric cars don't transport energy, they transport people.
241 megawatt hours isn't very much...

A medium sized power station is say 300 megawatts.

So if you want to transport this power just a few tens of miles, you probably need a fleet of 10+ ships constantly charging and discharging.

I am very dubious that that works out cheaper than just laying a cable, even through deep water.

It's in the article:

"Why not just put down an underwater cable? That's a fine question. PowerX points out that Japan is surrounded by deep seas, and prone to earthquakes, and says in a press release that "the ship-based solution resolves issues such as long downtime from undersea cable malfunctions and repairs, as well as the high costs associated with ultra-high voltage connections and substations."

I'd absolutely love to do DD on this project. It has all kinds of interesting bits to research. On the assumption that they have done their homework there must be something non-obvious that they know that outsiders don't.
If we cared about shipping energy, we'd just use our Nuclear-powered ships.
I mean it’s a press release. Those don’t cost anything.

The only application of this that seems half feasible is maybe some kind of post-disaster recovery where for whatever reason you’ve ruled out using a generator.

Even then you'd probably be better off shipping a mixed load of diesel trucks and large generators.

Even the larger version doesn't make a whole lot of sense, you'd be looking at keeping the ship in port for quite a while unless those batteries are going to be charging and discharging at very high rates but that would shorten their life (and hence the number of trips). They are aiming to do 'short runs' only (100 km is mentioned in the article but the economic range is a bit larger) which makes it even more dicey economically.

Their transportation costs per KWh as quoted in the article exceed current generation costs by a factor of three already. 214 MWh is a proverbial drop in the bucket on grid scale and even 10x isn't all that much, and you can only deliver power if you have enough of those vessels to guarantee overlap at the destination or you're going to have to deal with outages.

I wonder who is investing in this project.

Whether or not this is a sound engineering decision, it also sounds a bit like a hack in Factorio that makes sense due to a quirk in game mechanics.
There’s the cargo ship mod and chargeable batteries and accumulators that you can ship - maybe that’s how they validated the idea in the first place…
Dyson Sphere Project has Accumulaters (batteries) you can fill on an energy rich planet and ship to another which is energy poor.
Can anyone run the math on how many megawatt hours a full oil tanker might be for comparison?

https://transportgeography.org/contents/chapter4/transportat...

Is the ratio something like this? 41 to 0.5? 82x?

Sources say 13.7 MWh of energy per ton of LNG. This is in BTUs so at 60% efficiency of a fairly modern gas plant would yield 8.2MWh of electricity generation potential per ton. The largest LNG carrier carries over 80,000 tons of LNG https://en.m.wikipedia.org/wiki/LNG_carrier

So that would work out to 656 GWh of electric generation potential for a full load of the largest LNG carrier. More than 2000x the capacity of the battery carrier.

Oil is much more energy dense.

Using current gen batteries, this is a cargo of about 1200t for 240MWh

Oil would be 13000MWh of chemical energy. Or a replacement for 2000-7000MWh of electricity.

It would never be worth transporting electricity from the oil well, but if the option is transporting oil 3000km or transporting electricity from a wind turbine 200km away, the battery-ship is a better use of the ship (but maybe not a better use of the batteries than using a wire).

It would be far better to use the energy locally to disassociate sea water and turn it into hydrogen, then ship the hydrogen.

They're doing this with the sea change ferry in San Francisco. The hydrogen that it runs on will be created from electricity and seawater at the point if use, on a floating fuel barge. It gets even better, they're using fully green hydroelectric energy from Hetch Hetchy reservoir, so the whole chain is about as green as possible, and is really an example for the rest of the world to follow.

https://www.sfchronicle.com/climate/article/san-francisco-fi...

The much higher capacity 8000 gross tonne hydrogen carrier can deliver about 1400MWh, after spending 3000MWh filling it up with a bunch of electrolysers then liquifying the hydrogen which you'd have to build a floating platform for. https://en.m.wikipedia.org/wiki/Suiso_Frontier

8000 tonnes of 200Wh/kg batteries is 1600MWh.

This is dumb, but hydrogen is much, much dumber.

Never overestimate the power throughput of a barge loaded with charged batteries.
I'd love to see something like this (hopefully smaller scale) used for maritime power. Power shipping itself with some semi-roving large power stores.

Assuming there's an electrified fleet worth serving seeming like a big challenge. It might probably need to be a bit more modestly sized/scoped. But this idea of large mobile batteries keeps being interesting to me.

This is very interesting, and makes me wonder if it's analogous to the old joke that the highest bandwidth pipe you could get was a semi full of DVDs.

I've been curious if someone would eventually run the numbers on something like this to see if it makes economical sense to transmit power in bursts like this.

Target range of 110 miles by 2030. Then 220 miles by 2040.

I'm not familiar with global sea route, but I'd imagine use cases for <100 mile route by small cargo ship is limited?

Unless the energy density multiplies quickly, it feels more like a vaporware.

The use case is to transfer energy from the main grid on the mainland to an outlying island. Most islands are not that far out.
It looks like someone took the "Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway" sneakernet idea literally.
Wonder if compressed air would be a better store on a ship.
The problem with compressed air power storage is the heat generated from the compression process, you never recover that so the losses are such that the efficiency overall is pretty bad
If there was ever a case for sails/kites, this is it
What exactly happens if even one of those batteries pops?
Sneakernet but for electric charge instead of bytes.
Absolutely ridiculous. Run a wire.
Or use the energy to disassociate sea water into hydrogen, ship the hydrogen.

They're doing this with the Sea Change hydrogen ferry in San Francisco https://www.sfchronicle.com/climate/article/san-francisco-fi...

Can you think of any issues with Japan, its steeply sloping sea surrounds, large number of earthquakes, and hard to access wires on the seafloor?

Is it prudent to think about a parallel means of energy transfer that works in the immediate aftermath of another scale 9 earthquake and disaster?

Or at least microwave energy stations
Have it drag a massive detachable trailer that is covered in solar panels.
Anyone want a 500 foot bomb in their port?
I was going to make a snarky comment about how this boat now enables rich countries to exploit desert nations rich in solar-energy.