alt.hn

1/1/2026 at 10:29:54 AM

Worlds largest electric ship launched by Tasmanian boatbuilder

 https://www.theguardian.com/australia-news/2025/may/02/hull-096-worlds-largest-electric-ship-battery-power-launched

by aussieguy1234

1/1/2026 at 12:21:16 PM

The Guardian article glosses over a few things that are actually interesting about this ship:

- It's made out of aluminum instead of steel. The resulting weight savings make it a bit more efficient. That's something this shipping yard specializes in.

- Because it is going to run in shallow water on the river Plate, it doesn't actually have propellers but a water jet propulsion system.

Fully charged did a video on the construction of this ship early last year: https://fullycharged.show/episodes/electric-ferry-the-larges...

The project of getting this ship from Tasmania to South America is also going to be interesting as well. It can't do it under its own power; it's designed for a ~50km crossing, not a trans Pacific/Atlantic journey. At the time, they were thinking tug boats.

by jillesvangurp

1/1/2026 at 2:54:03 PM

I'd wager they will use what is known as a 'Float-on/float-off' ship for transport... it's rather common actually-

It's a ship with a very low deck line that partially submerges itself, with the center of the deck underwater deep enough so the other vessel can 'float on' over the deck. They they pump the water back out, raising the deck above water and the boat on top it just rests flat.

They do this for some oil rigs as well.

https://en.wikipedia.org/wiki/Heavy-lift_ship#Semi-submersib...

by mk_stjames

1/1/2026 at 7:24:48 PM

That first image on the page is incredible.

by 3eb7988a1663

1/1/2026 at 1:56:11 PM

The relocation was the big question on my mind.

The other is: when will they charge? Does this ship not run at night?

by wepple

1/1/2026 at 2:21:21 PM

If it’s anything like the electric ferries that cross the Öresund beween Helsingborg and Helsingør, they grab charge while they’re unloading and loading at each terminal:

Each trip consumes approximately 1,175 kWh, which is nearly the same amount a residential home consumes in a month. In each port is a tower with a robot arm that connects the charging cable automatically every time the ship comes to the dock. The system charges 10.5 kV, 600Amp and 10.5MW. The batteries have a total capacity of 4,160 kWh, which means that we always have a surplus of electricity if for some reason we cannot load during a stop or if the transit takes more time than usual.

In Helsingör the ferries charge for approx. 6 minutes and in Helsingborg the ferries charge for approx. 9 minutes. This is enough to suffice for the journey across the strait.[1]

Side note: you can also charge your car on board from the boat’s batteries.

[1] https://www.oresundslinjen.com/about-us/sustainability

by robin_reala

1/1/2026 at 2:34:47 PM

10.5MW on demand is wild

by leoh

1/1/2026 at 6:49:24 PM

So in the Fully Charged video about this ship, the shipyard CEO just casually mentions the customer is looking at having 40 MW at each end.

by jasonwatkinspdx

1/1/2026 at 9:27:57 PM

It’s not that big when you consider many DC car chargers can deliver 0.25 MW.

So ”only” 42 car sized chargers for a massive boat, there are probably some massive Tesla superchargers sites that approach that.

by phire

1/1/2026 at 3:26:30 PM

Q:

> when will they charge?

A:

> The ship... will travel between the ports of Buenos Aires, Argentina, and Colonia del Sacramento, Uruguay. The two cities are 60 kilometers apart, a distance it is expected to travel in 90 minutes.

> Direct-current charging stations will be installed at each port... A full charge is expected to take just 40 minutes.

https://spectrum.ieee.org/electric-boat-battery-ship-ferry

by SideburnsOfDoom

1/1/2026 at 4:27:46 PM

Full charge is 40 but the charge for each journey is 6 / 9 minutes.

Big difference, since I imagine the turnaround time on a similar ICE ferry would be less than 40 minutes but more than 10.

by bryanlarsen

1/1/2026 at 9:31:09 PM

Indeed, the turnaround time necessary for unloading passengers, and loading the next lot is likely sufficient to keep charge.

by SideburnsOfDoom

1/1/2026 at 2:01:30 PM

Also: installing the charging infrastructure. Special docking requirements for the non electric Spirit Of Tasmania were a big problem.

by pjc50

1/1/2026 at 4:32:53 PM

I wonder if they could load batteries into it instead of cars and passengers?

I assume it’s too hard to be worthwhile, and probably still wouldn’t get the range.

by lostlogin

1/1/2026 at 8:14:47 PM

I think that makes a ton of sense, esp since you can retrofit diesel-electric ferries.

Skips expensive DC charging infrastructure, but does require to buy two batteries which can get expensive. Over time vpp / market arbitrage can pay for battery itself tho.

Also sacrifices some of the cargo capacity. I.e. for wellington - picton that’s about 4 rail cars or 6 semi trailers.

Edit: also smaller turnaround time.

by dzhiurgis

1/2/2026 at 8:48:34 AM

For one long haul trip at the start of its life, a generator might be an option too.

New Zealand should we well suited to electrifying everything, with a lot of good energy sources.

I can’t see the current government supporting anything EV, particularly across the Cook Strait, given the ferry fiasco to date.

by lostlogin

1/2/2026 at 8:45:59 AM

For one long haul trip at the start of its life, a generator might be an option too.

New Zealand should we well suited to electric ferries, with a lot of good energy sources.

I can’t see the current government supporting anything EV, particularly across the Cook Strait, given the ferry fiasco to date.

by lostlogin

1/2/2026 at 3:11:20 AM

Throw some big kites on it and sail it, use the jet propulsion just for vector control.

by seg_lol

1/1/2026 at 1:49:38 PM

Thanks for the video link, it's way more informative than the original article.

by merek

1/1/2026 at 3:25:09 PM

> The project of getting this ship from Tasmania to South America is also going to be interesting as well.

Indeed. As I remarked last time (1) "it's long distance and can be rough seas" They get to pick a good time of year, but either route goes past places known for storms and shipwrecks in the winter (June to September). Would you choose to go via Cape Agulhas or around Cape Horn?

It would be annoying to be ready to deliver the ship, but due to schedule over-runs, to have to wait 4 months for the weather to improve.

1) https://news.ycombinator.com/item?id=45844832

by SideburnsOfDoom

1/1/2026 at 12:22:30 PM

Article quotes `40 megawatt-hours of installed capacity.` - Surely this can get you pretty far from Tasmania to South America.

by tedk-42

1/1/2026 at 12:29:51 PM

apparently, 40MWh of capacity is enough to travel 40 nautical miles. The distance between Tasmania and South America is around 6,500–7,500 nautical miles.

by chii

1/1/2026 at 1:20:06 PM

For comparison, a wide body airliner needs ~0.15MWh to travel 1 nautical mile.

by amelius

1/1/2026 at 1:51:17 PM

A wide body airliner doesn't carry "up to 2,100 passengers and 225 vehicles".

by eesmith

1/1/2026 at 2:54:14 PM

It also does so in a medium where the main drag force is induced by air rather than water, which is probably a comparably significant factor

by verandaguy

1/1/2026 at 3:08:11 PM

It also needs to beat up that air enough to make the resultant forces overcome gravity acting on the airliner whereas the ship just gets to float there.

Apples to orages.

by potato3732842

1/1/2026 at 4:50:04 PM

Yup.

Or to structure it a the earlier comment: for comparison, it takes me about 0.000065 MWh to cycle 1 nautical mile.

That's a couple of apples.

by eesmith

1/1/2026 at 5:39:36 PM

You also aren’t doing so while carrying 2100 passengers sms 225 cars, I imagine.

by nandomrumber

1/1/2026 at 7:08:58 PM

Plus they are going to get very waterlogged cycling that nautical mile.

by nineteen999

1/1/2026 at 9:16:47 PM

Some dedicated cyclists will cycle in any weather.

by nandomrumber

1/1/2026 at 2:23:13 PM

I would be extremely surprised if the ship were designed to use 100% of its capacity in one way of its intended route.

by rcxdude

1/1/2026 at 2:30:11 PM

The drag on a vessel is orders of magnitude larger than the drag on a car.

by jacquesm

1/1/2026 at 3:34:52 PM

I've taken one of the electric roll-on/roll-off ferries that cross from Denmark to Sweden over the Øresund strait. Zero fumes, zero vibration, incredibly quiet. Awesome to see this tech being used for longer crossings.

by TinyBig

1/1/2026 at 5:09:33 PM

It took a bit of digging but it looks like the ship can operate for 90 minutes without recharging:

> ... the batteries will power eight axial-flow water jets driven by permanent magnet electric motors. These will be able to keep the ship going for 90 minutes before needing to be recharged.

> The ship’s permanent home will be the Rio de la Plata estuary, where it will travel between the ports of Buenos Aires, Argentina, and Colonia del Sacramento, Uruguay. The two cities are 60 kilometers apart, a distance Hull 096 is expected to travel in 90 minutes. Direct-current charging stations will be installed at each port and will draw energy from the two countries’ grids. A full charge is expected to take just 40 minutes.

https://spectrum.ieee.org/electric-boat-battery-ship-ferry

by djoldman

1/1/2026 at 5:52:05 PM

Calling it the largest electric ship seems wrong or at least requires extra specificity compared to nuclear aircraft carriers.

by phibz

1/1/2026 at 6:11:53 PM

The propulsion of nuclear-powered aircraft carriers isn't electric... it's driven directly from the steam produced by the reactors.

Edit: At least that's the case for US Nimitz-class aircraft carriers. Nuclear submarines apparently come in both types, with electric motors or direct drive steam-turbines, but I guess this ferry is bigger than any of those.

by jbotz

1/1/2026 at 11:16:59 PM

There have been diesel electric surface ships as well going back to WWII, although it hasn't proven a very popular design and they remain an oddity.

by jcrawfordor

1/1/2026 at 2:10:50 PM

I would like to know its price. Here in the Azores Islands there was a project to replace an ICE ferry with an electric one but they couldn't agree on the price with the boat builders. It went up to as much as 35 million Euros but it ended up being cancelled as that, apparently, wasn't enough for a ferry that can do 1-1.5 hour crossings with a dozen cars or so.

by cfn

1/1/2026 at 4:37:10 PM

Size of the ferry will make a big difference. A small ferry is going to cost a lot less than this 225 car ferry. My quick reading is the Azore ferries hold about 8 cars; that's a totally different class of vehicle.

My local ferry system has an electrification project[1]; the current active project is three 160-car hybrid-electric ferries for a total cost of $714.5 million. A NZ shipbuilder is probably more competitive than a US shipbuilder, and details matter....

This article says $200M [2] which is a lot lower than I expected, given it's a one-off and larger (I think) than the WSDOT 160-car ferries.

[1] https://wsdot.wa.gov/construction-planning/major-projects/fe...

[2] https://www.ro.com.uy/2025/10/16/nuevo-barco-china-zorrilla-...

by toast0

1/1/2026 at 6:47:02 PM

> NZ shipbuilder

Note that the shipbuilder from there article is based in Tasmania which is part of Australia. NZ isn't yet part of Australia.

by robocat

1/1/2026 at 2:16:09 PM

As a comparison, in my banana country they spent €7.7m on a beat up old Greek ICE ferry that isn't even up to local safety standards[0].

Compared to that, €35m or so for a new modern vessel doesn't sound outrageous.

[0] https://www.morski.hr/jadrolinija-za-7-7-milijuna-eura-kupuj...

by senko

1/1/2026 at 4:16:45 PM

I had no idea that would be the cost of a ferry albeit old. We have a massive problem with transportation between islands due to lack of ships/investment. For example, out of the 9 islands only three have daily voyages and right now even that isn't happening as one boat broke down and another is away on maintenance. We could do we a couple even old ones.

The main issue I saw here with the electric ferry was that 90% of the installed generation in the islands uses HFO so we would be charging the ferry with a fuel that pollutes more than the diesel used to run it.

by cfn

1/1/2026 at 5:00:25 PM

I’m curious if it would have made sense to build it as a hydrofoil. There are a couple of electric boat companies that use that to reduce drag, wake and improve comfort on-board. The software to keep things level is non-trivial, but I don’t know if it adds a lot of complexity to the build.

by bertil

1/1/2026 at 11:42:00 AM

Spent a few months down in Hobart sussing out an antarctic science degree- really cool marine industry nexus down there with world leading research, all of the antarctic operations, and this stuff. Definitely the most nautical feeling city in Australia

by t0lo

1/1/2026 at 4:21:34 PM

It looks like they could have mounted at least 100 solar modules on top, if not 200. That's 600-1200kwDC, given its flat, at 800kwp/kWh, that means for an hour of peak production, after losses, would do at least 300kwh for the smaller size and 600kwh for the larger size. If each trip is around 1150kwh and takes longer than an hour, more than half of the power required could be generated. As solar modules are solid-state devices, seems short sighted to not slam a system on the roof. PV modules are literally just glass sandwiches with wires and DC to DC battery chargers are very efficient. The weight would also be partly counter-acted by using the modules as the skin for the roof.

by ihaveone

1/1/2026 at 5:10:07 PM

Your math is far off. If you put 60kW (STC rating) of PV panels as quantity 100 of 600W premium panels on top, in Uruguay, it'll produce somewhere between 6800 to 8100 kWh per month if the panels are perfectly exposed to sun from sunrise to sunset.

If we say it's 7500kWh a month that's something like 250 kWh of production per day, which is a tiny drop in the bucket compared to the amount of energy needed to charge the ferry.

by walrus01

1/1/2026 at 11:17:16 AM

I hope that such a flat roof will be covered in solar

by NooneAtAll3

1/1/2026 at 11:55:56 AM

It should take around 50 hours to fully charge its batteries under ideal conditions. That is 5 - 10 days realistically. I guess it's impractical considering that it will ferry across the River Plate.

by red75prime

1/1/2026 at 2:40:39 PM

If it can charge while sailing there is no downside. At least as long as a substantial percentage of total charge can come from the integrated solar.

by teiferer

1/1/2026 at 4:08:37 PM

When Argentine gets enough solar over-provision, ship owners might make money by charging during negative solar prices.

by red75prime

1/1/2026 at 3:49:49 PM

> At least as long as a substantial percentage of total charge can come from the integrated solar

Yes, but that's highly doubtful. It doesn't work for EVs with panels on the car's roof - you don't get significant charge from it. It's far more practical to put the panels on a larger, fixed structure where the vehicles charges daily.

Sources e.g.

https://octopusev.com/ev-hub/why-dont-electric-cars-have-sol...

https://www.forbes.com/sites/billroberson/2022/11/30/why-doe...

https://www.reddit.com/r/NoStupidQuestions/comments/ykwd89/w...

by SideburnsOfDoom

1/1/2026 at 1:54:11 PM

Any flat surface on a ship that is designed for electric should be covered in flexible solar panels.

Why do this if it can’t fully charge the ship? To offset the costs of charging the ship at port, to provide longer range by providing a lower voltage power source for 12V DC charging (cell phones, iPads, 5w LED lights).

So the commenter is correct, she needs panels and the fact that this isn’t part of the launch shows that they were more interested in being first than practical.

by reactordev

1/1/2026 at 2:25:57 PM

It’s possible adding panels could reduce the range because they’re heavy and so high up on the ship.

by cush

1/1/2026 at 2:31:20 PM

Weight won't matter much (you typically only accelerate it once, and the additional drag is small), it is just that the surface area is so small relative to what's needed that it just doesn't move the needle.

by jacquesm

1/1/2026 at 3:36:54 PM

From the current top comment on this thread:

> It's made out of aluminum instead of steel. The resulting weight savings make it a bit more efficient. That's something this shipping yard specializes in.

According to that person, weight does indeed matter.

by arijun

1/1/2026 at 5:08:04 PM

Solar panels are also made from aluminum frames or can be flexible in plastic sheets. The weight is negligible.

by reactordev

1/1/2026 at 8:24:50 PM

Yes, the weight of the hull, which is immense. Compared to that some solar panels probably weigh about as much as the paint. It's still ship, not an aircraft.

by jacquesm

1/1/2026 at 9:25:48 PM

Also, thin film solar panels that can be stuck to a flat roof likely weigh less than the small portion of the battery capacity (250 tonnes of batteries total) they could theoretically substitute for.

If you were optimising for mass rather than ease of maintenance you'd probably put them on (despite the relative lack of surface area meaning you still needed to recharge at each end)

by notahacker

1/1/2026 at 5:12:17 PM

Drag is huge for boats, especially in seas and oceans that have tides and currents. Far more than a car... that also have to continuously burn oil to keep their speed, even on freeways.

by aziaziazi

1/1/2026 at 8:25:25 PM

See my other comment...

by jacquesm

1/1/2026 at 2:14:19 PM

It's not a long range vessel, but it should have a fairly long service life.

Additional weight and complexity on a one off boat would be more expensive than a seperate much more standard solar and battery system on land. And you might be able to get additional value out of selling electricity from an oversized storage.

It's not sensible to draw your system boundaries around the boat by itself; there is significant terminal infrastructure; and even grid electrical infrastructure to consider.

by servo_sausage

1/1/2026 at 5:11:00 PM

I disagree entirely about complexity. It’s not complex at all.

I don’t draw a boundary around the boat. I see a missed opportunity to power non-drive electronics from a renewable source such as solar.

by reactordev

1/1/2026 at 7:31:52 PM

Pintegrated panel design,cost, and maintenance can be more expensive than the puchace price of electricity. Putting pannels on regular ground is vastly more efficient.

This is kinda like saying everyone should wear solar hats to offset their home electric bill.

by s1artibartfast

1/1/2026 at 11:22:15 AM

Probably more efficient to keep inverters, panels etc on land.

by victorbjorklund

1/1/2026 at 11:54:09 AM

I’m not a sparky but would you need inverters if the panels are just for charging batteries? On the other hand, there is probably already inverters onboard to provide AC power to passenger power points.

by phinnaeus

1/1/2026 at 2:04:51 PM

No, you need some kind of DC converter to regulate voltage, but no inherent requirement to go to AC. Lots of small camping and off grid systems do that.

Although at the scale of a one off boat i would think it's cheaper to use the more widespread systems for bigger grid connected panel installations; so you are back to inverters.

by servo_sausage

1/1/2026 at 1:55:18 PM

You would be consuming fossil fuels to charge a ship when the sun is giving you energy for free.

At least capture some of that to charge some batteries or extend the length of your voyage.

by reactordev

1/1/2026 at 2:10:53 PM

The energy is not free, since the solar panels cost money and don't last forever. Even at optimistic prices, it's still something like 0.03 USD/kWh. Install them on a boat and they have to deal with constant vibrations, humid conditions, seagulls shitting all over them, etc etc etc.

I used to work on ships and almost everything constantly breaks down without constant maintenance. I bet it would be much cheaper to put the solar panels on land and charge the ship when it's in port.

by WJW

1/1/2026 at 2:44:56 PM

That may all be true, but there are other benefits that could make it worth it. For example it could be, in theory, self-sufficient forever if something else breaks down making it unable to maneuver. Then you can at least sit in the middle of the sea and have your heating and cooking and desalination working until you repair the propulsion.

by teiferer

1/1/2026 at 3:30:10 PM

You already have MWh of batteries for that.

by padjo

1/1/2026 at 4:05:54 PM

No you don’t because after a few days broken down, they are drained without solar.

by reactordev

1/1/2026 at 4:04:55 PM

I sailed around the world on a sailboat with solar. I know. It’s still better than none at all.

The energy is free. To capture it costs a little bit of money.

by reactordev

1/2/2026 at 9:09:59 AM

It is big difference between mounting solar on your personal sailboat and installing them on a large commercial passenger ship. The regulations are totally different.

by victorbjorklund

1/1/2026 at 4:29:29 PM

There’s something funny to me about taking your experience with solar on a small sailboat and extrapolating this to a commercial ferry that would need a very large solar installation that’s funny to me. Something tells me the experience isn’t transferable.

by vlovich123

1/1/2026 at 5:05:08 PM

The point isn’t to power the main drive, the point is to preserve energy used elsewhere on the ship.

My experience sailing and dealing with vessels from 30ft to 180ft give me a perspective that you probably don’t.

Providing solar panels along the roof would give the ship a few KWh of power that would otherwise be drawing from the main batteries. This would extend the range of the ship by 5-10%.

by reactordev

1/1/2026 at 7:07:12 PM

For how much cost? The range of the ship is already handled well by the batteries. An extra 5-10% isn’t going to meaningfully add value nor reduce fuel costs. There’s no way to recapture the capital expenditure such solar panels would require.

by vlovich123

1/1/2026 at 10:25:48 PM

The 5-10% number is completely invented. I doubt it's half as high as 5%, but until and unless someone does the maths, there's no point in speculating.

The math has been done many times for solar panels on the roof of cars, and it's not worthwhile. Ships are not the same though.

At any rate, it's inevitably far more sensible to put a larger solar panel + battery installation at a fixed place on land, and charge vehicles from that.

by SideburnsOfDoom

1/1/2026 at 10:13:08 PM

Adding range reduction turn around time. Ship is making money while it is moving, not while it’s charging. Also why roro batteries make most sense.

by dzhiurgis

1/2/2026 at 6:22:56 AM

The journey it makes is 90 minutes and it can charge for that journey in 8 minutes. Offloading and onloading the thousands of passengers (and 220 cars!) takes much longer than the 8 minutes for the battery to charge.

by gbear605

1/2/2026 at 3:48:55 AM

I’m assuming that the boat gets charged fast enough for one way trip while passengers are loading. There’s no need for much more capacity beyond that.

by vlovich123

1/1/2026 at 7:42:44 PM

Where are you getting your 5-10% numbers from?

The ship battery is 40,000 kwh and uses at least 10,000 kwh per crossing, with 10 minutes to recharge. A handful of kwh are negligible because this isn't a sailboat.

The electricity sector in Uruguay has 98% renewable power

by s1artibartfast

1/1/2026 at 10:11:31 PM

Catamarans are perfect for scaling up solar like this. Even 40ft is enough to power it entirely off sol at hull speed.

by dzhiurgis

1/1/2026 at 10:56:10 PM

I wouldn’t go that far. Not at hull speed. But a good fraction of it. The silent 60 for example.

Full throttle you’ll be out of juice in a week. Hull speed maybe a month. Depending on wave conditions. But going, stopping, having lunch, enjoying the day, going again, enjoying tomorrow, you can be out there as long as you have provisions.

by reactordev

1/1/2026 at 6:26:50 PM

Read again. I said you can put the panels on land where it is 100x easier and cheaper to install them vs on a ship. Solar panels are not fossil fuel.

by victorbjorklund

1/1/2026 at 2:28:08 PM

Why don’t electric cars and trucks have solar panels then?

by cush

1/1/2026 at 4:07:25 PM

Oh you mean like the Aptera or the Hyundai Ioniq 5? They do have solar panels built in. Prius Prime as well. These aren’t powerful enough to charge the main drive though, not enough surface area and voltage.

by reactordev

1/1/2026 at 6:27:36 PM

But why not put it on a Tesla if it will be so much more efficient than putting the same panels on your roof of your house and charge your Tesla with that?

by victorbjorklund

1/1/2026 at 6:30:53 PM

Because they want to sell you the cheapest car possible for the most money possible, sell you a home charging unit, sell you solar shingles, sell you a new power plant for your home to go with those shingles. They are not in the business of making their cars efficient, only making the cash flow efficient.

by reactordev

1/1/2026 at 6:46:50 PM

What stops you from slapping a solar panel on the roof if it is the most efficient way to charge an EV?

by victorbjorklund

1/1/2026 at 7:03:12 PM

the fact that many new electric cars do have solar panels, I fail to see your reasoning. A solar panel isn't going to provide you with enough energy to drive. Merely enough energy to trickle charge your batteries.

Now, should you run out of charge during your drive, you simply have to wait a while and you'll have enough to get you to a charging station. Or you can walk, taxi there. On an ocean or channel crossing, you don't have that luxury and must rely on other ships if you run out of charge. The point I'm making is that any electric vehicle should incorporate solar panels into the design to minimize it's dependence entirely on the batteries and can extend it's time doing what it's designed to do.

As solar panels advance and the wattage increases, this will be more and more important as it will open up new avenues for transportation. Like the solar LSA plane "Solar Impulse" that can fly indefinitely.

by reactordev

1/1/2026 at 9:24:04 PM

> the fact that many new electric cars do have solar panels

Not true. Not many at all, in fact vanishingly few. I don't know of any EV currently on sale where it is standard. Because it's not practical. See comment above.

> Now, should you run out of charge during your drive, you simply have to wait a while and you'll have enough to get you to a charging station

Or not, as it adds a few miles of range per day of charging. You're far better off using the V2L capability of another EV to bring the charge to you.

> As solar panels advance and the wattage increases, this will be more and more important

No, it won't. Even at perfect panel efficiency , there just isn't enough room on a car roof to charge a car in reasonable time. Solar panel improvements won't do it.

https://news.ycombinator.com/item?id=46454978

https://news.ycombinator.com/item?id=46455027

> Like the solar LSA plane "Solar Impulse" that can fly indefinitely.

You can already drive an EV indefinitely, by mounting a much larger surface area of solar panels on your house, and charging your car from that regularly, with or without an intermediate battery that allows you to charge the car overnight. This is proven and practical, unlike solar panels on the car. For solar panels on a car, the math is that it just never will be practical.

The math: https://youtu.be/7L1_zvqg73Q?t=590

by SideburnsOfDoom

1/1/2026 at 9:36:10 PM

Nothing stops anyone from doing this, except that it's ineffective. See comments here https://news.ycombinator.com/item?id=46455027 https://news.ycombinator.com/item?id=46454978

This guy's impractical homebrew rig gets "20 to 30 miles per day" when unfolded and the car is not in motion. That unfolding is necessary as there just isn't enough surface area on a car roof to make it worthwhile.

https://www.dartsolar.com/

https://www.reddit.com/r/TeslaLounge/comments/194ajsm/my_tes...

It's still far more practical to 5x or 10x the number of solar panels, mount them on a fixed structure like a house roof, where they never have to be folded or moved around, and park the car next to it, to charge.

by SideburnsOfDoom

1/1/2026 at 9:23:07 PM

The Aptera vehicle is vapourware and likely always will be. It's not a practical vehicle that is on sale.

Solar roof on Ioniq 5 and Prius is an option, not standard. And it's rare. In fact, I've never seen it or even heard of it until I looked up what you were saying. And for the Ioniq 5 solar roof, it seems that it's not even offered at all in some countries.

The Prius one is "Offered as an option on the range-topping XSE Premium trim". Far from standard. This roof literally adds up to 4 of miles of range on a good day. (1) So it's a high-end gimmick that has niche use at best on a car, when compared to a fixed solar / battery installation situated where the car is parked.

It won't be any more useful on a boat.

1) https://www.reddit.com/r/electricvehicles/comments/13w5cb1/o...

by SideburnsOfDoom

1/1/2026 at 3:38:02 PM

[dead]

by OfficeChad

1/1/2026 at 10:06:22 PM

I doubt it but it deff goes well with roro batteries too.

by dzhiurgis

1/1/2026 at 1:46:45 PM

more efficient to leave surface unused?

by NooneAtAll3

1/1/2026 at 6:32:34 PM

Yes, it is more efficient to install it on land. The installation will be cheaper, maintainance will be cheaper and the panels will last longer.

by victorbjorklund

1/1/2026 at 2:07:44 PM

More efficient to spend the same amount of money on shoreside panels with lower installation costs.

by scraptor

1/1/2026 at 2:21:52 PM

Do you have solar panels on top of your head? If not why do you leave that space unused? Space being there is one of the worst possible reasons. That bloats designs and makes them expensive to build and maintain.

by jeltz

1/1/2026 at 2:06:27 PM

Same reason EVs rarely have solar panels; adds weight and complexity, making it more expensive than putting the panels somewhere less wet and salty.

by servo_sausage

1/1/2026 at 3:54:45 PM

... and doesn't add significant charge.

> The surface area of a standard car simply isn’t big enough to hold the sheer volume of solar panels that would be needed to capture a meaningful amount of energy from the sun.

https://octopusev.com/ev-hub/why-dont-electric-cars-have-sol...

> there just isn’t enough space on top of cars to make a meaningful contribution to the charging needs of the battery

https://www.forbes.com/sites/billroberson/2022/11/30/why-doe...

The same must be true of a ship.

Put the larger solar panel installations at the places where the vehicles charge.

by SideburnsOfDoom

1/1/2026 at 2:11:08 PM

Talk to a marine engineer about the overhead (equipment, training, emergency procedures, etc.) of adding a small-scale solar plant to all the things that they've already got to deal with on a ship.

And recall that this bridge - https://en.wikipedia.org/wiki/Francis_Scott_Key_Bridge_(Balt... - will need a multi-billion dollar replacement, because the tiny engineering staff of a huge freighter could not diagnose and correct a surprise electrical failure. Within the maybe 3 1/2 minutes between the initial fault, and when the collision became physically inevitable.

by bell-cot

1/1/2026 at 11:22:15 PM

Solar roof is a bunk idea. In case of cars, trucks and this ferry you can gain whole 1-3 additional minutes of operation per whole day of perfect solar radiation.

by rasz

1/1/2026 at 2:19:30 PM

250 tonnes of batteries…

by cush

1/1/2026 at 7:02:56 PM

And they could have called it "Androids dream" but didn't....

by Frenchgeek

1/1/2026 at 9:39:25 PM

How many km does it operate ?

Edit : 50 km according to another comment

by maelito

1/1/2026 at 1:58:28 PM

[dead]

by EB-Barrington

1/1/2026 at 11:53:14 AM

Ugly as hell as far as ships go. Ugly as hell like almost all new cars, trains and buildings.

by DemocracyFTW2

1/1/2026 at 12:10:42 PM

Does anyone have a feel for how heavy the weight of an equivalent oil(?) driven ship would be? It has the big number for the weight of batteries, but I've got nothing to compare against.

by trebligdivad

1/1/2026 at 2:35:31 PM

700-ish tonnes - it's in the wikipedia article:

"In 2020, Buquebus originally commissioned Incat to deliver a new ship to use dual-fuel propulsion, capable of operating on liquefied natural gas and diesel, with around 400 tonne of main engines, 100 tonne gearboxes, 100 tonne cryogenic fuel tanks and 100 tonne fuel."

https://en.wikipedia.org/wiki/China_Zorrilla_(ship)

by sparklysoup