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Sweden's new car carrier is the world's largest wind-powered vessel (cnn.com)
136 points by krn 5 days ago | hide | past | favorite | 88 comments

> is the world's largest wind-powered vessel

Nothing but CGI models. Surely a news agency as reputable as CNN can get the nomenclature right here?

It will be the world's largest wind-powered vessel once built in 2024.

There is a 7 meter scale model to verify the design.

A lot less than "being the world's largest wind powered vessel right now", but also a lot more than "just CGI"

Oceanbird probably is not a CGI only product. If you check the startup behind it started from KTH university then you and follow the related people in there you can see it is just not built but it is a product of so much simulations. I am not sure if it works out but the idea is more robust than one might assume initially.

CNN has a reputation alright, but it's not for depth or accuracy.

Which one has a reputation for depth & accuracy?

None. That's the sad reality of journalism in America.

The Economist?


That was your takeaway from the article? Nitpicking the grammar?

That's not nitpicking the grammar. It changes the meaning of the sentence. And if that's the only sentence you read you'd have no way of knowing it's wrong.

This is fantastic. Shipping goods is one major source of CO2 and other pollutants, as most ship engines are way dirtier than any car engine. If this concept works out, we have an almost magic bullet to cut ship emissions by 90%. And at that level, suddenly other concepts for the remaining motor power required become feasible. Those wings could be covered with solar cells for electric populsion and ships can carry large batteries. Or biofuels, hydrogen etc. Not only the emissions, but the requirement for motor powers have been cut by 90%.

On the other side, as someone who likes sailing boats of all kinds, it is just gorgeous. Imagine the seas populated by those great ships.

> Shipping goods is one major source of CO2 and other pollutants, as most ship engines are way dirtier than any car engine.

This is only kind-of true. Ship engines are dirtier in the sense that they produce worse NOx/SOx (causes of acid rain) and particulate matter (causes of haze and breathing issues). These issues are serious, but they have led to countless articles with very misleading headlines like "Big polluters: One massive container ship equals 50 million cars"[1].

For global warming (CO2 and other greenhouse gases), shipping does create a decent fraction of emissions (~2% of manmade co2 emissions in 2018[2]), but nowhere near what land-based transport creates (trucks+passenger cars put out roughly ten times what boats do [3]). Attempts to address the particulate/sox/nox has included LNG powered ships[4], which allow unburnt methane to escape, which results in worse GHG emissions (but less of the "emissions" that allow headlines like "shipping is as bad as 50 million cars!"). And if you look at a different statistic, ocean shipping of goods seems almost responsible (eg, ocean shipping has the lowest "CO2 per tonne per km", far lower than rail/truck shipping[5])

All that said, reducing GHG emissions from shipping is great and necessary. I hope this project works out.

[1] https://newatlas.com/shipping-pollution/11526/

[2] https://maritimesky.com/2020/08/05/imo-has-published-its-4th...

[3] https://www.transportation.gov/sustainability/climate/transp...

[4] https://theicct.org/news/fourth-imo-ghg-study-finalreport-pr...

[5] https://timeforchange.org/co2-emissions-for-shipping-of-good...

I was in a very interesting presentation once about the impact of ships on clouds [1]. There is more depth into the impact of these vesels compared to only the amount of carbon emission. But honestly I am not expret, I found it intreresting that for example the shipping from europe to USA had some impact in the amount of clouds in nortern africa. Although, I cannot find the presentations I saw.

[1] https://earthobservatory.nasa.gov/images/91608/signs-of-ship...

Regulation has already lessened ship sulphur emissions a lot. And it is being tightened in other ways too.

IMO 2020:

> The global sulphur limit (outside SECA’s [SOx Emission Control Areas]) dropped from an allowed 3.5% sulphur in marine fuels to 0.5%.

> Over 170 countries have signed on to the changes, including the United States [https://www.imo.org/en/About/Membership/Pages/MemberStates.a...]

We really don't need this concept to work out in order to have clean shipping. We've had the technology for 70+ years, we just haven't implemented it because oil-fired ships are cheaper: https://en.wikipedia.org/wiki/Nuclear_marine_propulsion

Certainly cleaner than oil-powered. But doubtfully cleaner than wind.

For wind you don't need mines, and extremely expensive storage facilities. For nuclear power you do.

Edit: obviously such a ship needs mining to get the metal to make such a ship, but so does a nuclear ship: after that, the wind-powered ship sails virtually for free forever, whereas the nuclear ship needs a small stream of plutonium in- and a small stream of highly "dirty" waste going out.

Consider however that a modern sailship needs a thermal engine for practical and safety reasons: you want to be able to avoid storms, calm periods or inconvenient winds that can make you drift hundreds of miles from your original destination, all of these big problems during the Age of Sail.

This is in fact why we abandoned sailing ships for merchant fleets: they run on the Sun's free nuclear fusion energy, but they are very inconvenient! So a modern sail ship will need to use its engine, and therefore I'm not sure they would be cleaner than a nuclear fission ship.

No ship sails forever. And given the amount of energy you get per kilogramm, nothing beats nuclear which is why the waste stream for anything that is nuclear-powered is extremely small.

I‘m also pretty sure that even a sail ship will have fossile-powered backup generators. No one is going to design such a big ship with no additional backup power supply and certainly those aren’t just batteries.

I don’t understand why people here still keep coming up with arguments against nuclear when countries with a large share of nuclear in their energy mix have the lowest emissions in their energy sector.

Oh, and the waste isn’t really a problem. In fact, nuclear waste is one of the best types of waste.

See: https://www.energy.gov/ne/articles/5-fast-facts-about-spent-...

I am very much for nuclear power. Especially the new generation of generators (with that said as someone pointed out there is problems with mining the fuel). But even with that said, that doesn't mean I would automatically be for putting it on a ship. One of the first thing I would say about nuclear power plants is to out them in places with a stable environment (maybe not places with earthquakes or huge storms) and putting it on a moving ship is kinda spitting in the face of that. I mean I might be wrong, havent looked very deep into marine nuclear but it feels scary when thinking of how often ship disasters happen. I think convincing people of nuclear on land is a large enough endeavor.

The US Navy has safely operated hundreds of marine nuclear reactors for 70+ years without any major issue. The technology is there if we actually wanted to stop polluting the planet.

The crew, maintenance, processes (including security) of US Navy subs is at a vastly different level from a typical merchant ship.

I agree with the concern about crew qualification, but maybe at least convert the worst offenders? The Guardian said [1] that "just 15 of the world's biggest ships may now emit as much pollution as all the world's 760m cars". Why not convert those 15-20 biggest ships to nuclear (with a UN or IAEA compliment aboard if you want)? I believe this could be a huge win for the environment achievably today with mature technology.

That was a story from 2009, and it was referring specifically to sulfur dioxide rather than all air pollution:


The high SO2 pollution was because heavy fuel oil used in oceanic shipping could have a very high sulfur content, up to 4.5%. The global limit has been lowered to 0.5% this year. In designated Sulfur Emission Control Areas the limit has been lowered to 0.1% since 2015.


The sulfur dioxide emissions from shipping have been slashed since that Guardian article was written. Other air pollution from shipping was not greater than that from cars in the first place.

Why would you trust cost cutting shippers with nuclear reactors?

Install catalysators instead.

Cool. Let's start by storing the waste in your backyard. Where your kids play. Let's see how you keep defending that "best type of waste" position while pushing your kids' wheelchair when they are on chemo.

Edit: To everybody downvoting me here, it's easy to say that it's the best type of waste as long as it's somebody elses problem.

To which I want to add: nuclear waste is the worst type of "somebody elses problem".

Not just geographical, as with most "NIMBY". But in time. It takes (tens of)thousands of years before it is no longer anyones problem. To put htat in perspective: if the egyptian Pharao's had decided to power their enterprice with nuclear power and store the waste "in a place up north where no-one lives", western europe would have large uninhabitable places - still.

> Shipping goods is one major source of CO2 and other pollutants,

It's less than 4.5% of CO2 emissions. Incredibly low good compared to the volume of goods and the benefits.

You can remove other pollutants with regulations. Requiring exhaust scrubbers or using other fuels has worked miracles in EU.

You can reduce CO2 emissions even more with slower speeds, thinner ship shape and cleaning the bottom of the ship regularly.

Getting rid of 4% of the total human CO2 emissions is huge. On top of that pollutants like fine particles. Switching to mostly-sail powered shipping reduces all emissions of a ships engine by 90% in one big step, the remaining 10% are even easier to clean up, as scale matters.

The figures are overly optimistic here. As a sailor, i'm certain that no one is crossing the Atlantic in 12 days at 10kts. The fastest cruiser- performance catamarans in the annual ARC Rally, sailing with the tradewinds from east to west are taking 12 days at 15kts daily average. (50% faster boat speed than this ship). And they are very experienced sailors with expert weather guidance.

And the winds when coming from americas back to europe are often against you, which is likely to make the trip 50% longer. (Tacking longer distances)

When you take the upper c02 level forecast for this ship, and assume a more realistic 20-25 days for this ship.. suddently the c02 savings are only around 50 to 60%

The sails are 260 feet tall, they say they measured the winds at that height on previous crossings, maybe the winds up there give them some advantage, maybe a more direct route? Just guessing.

Another thought is they can use the engine and the sails at the same time, possibly avoid long tacks but still getting fuel savings. I used to have a small sailboat with an inboard electric motor. You can do neat things with both available, the electric motor needs no warmup or startup and I could add a little push here or there if needed, or use both together.

>the sails can be retracted to 195 feet in order to clear bridges


Didn't think it looked like it would fit under the Houston Ship Channel bridge last month.

>Wind Power Breezes Back into Shipping with New RoRo Concept https://news.ycombinator.com/item?id=24458271

Also take into account the latitudes for sailing versus motoring. I don't know what shipping corridors typically are for diesel-powered cargo ships, but I doubt they go down to the tradewinds.

On the other hand, a 650' cargo ship can handle a lot more weather than a 40' sailing sloop or catamaran, so perhaps sailing the North Atlantic is more feasible.

They're not optimistic for the North Atlantic. Those aren't favorable routes for cruisers because of weather and predominant wind direction. But if you have a massive vessel like this, the North Atlantic is a great route and a lot shorter.

Agree. Look at windperfect. Seems most other commenters have never sailed. Mother nature is unpredictable and having backup power in squalls is important for safety

Here the prototype (made by partner KTH) having mounted the first wing on top of the model while testing:


There is also a video showing the setup and operation. Released just two days ago...

To clarify what KTH is:

KTH Royal Institute of Technology (Swedish: Kungliga Tekniska högskolan), abbreviated KTH, is a public research university in Stockholm, Sweden.


The problem with this is the diesel powered boat delivers, on average, 1,142 cars per day. The wind powered ship, being slower and with a slightly lower capacity, delivers 583 cars per day. Therefore, to deliver the same number of cars, you need two of the wind powered ships.

This extra 35,000 ton ship will be offset by saving 100 tons of CO2 per day (120 tons created by the diesel, minus ~20 tons created by the two sail ships). Is this worth it? How much CO2 does it take to build a 35,000 ton ship? And then of course the cost of a ship vs. diesel fuel.

Plus I presume the sail ships are now dependent on weather, which introduces logistical problems.

I suspect that coating the top of the diesel ship with solar panels and using the energy to supplement or replace the diesel engines might be a better use of resources?

> Is this worth it?

Maybe it is, maybe it isn't. But if you keep replacing links of the supply chain with green alternatives, then it must eventually reach a point where you come out ahead. Eventually the energy for building ships will come from renewable sources.

Trying to tackle everything at once on the other hand may lead to paralysis.

I never thought about it like that before, makes sense. Thanks.

>diesel ship with solar panels and using the energy to supplement or replace the diesel engines might be a better use of resources?

Imagine having the sails be photovoltaic for them to become a dual-energy source themselves.

Plus you need more than two ships anyway, at least one for backup if not simultaneous return voyages.

Such a ship has probably an expected life of 40+ years so the CO2 savings of the wind ship vs the diesel one are at most (the ship won't be at sea continuously) about 1.5 million tons.

You make good points, and I don't know the answer, but a meaningful comparison should indeed be made over the ship's entire lifetime, from manufacture to disposal.

Just a thought experiment for the numbers on oil tankers. The big ones carry 2,000,000 barrels of oil, which translates to 860,000 tons of CO2 produced from their cargo.

As to fuel, the bunker fuel used by cargo vessels is really dirty.




There's probably a lot more to the calculation too. I can imagine the wind-powered vessel could have a longer operational lifetime and require less maintenance since there's no combustion. Then again, if the mechanism is fragile it might be the opposite. I think it's still valuable to put this into production and iterate on better and better designs as we learn. Even if this first try can't make the math work.

I my experience sailing, anything that moves will break fairly quickly, anything that doesn't move can break to. I imagine the forces involved are an order of magnitude higher than for a motor, simply b/c motors are comparatively small.

What if we do wind/solar hybrids?

While double the ships is more costly to procure, it’s more flexible and fault tolerant, so there are benefits!

Ultimately I think the question is, what is the price difference to transport a car, and if higher would customers pay more?


> Can we challenge the assumption we need as many cars delivered in the future as we do now?

Personal transportation is a key driver of economic growth and prosperity. We should leverage technology to ensure that the cars that people need become ever more clean, environmentally sustainable, and affordable.

Personal transportation doesn't mean we need exactly the amount of cars we do now. One scenario is autonomous taxi fleets significantly reducing the need for personal vehicle ownership, especially in cities where the majority of the population lives.

Plenty of talk about CO2 and green energy etc. Didn't see anything about the actual fuel costs saved.

According to the article, the equivalent ship would use 40 tons of fuel per day and cross the Atlantic in 7 days. Assuming this is bunker fuel at approximately $340/ton, the total savings would be $11200 USD.

With an added delay of 5 days, I can appreciate why this hasn't been attempted for purely economic reasons. Who knows what the actual costs and maintenance will add up to in the end?

The real problem with shipping isn’t the CO2 emissions of the fuel as much as the dirtiness of the fuel. It doesn’t seem crazy to gamble that this will eventually be restricted heavily, particularly in Europe, and thus that it will become more expensive (fossil fuel ships aren’t going away anytime soon, but we could definitely see greatly increased standards).

The article does concentrate on CO2, but I suspect that’s not the real story here.

Starting in January 2020, marine fuel’s sulfur content was reduced 7 fold, from a max of 3.5% before to 0.5% now, out in the blue waters. Within 100 miles of the US coast, the limit has been 0.1% since 2015.


Regulation could change this equation very very quickly.

There might also be unexpected sweet spots for this kind of technology. Things that come to mind:

- shorter stretches where speed is a bit less of an issue

- promotional value for the brands transporting their goods this way

- ...

Bunker fuel should be taxed at at rate that makes its use prohibitive.

That would prevent innovations which could make bunker fuel more efficient or clean.

Once the tech is there, working, viable, EU will start a gradual move towards tax optimisation to include the externalities and level the playing field.

The article does not really explain how it works. From my naïve understanding, those wings sails do not seem to be ordinary wings but are shaped like the ones in airplanes. When they are rotated to the right angle given the wind direction, the vessel is pulled forward. The topic reminds me of the Flettner rotor [1] and other wind-assisted propulsion systems [2].

[1] https://en.wikipedia.org/wiki/Flettner_rotor & https://de.wikipedia.org/wiki/Flettner-Rotor

[2] https://en.wikipedia.org/wiki/Wind-assisted_propulsion

They work just like normal sails. A sail is just a wing sideways. It moves the ship by generating lift.

The ship moves forward when the angle of attack is adjusted correctly. See the picture: https://en.wikipedia.org/wiki/Point_of_sail#/media/File:Poin... The ship can't move directly against the wind, but it can close-haul 45 degrees against the wind assuming it has enough keel.

> The ship can't move directly against the wind

Is that a fundamental physical limitation, or would it be possible to come up with a design that allows moving directly against the wind (while being fully wind-powered).

(EDIT: ok, answering my own question: I guess you could anchor the ship and use a wind-turbine to charge a battery, then use that energy to move a bit, anchor again and repeat)

Wind turbine ships can sail directly into the wind. There's no need to anchor or store energy — you can just power the propeller directly from the turbine.

Not sure about that. Normal sails "bend" away from the wind and thus have a much stronger lift. This concept's sails are "beant" outwards and would lose much of the wind's force. This source [1] states that "The futuristic sails are like airplane wigs using the same level of aerodynamic technology" which would imply that they absolutely do not "work just like normal sails".

[1] https://www.maritime-executive.com/article/swedish-collabora...

Wingsail works with the same principle as conventional sail, it's just more efficient (hang gliders use the sails to fly).

Wingsails like this generally have a 3x to 5x advantage in lift/drag ratio for equal area.

> The article does not really explain how it works.

It's a sail. Being rigid instead of a piece of cloth doesn't change the basics of how it's working.


I didn't get the 40 tons of fuel makes 120 tons of CO2. The optimum fuel/air ratio is 14.5:1 for a diesel fuel. Is bunker C fuel burnt at 3:1 ratio? Sounds wrong.

Hydrocarbons are mostly C by mass. Carbon dioxide is 27% C, 73% O (one C atom to two O atoms). So the output of one ton of hydrocarbons (coal, gasoline, paraffin, it doesn't matter) is three tons of CO2.

Some of the rest of the 14 parts air goes to burning the H atoms, which don't weigh much, and producing water. Most of it is nitrogen which isn't burned.

In an ideal burning reaction in atmospheric air for C4H10 you get 4 CO2 and 5 H2O (and a bunch of N2) at fuel ratio of 15:1.

So for 40 tons of fuel with C4H10 you’ll get around 120-130 tons of CO2.

Once you do the math and convert from mol for each product to KG it more or less comes out right. Hydrogen is 2 g/mol, Oxygen and Carbon are 16 and 12 respectively. So you are essentially tripling the mass simply because you are adding a heavy molecule (oxygen) to the mix.

Wouldn't it make more sense to equip the ship with vertical axis wind turbines that either drive a propeller or a generator which drives an azipod? Doesn't matter which way the wind blows you can still generate energy. Less efficient sailing headwind of course but you could still do that without tacking, too.

Conversion losses make the generator idea lackluster. Vertical axis turbines would be a lot of complexity and weight for dubious benefit. Freestanding wingsails like this already have very wide response to wind. Tacking isn't that great of a concern.

> the sails can be retracted to 195 feet in order to clear bridges or withstand rough weather.

That's awfully close to the clearance under many bridges. The SF Bay bridge for example, which has to be crossed to reach the port of Oakland, has a clearance of 220 ft.

Engineers work in terms of 10 thousandths of an inch.

25 feet of difference is massive.

I'd love to watch a ship clear a bridge by 10 thousandths of an inch.

Well, not quite like that, but here's Allure of the Seas passing the Great Belt Bridge in Denmark, with a few feet of clearance (I think 2 or 3, but I'm not certain - sources are unclear.)


That one rivet that didn't quite go all the way in...

Oh, this is amazing! I don't think I've seen solid sails before, although now that I think about it, it makes perfect sense.

Hopefully this kind of design can be adapted to more ships and maybe even retrofitted to existing vessels.

They are way more efficient than conventional sails, although a lot less practical. The F1 of sailing uses wing sails.


They can be less practical but they can also be more practical. The only autonomous sailboats in the world use solid wingsails, but with a different control scheme than traditional sailors are accustomed to. This allows them to be operated without any of the complexity or danger that you'll see in an AC50.

Closest I can come to think of is the Maltese Falcon, but it doesn’t have solid wings, but still pretty unconventional in similar ways: https://www.marineinsight.com/boating-yachting/maltese-falco...

Kind of funny that this "clean" ship is being used to transport cars.

By the time the ship is in service, the cars it transports might be all electric.

Wild idea: Power the ship with the batteries in the 7000 cars it carries, partially (speed up) or fully.

One cable per car to its charging port - power can be transmitted in that direction too.

Edit: Quick reality check: About 500 MWh from the batteries. An oil-based ocean crossing of a similar sized vessel uses 280 tons oil, corresponding to about 3 GWh.

So, meh. Probably not worth all the hassle - the cabling, recharging the cars after the crossing, dealing with various extra fire risks, etc.

i still like this idea, yes you basically need 7000 charge ports, according to this : https://www.google.com/search?&q=how+much+does+an+electric+v... , you can install one for ~500 - $1k, that's an additional $3.5m million on the price tag. Then to install the additional wiring and some method of recharging cars on the boat at port you'd probably need at least half that so an addition 1.75 for a total of probably ~5 - 6 million. Also you wouldn't necessarily have all these batteries on the return voyage unless you were shipping cars back as well. If you cover the boat in solar you would get additional energy.

Yeah, perhaps it could make sense economically down the road, once it's all BEVs that are being shipped. It's really hard to to that calculation as an outsider though. Maybe this project should work with a BEV company to do a preliminary feasibility study of this. They've probably already thought about this though.

Edit: It will also become more feasible with energy density increases in batteries. I hope it's not entirely unrealistic to expect a doubling in the next 20 years.

About your edit: If you mostly sail, you cut the energy requirements from the engines by 90%, according to the article. Suddenly alternative power sources, like the car batteries, become literally 10 times more feasible :). Add to the batteries any internal batteries the ship might carry and solar on the wings, and you can reduce the need for other fuels further, even if you are not able to replace them alltogether.

The batteries could be used to make it use 0% oil - use the batteries in the ports and in emergencies. Is going from 90% to 100% reduction worth the hassle? Probably not.

I was first hoping the batteries could be used to reduce the extra crossing time (12 days vs 7 days for oil) significantly, but I'm guessing it would only reduce it by 0.5-1 day or so.

Ship engines are at most 50% efficient[1]. Still a away to go though.

[1] https://www.nuclear-power.net/nuclear-engineering/thermodyna...

That might be an idea, at least for the loaded parts of the travels. Also, for a ship mostly driven by sails, solar-electric propulsion for the rest suddenly becomes more feasible.

After clicking 5 times on "Object to Legitimate Interest", I lost my own interest.

Damn you OneTrust! Why can't you just respect GDPR without needing to constantly invent new dark patterns?

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