Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Maersk installed 100-foot-tall rotating sails on one of its tankers

wsj.com

Post reply on HN
Print view View original

71–80 of 233 posts

Re: Maersk installed 100-foot-tall rotating sails on one of its tankers

#71

Post by liber8 »

abtinf wrote: post #18

Some years ago I read The Box by Marc Levinson, a history of containerized shipping. Highly recommend it. If you live in SF and have wondered about the numerous barely used piers, this book explains their history as well - and why the major container terminal ended up in Oakland instead. One of the painful early lessons for the industry was the discovery that minimizing operational costs (particularly fuel and mainte…

I'll second this, The Box is fantastic. It sounds like a dry subject, but Levinson did a fantastic job of telling the story of how containerized shipping changed the world.

Re: Maersk installed 100-foot-tall rotating sails on one of its tankers

#72

Post by ballenf »

taneq wrote: post #48
robfitz wrote: post #9

Earlier quoted context omitted.

They claim 7-10% reduction in fuel usage, with fuel making up 60% of their total costs. Given that they soon expect to be spending $5 billion/year on fuel for 800 ships, fuel spend is a bit north of $6 million/year for an "average" ship. But size seems to vary widely (they note that only the 80 of their largest ships are being considered for these sails). At an installation cost of $2 million, saving 10% of an "avera…

I think that's something we lose sight of in software sometimes, where we're used to some token effort improving performance by 10x or more. In the real world, if you can make something 10% more efficient, that's a game changing, industry conquering advantage.

Agree, but with a few caveats:

- The cost needs to be fairly easy to measure

- Some degree of competition in the industry exists (otherwise the capital could be used to increase revenue or acquire small potential rivals before they're too large to afford, among other higher return places to spend the capital)

- The industry is mature and sources of larger savings already exhausted

- Prospect for some future much bigger savings small (or at least not in conflict with the current effort)

- Prospect for the industry as a whole very good (in a shrinking market, 10% savings becomes lower priority than selling off assets quickly enough at high enough cost without subsidizing a competitor or startup)

- Industry consolidated enough (or capital costs of the improvement low enough) to finance the upfront cost

Re: Maersk installed 100-foot-tall rotating sails on one of its tankers

#73

Post by ant6n »

a_c_s wrote: post #45
joering2 wrote: post #19

What these ships are mostly surrounded by are waterfields that go as far as you can see. Can they come up with some sort of rolled flexible solar panels that once ship goes into full sail they release their “solar tail” behind that floats on the water surface and captures sun and turns it into electricity for ships’ engines? I mean 300 meters square of solar panel should be sufficient to push the ship at its nominal…

I think you're vastly overestimating the power output of solar cells. Using 20% efficiency panels gives us 0.2KW/m^2/hr. According to this Quora answer [1] a small container ship uses 15,000kW: for one 24 hour day that means it needs 360,000KWH in energy. If we assume 10 hours a day of full sunlight then we need 180,000m^2 (equivalent to 18 hectares or 44.48 acres or 33.7 football fields) of solar panels. This of cou…

I think you're under-estimating the power of the square. 180,000m^2 is 2 x 300m x 300m.

Re: Maersk installed 100-foot-tall rotating sails on one of its tankers

#74

Post by reaperducer »

ValleyOfTheMtns wrote: post #23

I've been wondering why shipping companies haven't been doing this for years now. Whenever I brought it up with friends they would say it's probably not worth the effort, but I can't see how it wouldn't be worth it. It's essentially free energy to help move the ship around. Got to say, I feel vindicated by this story.

Notice the height of the rotors. Cargo ships already have problems clearing bridges in some ports. I imagine that must also be a factor.

Re: Maersk installed 100-foot-tall rotating sails on one of its tankers

#75

Post by nabla9 »

Viking Line installed similar 80-foot rotor sail on a LNG powered Cruise Ferry on the route between Helsinki-Stockholm. It reduces power usage roughly 20 percent (900 tonnes CO2 annually). Compared to tankers ferries don't carry significant amount of weight even when they are full. They are basically full of air and 60-100 cars or trucks.

Together with using LNG, periodically cleaning the bottom of the ship, slower speed and connecting to electric grid while in harbor the CO2 emissions are down significantly.

The best way to reduce energy consumption for a ship is to reduce the speed and make thinner ships. This is the new trend in shipbuilding. New cargo ships optimized for slow speed don't have the bulbous bow because it does not increase efficiency in lower speeds.

Re: Maersk installed 100-foot-tall rotating sails on one of its tankers

#76

Post by delecti »

village-idiot wrote: post #22
IB885588 wrote: post #8

Another option is skysails (giant kites that drag the ship forward): https://en.wikipedia.org/wiki/SkySails Hopefully someday almost all ships have a mix of these things + maybe run on algae-based advanced biofuels or something like that.

Hydrogen fuel cells are looking likely. Solar will probably produce too much electricity for usage during the day, so use that spare energy to split water to create Hydrogen fuel.

I was curious how much sense this actually made so I did the math, sources at the bottom. I suspect my sources aren't perfect, but they're probably close enough to get an idea of things.

Our hypothetical container ship is roughly 400m x 59m, or 23600 m^2, and solar panels generate ~4.5 kWh/m^2 after inefficiencies, giving a total energy generated of 106.2 megawatt hours per day for a ship, if you had a big solar array above all the containers. Assuming an 85% efficient hydrogen fuel cell, that gives you losses both in storing and reclaiming electricity from that storage process. Assuming 1/3 of your energy can be used while generating it and the other 2/3 has to be stored as Hydrogen and then spent to power the energy, losing energy both ways, that leaves you an effective ~81 MWh/day.

Meanwhile the existing engines on that same container ship can currently run at about 90 MW, which means it can output more energy burning bunker fuel in one hour than our solar panels gave us in the entire day.

Container ship size: https://en.wikipedia.org/wiki/Container_ship#Size_categories Energy per day: https://www.quora.com/How-much-solar-energy-is-generated-per... Fuel cell efficiency: https://en.wikipedia.org/wiki/Fuel_cell Container ship energy usage: https://newatlas.com/shipping-pollution/11526/

Re: Maersk installed 100-foot-tall rotating sails on one of its tankers

#77

Post by jseutter »

jessewmc wrote: post #64
abtinf wrote: post #18

Some years ago I read The Box by Marc Levinson, a history of containerized shipping. Highly recommend it. If you live in SF and have wondered about the numerous barely used piers, this book explains their history as well - and why the major container terminal ended up in Oakland instead. One of the painful early lessons for the industry was the discovery that minimizing operational costs (particularly fuel and mainte…

Ignorant question: if operational costs trump all, especially fuel (Maersk says in the article 60% of operational cost) why not pure sail power? Is there some other maintenance cost or infeasability there? Or is there another hidden variable that is not satisfied?

This is a good question, and almost pure sail power may become a thing in the future. It looks like Maersk is trying to get ahead of the switch to cleaner fuel coming in 2020, which will increase their fuel costs by about 60%. This idea of putting sails on a large ship was at best only marginally cost-effective before now.

Some practical considerations come into play - while saving money is good, being able to reach your destination when you say you will is also worth something. With pure wind you lose that control. Deck size is not infinite, so there is a limit to how many sail towers are useful. Tower height also has practical limits before it destabilizes the ship. Handling bad weather is much easier with the on-demand power that comes from engines.

Re: Maersk installed 100-foot-tall rotating sails on one of its tankers

#78

Post by kevin_thibedeau »

dorfsmay wrote: post #28
fmsf wrote: post #2

It's called the Flettner rotor, it uses the Magnus Effect. Cool stuff but not exactly new tech. It gives a nice read, here's some links to wikipedia on the topic: https://en.wikipedia.org/wiki/Magnus_effect and https://en.wikipedia.org/wiki/Rotor_ship I'm curious of what will be the results.

> Cool stuff but not exactly new tech They explain that in the article, and the fact that it newer tech and lighter columns to get a net benefit. Having grown up in France, I knew about Cousteau's Alcyone (it was a big deal at the time) and had been wondering why it hadn't been used more since then.

Rotor ships predate the turbosail.

Re: Maersk installed 100-foot-tall rotating sails on one of its tankers

#79

Post by hinkley »

DannyB2 wrote: post #27

From TFA... > Maersk Line spent around $3.4 billion on fuel last year for its fleet of around 800 vessels. Wouldn't savings from wind power be bad for the petroleum industry? And therefore by lobbyist extension bad for everyone?

Reducing operating costs often leads to higher overall demand.

Re: Maersk installed 100-foot-tall rotating sails on one of its tankers

#80

Post by DannyB2 »

macmac wrote: post #38
DannyB2 wrote: post #27

From TFA... > Maersk Line spent around $3.4 billion on fuel last year for its fleet of around 800 vessels. Wouldn't savings from wind power be bad for the petroleum industry? And therefore by lobbyist extension bad for everyone?

That's Maersk Line, which is the container shipping division of Maersk. The rotor sails are being installed on a tanker vessel from Maersk Tankers. Deck space is a valuable commodity on a container vessel, so not as obvious where to place the rotors.

I quoted that line exactly from TFA. (the friendly article)
Post reply on HN