Michelin Puts Puffy Sails on Cargo Ships
spectrum.ieee.org
spectrum.ieee.org
It's an interesting concept but I can't really see how it scales to large ships. To propel a larger ship you need a huge amount of force which requires a very sturdy mast and stays (guys) which support the mast. Without those elements the amount of force that can be transmitted will be negligible.
https://www.nytimes.com/2021/06/24/magazine/cargo-ships-emis...
One question I have is, how would this work with a sort of semi-circle fan version, where the blades retract when they start getting pushed into the wind. This could theoretically have the rotor turn off of just wind power instead of external power. Here's a crude drawing lol [2].
As regard stays, the stay needs to be at 90deg to the sail orientation. Presumably mounted on some kind of circular track to rotate with the sail.
The engineering is challenging but not inconceivable.
Did we read the same article? I read that the system was completely autonomous at the press of a button and automatically retracted in bad weather and for bridges
That's Hacker News at its finest.
more of how an airplane wing generates lift (bernoulli's principle) then catching wind.
Look at Maltese Falcon rotating mast. They don't have any shrouds, although they are carbon fiber made.
The reason here is the extremely low cost of energy from photovoltaics: We see less than $0.03 per kwh [projected prices for some currently planned large scale farms] - that's about $0.3 for the energy of 1 kg of bunker oil. Bunker oil sells for about $300 to $500 per ton, so roughly $0.4 per kg. That means that a replacement fuel with more than 66% conversion efficiency could already be competitive right now. High Temperatur Hydrogen Electrolysis is reportedly available with 80% energy efficiency. As far as I know, there is no indication that solar costs could stop falling anytime soon, so in the next 20 years we will probably see it drop well below $0.01. So if I did not misplace a decimal somewhere, the future should be in relatively cheap large-scale green fuel.
I know Keto and Atkins are popular but I’m not sure the world as a whole will move off carbs… :-)
Besides, although it's a possibility that we will have abundant solar within 20 years, let's also build on the basis that we might not and solve the problem from multiple angles!
For example, it saves 20% of your fuel cost, great! But its cost is 10% of your fuel cost. At current fuel prices, you still come out ahead, since you are saving more than you are paying.
However, if fuel is 1/4 the cost of now, then you still save 20% of fuel cost, but the sails now cost 40% of your fuel cost… aka the sails now cost you money to run.
To be clear, while these sails are profitable, they will be used. Op is just saying that they think they will become unprofitable sooner than expected.
Green fuels will need to ramp up their production to meet the demand, better actual efficiency (not just financial) means that ramp up wouldn't need to be as steep as the demand won't be as high so we will have an easier time actually filling that demand.
It's a bit like not changing to more energy efficient light-bulbs based on the assumption that in 20 years green fuels will make electricity so affordable, and emissions neutral, that it allegedly won't matter.
One could do that, but if the cheap green energy doesn't end up materializing in that time then you did nothing to reduce to problem and end even further removed from an actual solution.
Even if it takes them a year to equip all their fleets with these sails, they'd still be saving money and fuel for the time until they're not needed anymore.
Until then--they will do stunts like this in order to show they care. (20% savings in fuel is big though. "Stunt might be to cynical?)
I feel the companies that use shipping are scared. They are afraid of tariffs/taxes tacked on to their cheaply made products if the public starts complaining.
They got away with manufacturing in the cheapest country. We just gave up trying to buy reasonably priced products at home.
I imagine they are very scared of their perceived culpability in Global Warming though?
I am all for the sails. They don't seem copacetic with container ships though?
The filthy loucres couldn't carry as many containers with sails?
That said, ships aren’t limited to container ships. Oil tankers have a lot of available deck space.
You mean hydrocarbons?
Dunno, as with all of these things we have to look at the lifecycle; how long is a ship in service? How many are being built with non-hydrocarbon fuels, or converted, today? It's a very small number. Mostly short-haul ferries on government-influenced routes e.g. https://www.cruiseandferry.net/articles/scotland-explores-fe...
Energy extraction from oil is typically a low efficiency cycle. ICEs are around 30% efficient. Gas Plants are around 40% efficient.
Energy from solar -> batteries -> application usually hovers around 70 - 80% efficiency.
Motors are around 98% efficient. That covers most of our requirements for manufacturing. Conversion of electricity to heat is almost 96-98% efficient.
Large marine diesel engines can have a thermal efficiency > 50%.
Nope, energy from solar is around 20%, batteries are at around 90% efficiency.
Exactly where these auxiliary sail systems are of no use. The only way to address this is short range electric power for use in harbors.
To deal with ports not wanting them to come in, you can use ocean-faring nuclear powered tugs that hand-off long-haul cargo barges to electric or fossil tugs for the final 10 km.
This was tried in the 1960s (see N.S. Savannah [1], Otto Hahn, etc.). Russia actually operates a nuclear powered cargo ship today (Sevmorput), though it does cause problems e.g. when the propeller breaks on the way to Antarctica and no shipyard will let you in [2].
The key is to mass produce them in such a way that economies of mass production can be used to alleviate the challenges of nuclear costs. Interestingly, this also parallels with options to help decarbonize the world with shipyard-constructed offshore nuclear power stations [3].
[1] https://en.wikipedia.org/wiki/NS_Savannah
[2] https://thebarentsobserver.com/en/nuclear-safety/2020/11/mec...
[3] https://whatisnuclear.com/blog/2020-01-26-offshore-power-sys... (disclaimer: my site)
The mobile security force isn't going to be authorized to start a war
[0] https://maersktankers.com/newsroom/norsepower-rotor-sails-co...
I don't know much of ships and their fuel consumption, but I would guess that any percentage point of fuel saving would quickly add up to a significant cost reduction
especially if the ship is loaded with materials.
Ugh. A sail, most of the time, is a wing.
https://en.wikipedia.org/wiki/DynaRig
The fancy sailing yacht Maltese Falcon, commissioned by the deceased billionaire VC Tom Perkins (of Kleiner Perkins fame), was built with that design:
https://en.wikipedia.org/wiki/Maltese_Falcon_(yacht)
Here is a book on the boat:
https://www.amazon.com/Mines-Bigger-Extraordinary-Greatest-S...
The only questions I would have are:
- Do the sails automatically retract for height clearance?
- What is the cost of installation (how many years to repay initial costs)
- What are the ongoing maintenance costs?
- Is the 20% the average cost savings per trip, or only while the sails are in use?
Outside of that, this seems like an obvious solution for retro-fitting any tanker-type vessel. Cargo container ships may not be able to fit something like this.
Still, 20% savings and that is regardless of the fuel used I'd imagine. It's just on top of whatever normally is powering the ship in conditions that would support the automatic deployment of the sails. I'd imagine this is best on certain routes that generally have stronger winds.
It seems that system automatically deflates and tucks itself away for bridges or if sea becomes rough.
My understanding is that cargo ships usually operate on rather thin margins except during a occasional fat times (like right now)... If new sail designs were actually economically beneficial, ship owners would adopt them ASAP. As the quip goes, they like money. Color me cynical, but I don't really think they care too much about the environment.
You'd be surprised.
Large ship engines can be on the order of 10,000-30,000 hp or more. In KW that's 7.5-22MW.
A large cargo ship might be Panamax (https://en.wikipedia.org/wiki/Panamax) and thus 950ft long and 105ft wide or have a total top surface area of 99750 sqft. Commercially available solar panels have an efficiency of around 20% and sunlight is often quoted as 100w/sqft so you might be able to generate 2MW of electricity from covering the entire top of the ship in solar panels. 2MW compared with say 15MW is significant but there are problems.
That's for a flat array, not something that tilts. So you're only going to get about 6hrs of full power output per day, assuming good weather. Now your 2MW drops to only 500kW of average power or lower.
And those panels are going to cost at least $0.50/watt or something like a million dollars, nevermind mounting, inverters, cabling, etc. Could easily triple the price there. Plus the sea is rough on everything. If the panels are rated for 30 years on land you should expect to get less than 10 years at sea, maybe less.
Finally the assumption that you can simply cover the top of a ship with no repercussions isn't necessarily true. For tankers and bulk carriers you might get away with it. But on container ships you'd have to figure out how to make the entire array fold away since these ships are top loaded and unloaded. https://thumbs.dreamstime.com/z/container-cargo-cranes-unloa...
The idea makes sense if you don't know the magnitudes of things. But once you do it starts to look less practical.
and then there is this https://en.m.wikipedia.org/wiki/Blackbird_(land_yacht)#:~:te...
Also I know there were some experiments with electrostatic or bubbles on the hulls of these huge ships... https://www.google.com/amp/s/www.marineinsight.com/green-shi...
Also what about huge autonomous kites...? https://en.m.wikipedia.org/wiki/SkySails I mean surely such systems are complicated but with today's sensors and autonomous systems i'm sure people could come up with something that is better than burning 3rd grade fuel to bring us gadgets and junkets...
Also, as oil is consumed, the ship gets lighter and easier to push. Not so with batteries.
Making it more efficient is the only way forward.
I wonder if maybe there are good options for powering electric ships mid-journey. For instance, suppose you have a container ship with enough battery capacity to operate for one day. On its usual route, there is a power line running along the ocean floor, and buoys at regular intervals with cables that bring the power up to the surface. Once a day, the ship stops at one of these buoys and charges its batteries for an hour, then continues on its way.
I still don't think using traditional sails is practical though, and kites are a far more elegant and useful solution. They require far less cost and are easier to retrofit onto existing hulls, can be easily scaled up or down depending on wind conditions, and in the event of even catastrophic failure are pretty safe (i.e. if the kite line were to break). The biggest danger of them is the kite line falling in the water and getting fouled on the propellers, but this is a solvable problem.
Sailing boats with a keel usually resist capsizing because as they heel over the keel is pushed to windward at a greater angle, increasing the righting force it provides to the hull. Additionally the greater angle of heel decreases the area of sail that’s being exposed to the wind, further increasing the overall effect of the righting force. It would be interesting to see how these can be retrofitted to an ordinary cargo ship though, sailing boats are optimised for a particular amount of heel whereas as far as I’m aware cargo ships generally aim to avoid heel altogether as far as possible with large ballast tanks where water is pumped around.
By adding so much surface area so high up you create a lever for winds to create torque to cape size the vessel.
The way sailing boats circumvent this issue is by having a big long metallic fin at the bottom of the boat(called keel). The keel counteracts the torque of the wind when the boat rotates and brings it back to a steady position.
The problem is that ports have fixed depth so if you modify an existing cargo ship with a keel it will no longer fit into the commercial ports