Fuel economy of the world's longest in-service ship

The Emma Maersk is the second longest ship in the world, and the longest currently in service. It's so large, it looks photoshopped into any picture it appears. Driving such a large ship requires a lot of power. From Wikipedia:

The Emma Maersk is powered by a Wartsila-Sulzer 14RTFLEX96-C engine, currently the world's largest single diesel unit, weighing 2,300 tons and capable of 109,000 horsepower (82 MW). The ship has several features to protect the environment. This includes recycling the exhaust, mixed with fresh air, back into the engine for reuse. This not only increases efficiency by as much as 12% but also reduces engine emissions. Instead of biocides, used by much of the industry to keep barnacles off of the hull, a special silicone-based paint is used. This increases the ship's efficiency by reducing drag while also protecting the ocean from biocides that may leak. The silicone paint covering the part of the hull below the waterline is credited for lowering the water drag enough to save 1200 tons of fuel per year.

We started talking about energy consumption after watching a practice version of Saul's upcoming E-Tech Keynote, Energy Literacy, and Dave Culp of Kiteship and Speed Sailing did a back-of-the-envelope MPG calculation for this ship:

A few more facts about Emma Maersk:

Running at her rated 80 Mw, her main engines burn 14 tons of residual fuel each hour. Annually, that's 97,400 tons of fuel. Her auxiliaries, delivering their full 30 Mw, burn an additional 6.6 tons/hour, for a total fuel burn of 20.6 tons/hour. Given 290 steaming days/year (80% capacity factor, which is conservative), this yields a total annual usage of 143,400 tons or about $64.5 million in annual fuel costs.

Burning 20.6 tons/hour = 6724 gals/hour. At 31 kts/hour, this equals .0046 nautical miles/gallon. At 6076 ft/nautical mile, that's 28 feet/gallon of fuel burned.

The 1200 tons saved by her "revolutionary" bottom paint represents a bit less than 1% of this cost, so increases her fuel mileage to 28.2 feet/gallon.

Dave concludes:

You gotta haul a lot of containers full of $7 tee shirts to make this profitable.

28 feet/gallon!

Images from jtashipphoto.dk and Wikipedia.

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neffk6 years ago
This isn't really an instructable.  Don't you have a blag where you can post stuff like this?  Or maybe you should add it to Wikipedia.  It's interesting and all, but not the kind of thing I expect on this site.
ilpug neffk3 months ago

So this is a dead topic, but the OP is actually the guy who started Instructables, I found this a bit entertaining

lemonie neffk6 years ago
No, it's a Forum Topic, i.e. "a blag" and in the right place. (It's also >2 years old).

neffk lemonie6 years ago
lemonie neffk6 years ago
I find it interesting though, so I was pleased you "bumped" it.

Terah'sP1 year ago

correction* 320k tonne is of course 320000000 (320 million) kilo.

Terah'sP1 year ago

Necroposting ftw! (still, the ship's still around in 2015 after a 45 million USD repair in 2013, so who knows who may read this in the future :))

Right, on with it!

The Emma Maersk captain will typically aim to have her run as energy efficient as possible, which averages around 1700 gallon/hour, or roughly 6 tonnes/hour.

Using a price of 450 USD per tonne of marine diesel, this reduces the yearly fuel consumption to around 20 million USD (I added a few million just in case they need to fire the auxiliaries more often).

With the 1200 tonnes of fuel saving due to the silicone based paint, adding up to around 540k USD, the savings are more likely to be in the neighbourhood of 2.7%.

While this still sounds like a drop of water on a hot plate, 540k is still 540k that we, the consumers, don't have to cough up for our products.

As for the question if adding sails would make it more fuel efficiency:

Like geeklord mentioned, burning things is easy. We already have technologies in place to provide us with fossil fuels that are known to have enough oompf to bring a ship with a total weight (own weight + cargo) of around 320k tonne (320000 kilo) into motion and keep it going at a certain speed.

For sails to take care of some of that speed, considering the size that the sails would have to be, the masts that would be needed to hold those sails up, the times per week/month/year those sails could actually be deployed, I am pretty sure that the added weight and costs, set off against the fuel savings during the times the sails would actually be used (which is only between certain min and max windspeeds), adding sails would add to operational costs of the ship while doing very little to actually make the investment worthwhile, and I doubt that any such investment would pay itself off during the lifetime of the ship.

geeklord7 years ago
If this makes any sense at all, what is the potential energy of a galon of gasoline in watts(or another sort of measurement,joules?).
good question---as you say, the energy is measured in joules not in watts, which are a unit of power (energy per unit time). A typical figure quoted around
is 115000 btu/gal which is 121 MJ/gal. Diesel has slightly higher energy content,
maybe 125-130 kbtu/gal.

To put this in perspective, even the best batteries have pitiful mass and volumetric energy densities, which is why electric cars are so handicapped now. We need
big energy developments before the electric cars will be really competitive.

Funny, I just finished Science 9 in school (with a 99% percent, thank you very much), and I learned all about joules, watts, Newtons, etc. That's a lot of energy. I now see why burning things is so easy.
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