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Comment by Broken_Hippo | Hacker News Reader

I've hit my limit for the economist this month, so I went and looked up the article. It seems these articles have been coming out since at least 2009, and the gist is that because these (older) ships burn heavy fuel, which isn't refined like gasoline.

And it seems the fix is to urge the companies to update their ships by not allowing them in ports, but considering how long these articles have been coming out, it looks like progress is slow on that front - and if it has changed. Shipping companies have been selling off some of their stock, and it would seem that at least a few of the older ships should have been included.

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It's more so that they have no scrubbers on them at all than the specific kind of fuel they burn. A random ten-year-old diesel truck has a way better pollution control system on it (by virtue of it even existing) than the largest cargo ships in the world, despite burning way, way less fuel. It just comes down to cost and lack of pollution emission regulation at a global level, which should absolutely be addressed.

Is retrofit possible?

Technologically or economically?

Unless something is outright technologically impossible, it's awfully hard to separate those things.

Is it feasible is the real question.

Yes, it is. You add huge stacks of scrubbers to the exhaust system. It's not any different than scrubbing the exhaust of a truck's diesel engine in principle, just on a much larger scale. Of course, it is still quite expensive, so shipping companies won't install them until they're mandated. We're talking retrofits costing many millions of dollars per ship.

It is in fact largely the specific fuel that they burn. "Heavy fuel oil" is where the refineries direct almost all the sulfur and heavy metals originally present in the crude. The sulfur content of HFO can be, and often is, up to 3%.... cf auto diesel in the example 10 yo truck where a maximum of 10 ppm is permitted.

Incidentally, the kind of pollution control measures that are used on truck engines, eg cat converters, are unable to cope with the contaminants present in HFO. The catalyst becomes rapidly poisoned and ineffective. So a retrofit to conform with automotive standards is unfortunately not possible.

Thanks for the info. So if it's largely a refining problem, is anything lost if bunker fuel is simply outlawed? (Besides lower cost anyway?) Is bunker fuel an inescapable result/byproduct of petroleum refining, or can it be refined further into less-polluting, more desirable fuels?

It's complicated... crude oil is a mix of hydrocarbons with carbon chain lengths between say 5 and 40+, plus various impurities such as sulfur. It is refined into gasoline (~7-12 carbon atoms per molecule), diesel (~12-18) etc, with bunker fuel containing the heaviest fractions. It is possible to crack the heavy fractions into lighter ones, and this is commonly done at most refineries.

However, what to do with the impurities? You can take them out, but then disposal becomes a problem (see image below for example). So, if possible, refiners tend to leave them in the product.

http://www.petroleumjournal.kz/imgdb/article_3/article_3_pre...

That yellow stuff is elemental sulfur.

For at least 15 years in Norway I have read articles urging local ship companies to switch to greaner engines running on liquid gas or even electricity. The progress has been made as occasionally I board an electrical ferry without unpleasant smell coming from the pipes. But it is very slow.

And this is not surprising as ships are designed to run for 50 years or more and engine upgrades are very costly.

Newer ships aren't necessarily much better. Mærsk's E class container ships still burn bunker fuel. The Triple E Class made improvements in efficiency and emissions, but are still burning bunker fuel at about 50% of the emissions per container than the previous class.

From what I understand, these ships are huge and cover very large distances. This requires a lot of fuel. Bunker is the cheapest fuel for this use-case (it, -- sort of literally -- being a bottom of the barrel sort of thing).

Not sure what the global impact would be of banning bunker, or (trying to) refine it. Economic or environmental.

With the disclaimer that I have no idea what I'm doing and there are probably many flaws in this reasoning:

A metric ton of bunker is about $300 (http://shipandbunker.com/prices)

The same volume of diesel would be about 315 gallons and would be about (https://www.extension.iastate.edu/agdm/wholefarm/html/c6-87.... / http://www.indexmundi.com/commodities/?commodity=diesel), so about $500.

The energy density of the diesel is about 13% higher than the bunker (https://people.hofstra.edu/geotrans/eng/ch8en/conc8en/energy...).

Assuming identical efficiency (no clue on this point), you would end up paying about 50% more for the same amount of "energy." We would also be dramatically increasing the worldwide demand for diesel and we'd still have the leftover residual product from refining that was previously used to fuel these ships.

50%+ margin increase on containerized shipping seems pretty significant.

I had a job years ago that involved software and (small) vendor-provided gear for ships and getting this stuff out deployed to vessels was a slow and painful logistical nightmare. 'Update your ships' sounds about a million times worse so we'll probably be reading more of these articles for a while.

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