The global industry is responsible for about 3.1% of global CO2 emissions, and that number goes up when you consider black carbon emissions, as the soot and unburned hydrocarbons have a 20-year global warming potential (GWP) of 4,470, and a 100-year GWP of 1,055–2,240. Yes, our Amazon purchases and salads come with a carbon debt.

So what is Maersk doing? It has ordered 8 post-Panamax container ships able to carry 15,000 containers each from South Korea’s Hyundai Heavy Industries, with delivery scheduled for 2024. The ships will be able to burn methanol or bunker fuel in their engines. The methanol is supposed to be carbon-neutral.

However, Maersk runs over 700 ships, so the 8 ships powered by methanol drive trains represent about 1% of its fleet. Not exactly getting rid of bunker fuel rapidly.

Methanol is interesting as a fuel choice. It’s made from natural gas via one of the steam reformation processes, similar to hydrogen in that regard. About a ton of CO2 is produced for every ton of methanol that’s produced, and right now 0% of that is captured. When a ton of methanol is burned, another 0.6 tons of CO2 is emitted. Maersk’s press release talks about carbon-neutral methanol, which suggests using flue carbon capture and follow-on sequestration of the CO2 produced in the steam reformation process.

Bubble diagram of scale of CO2 problem versus capture and use by author

As I’ve published extensively on global carbon capture and sequestration schemes, I’m confident in saying that approaching 0% of CO2 from methanol manufacturing from natural gas and burning as a fuel will be captured, used, and sequestered in the future.

The energy density of methanol is interesting too. The energy density of bunker fuels is about the same as the diesel cited in the linked source. Methanol requires a lot more space and weight on a ship for the same kilometers traveled than traditional fuels.

Running at the cruising speed of 20–25 knots, a Panamax container ship will use about 63,000 gallons of marine fuel every single day. Assuming US gallons (they are smaller, so this is the conservative choice), that’s about 240 tons of fuel a day with diesel or bunker oil. Freighter ships average 40–50 days of travel, although some of that is at lower speeds where fuel consumption drops dramatically. Assuming 40 days, that’s close to 10,000 tons of fuel.

For methanol, basically double that to 20,000 tons of fuel, and comparably less cargo space. Methanol from natural gas with no carbon capture costs over double what bunker fuel does too, over $1 per gallon compared to around $0.50 per gallon.

That means that the same journey will cost 4 times as much in fuel costs, and emit a bunch of CO2 as well.

What methanol does provide is a cleaner-burning fuel. Bunker fuel is nasty stuff, and ships typically get the cheapest, lowest grade, barely refined crap that they can buy. Black carbon — soot and unburned hydrocarbons — is a major pollutant and has an enormous global warming potential as noted above. Vastly less black carbon from methanol than bunker fuel. Ditto sulfur, which is another noxious substance from ships with acid rain implications. Finally, there is high global warming potential nitrous oxide, which is much lower than with bunker fuel.

Right now ships have scrubbers that capture a bunch of the sulfur, particulates, and nitrous oxide, at least when they are operating. Having spoken to an engineer who designs, builds, and installs them on ships, a big focus is on getting the smokestack emissions to look white, like water vapor. The appearance of cleanliness, if not actual cleanliness.

CO2 still gets emitted, however. The CO2 per unit of methanol burned is about 40% of bunker fuel, however, since you need to burn twice as much of it to get the same energy, it’s about 80% of emissions. This isn’t a CO2 saving that’s worth writing home about if the methanol is made from natural gas. It’s more of a value proposition if the CO2 is captured from flue gas or the air or vegetation, but that leads to the very high cost of “green,” synthetic methanol.

It’s possible to manufacture methanol that’s green-ish. You could capture CO2 from somewhere, crack water with electricity to create the hydrogen, and then merge them into methanol. I went deep on this a couple of years ago when looking at Carbon Engineering, a direct air capture fig leaf for various fossil fuel companies.

Table of green methanol manufacturing by author

That turns out to be close to $3 per gallon solely for manufacturing cost in the best case scenario, compared to the just over $1 for natural gas-sourced methanol. Instead of 4x costs for a journey for fuel, it would be 12x costs.

Let’s put this in perspective. Today with the cheapest bunker fuel that you can get, fuel costs represent 50% to 60% of operational costs. Methanol from natural gas without carbon capture makes that about 80%. Methanol from natural gas with carbon capture would make it approach 90%. Green methanol makes it well over 90%.

So will the shipping world sit up and take notice of Maersk buying 8 methanol powered ships? Yes, they will. They know the math and economics much better than I do, as they live it every day. They know that the 8 ships represent a fig leaf for Maersk. They will note that the ships are dual fuel, able to run on methanol or on bunker fuel, and will know that outside of demonstration runs, Maersk will operate them entirely on bunker fuel for the vast majority of their service life.

They will likely be glad that Maersk is doing PR for the global shipping industry. And there won’t be a big lineup for South Korea’s Hyundai Heavy Industries services to build more of them at 10–15% markups on normal ship construction costs.

Long-haul shipping remains a hard problem for decarbonization. Maersk’s purchase isn’t going to address it. The roughly $150 million extra that it paid for the 8 ships is about 0.4% of Maersk’s annual revenues, or about 1.5% of its expected 2021 profits. This is in the range of expenditures by fossil fuel majors on carbon capture, which is to say PR fig leaf territory, and the ships will undoubtedly run on bunker fuel, not methanol, for the vast majority of their freight miles.

Featured image credit: Maersk

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