How Green Is Maersk's Bio-Methanol Fuel?

Agricultural waste and green hydrogen turn into fuel that could change shipping.

Maersk Container ship

Niels Wenstedt/BSR Agency/Getty Images

In a recent post by Treehugger's Sami Grover about shipping companies taking baby steps into zero emissions future, he noted that the world's largest shipping company, Maersk, had ordered eight ships capable of running on bio-methanol. But he qualified it by noting, "Exactly where Maersk is going to source its bio-methanol, and whether those sources can scale to meet a significant portion of global shipping needs, could make all the difference between this being a symbolic move of limited value and a serious step toward lower emissions shipping."

Maersk is getting its bio-methanol from REintegrate, a Danish company that is making "clean and energy-efficient e-methanol chemically identical to fossil methanol, making the transition to green seamless for transport and chemical sectors."

Methanol is traditionally made by producing syngas, a synthetic natural gas, by reacting hydrogen with carbon dioxide. This is then put through a reactor with the ultimate chemical reaction being:

CO + 2 H2 -> CH3OH

REintegrate plans to recycle CO2 emissions, react them with green hydrogen made with renewable electricity, with the by-products heat and oxygen used in industry or for district heating. In response to the important question of where the CO2 is coming from, Maersk told Treehugger:

"Biogenic CO2 is coming from agricultural waste products in the surrounding community—meaning that the CO2 would have been let out into the atmosphere had we not taken it and processed it into e-methanol."

Well, yes, that's true; if agricultural waste is just left to rot, then the CO2 goes into the atmosphere. As energy expert Paul Martin told Treehugger, "It is a shell game unless the CO2 came from biological sources, i.e. it was recently CO2 in the atmosphere."

Biogenic CO2 is controversial, because a biogenic molecule of CO2 is identical to a fossil molecule. However, the International Energy Agency explains:

"Burning fossil fuels releases carbon that has been locked up in the ground for millions of years, while burning biomass emits carbon that is part of the biogenic carbon cycle. In other words, fossil fuel use increases the total amount of carbon in the biosphere-atmosphere system, while bioenergy systems operate within this system; biomass combustion simply returns to the atmosphere the carbon that was absorbed as the plants grew.

Many complain that this just encourages the harvesting of trees that could have stored the CO2 for many more years and instead are turned into pellets and burned now, but that is not the case if they are burning agricultural waste.

Others believe it is still a shell game, just moving CO2 around. When you burn the biomass and collect the CO2 and turn it into methanol, all the CO2 is released when the fuel is burned. Lasse Kristoffersen, chief executive of Norway’s Torvald Klaveness, and a fan of using hydrogen directly as fuel, is quoted in the Financial Times, asking, “Why on earth should we release CO2 into fuels when we have captured it in the first place?”

bio-methanol production

Methanol Institute

It should also be noted that methanol can be made from biomass directly through fermentation, producing biomethane which is then put through that reactor to make methanol. This is actually pretty common. Paul Martin wonders why they haven't gone that route if they have biomass: "Then it's just a massive waste of energy relative to making methanol FROM biomass by gasification, perhaps augmented a bit with green hydrogen."

ThyssenKrupp methanol Production
Capturing CO2 from steel production.

ThyssenKrupp via Methanol Institute

The answer to that question is probably that, while Maersk says the CO2 is coming from biowaste, the REintegrate process can take CO2 from anywhere. German steelmaker ThyssenKrupp is proposing making methanol through the same process from their own CO2, gathered after making steel. You don't need to go out and burn waste to get CO2; there is enough of it to go around.

So it's not really a shell game. Instead of burning fossil fuels and emitting CO2 directly, the Maersk process is gathering CO2 that would have been released anyway, converting it to fuel and releasing it later. They are using biogenic CO2 in the process now, which makes the whole process carbon negative, but if it eventually sucks up CO2 from industrial processes because there is not enough agricultural waste, that's not such a terrible thing.

It might actually one day be a good thing. Currently, the e-methanol is estimated to cost about twice as much as bunker fuel, but if you have a carbon tax that affects both that steel mill and the shipping line, that gap might close fairly quickly.

Maersk CEO Soren Skou says, “The time to act is now if we are to solve shipping’s climate challenge.” Using e-methanol is a great place to start.