Marine shipping is usually categorized in the hard-to-decarbonize segment of transportation. But that’s not really true. The actual requirements for burnable fuel replacement are a lot lower than most realize or accept, and there are many solutions in the space. And, of course, there’s a lot of boring stuff that just works.
This is the third in a series of quadrant charts positioning purported and actual climate action solutions against hype and pragmatic quadrants. The first two in the series covered electricity and energy storage, and ground transportation.
Let’s start with the sexy stuff that actually will move the needle on decarbonization in marine transportation. And when it comes to sexy, maybe it’s just me, but things like the X-Bow, the torpedo-like waterline bulbous bow, and other hull innovations including massive scaling up get me interested. Despite the earliest water craft appearing thousands of years ago, there’s still room for very interesting and performance-enhancing hull shapes for different applications. The hull size one is amazing because the fuel requirements per ton drop as ships get bigger, and it’s not about how much fuel the ship uses, its how much CO2 per ton of cargo is emitted. And that’s even before innuendos about big hulls entering long canals.
The next one that’s mostly in the quadrant is parafoils. Autonomously launching and furling systems exist, are easy to retrofit and work with minimal to no crew intervention. A few firms and ships have been using these for a decade, and getting good results. Skysails couldn’t make it a profitable business line despite it being useful, and so have devolved to solely being a not useful airborne wind energy company. However, others continue to work on it. The primary challenge with all marine innovations is the same disconnect in efficiency solutions for commercial buildings, in that the owners and users are typically not the same firms, and operational costs adhere to the leaser, not the owner or builder. I suspect the market will find a way to square this circle and autonomous launching and furling parasail technologies will assist ships to save fuel in the coming decades.
Moving into the sexy but impractical quadrant, the top row shows a clear trend, and indeed the trend extends across most of the versions of these quadrant charts. Hydrogen is not fit for purpose as a marine fuel. It’s ineffective, inefficient, and expensive. Its low volumetric energy density would displace vast amounts of cargo to little avail. It boils off. And, of course, the massive infrastructure required to deliver hydrogen to ships during bunkering doesn’t and won’t exist outside of failed experiments. There are a couple of prototypes plying the waters of the world, but they are a rounding error compared to the actual transformation that’s occurring.
Similarly, shipping hydrogen by water makes little sense. In addition to the much greater cost of the hydrogen, there’s the much greater energetic cost of liquifying the hydrogen, the lower volumetric energy density of the resultant liquid than energy carriers like LNG, and the excessive boil-off due to 24° Kelvin temperatures. What does make sense is HVDC transporting electricity with very low losses thousands of kilometers as necessary, and manufacturing hydrogen at point of industrial use.
Hydrogen demand projection through 2100, with little transportation use, reducing demand for fertilizer and refineries, and the like” data-image-caption=”Hydrogen demand projection through 2100 by author” data-medium-file=”https://cleantechnica.com/files/2022/05/Hydrogen-Demand-Projection-400×225.png” data-large-file=”https://cleantechnica.com/files/2022/05/Hydrogen-Demand-Projection-800×450.png” loading=”lazy” class=”size-full wp-image-265940″ src=”https://cleantechnica.com/files/2022/05/Hydrogen-Demand-Projection.png” alt=”Hydrogen demand projection through 2100″ width=”1920″ height=”1080″ srcset=”https://cleantechnica.com/files/2022/05/Hydrogen-Demand-Projection.png 1920w, https://cleantechnica.com/files/2022/05/Hydrogen-Demand-Projection-400×225.png 400w, https://cleantechnica.com/files/2022/05/Hydrogen-Demand-Projection-800×450.png 800w, https://cleantechnica.com/files/2022/05/Hydrogen-Demand-Projection-768×432.png 768w, https://cleantechnica.com/files/2022/05/Hydrogen-Demand-Projection-1536×864.png 1536w, https://cleantechnica.com/files/2022/05/Hydrogen-Demand-Projection-1024×576.png 1024w, https://cleantechnica.com/files/2022/05/Hydrogen-Demand-Projection-600×337.png 600w” sizes=”(max-width: 1920px) 100vw, 1920px”/>
Hydrogen demand projection through 2100 by author
As much as the fossil fuel industry, governments in their pockets, and advocates want to think otherwise, hydrogen is a major climate problem on the scale of all of aviation right now, and that must be addressed before we start trying to invent new markets for it. It’s a climate problem, not a climate solution, and major demand areas must diminish radically if we are to solve climate change.
Synthetic fuels both extend some of the problems of hydrogen, but also alleviate others. Manufacturing synthetic fuels requires first getting CO2 and hydrogen at great energetic expense from flues/air and water. Then more energy is required to combine them to manufacture precursor hydrocarbons, and then typically they have to be upgraded to usefully dense fuels suitable for bunkering. Many firms such as Carbon Engineering are making extravagant claims about plug-compatible synthetic fuels, but the numbers simply do not add up.
Next we get to some sexy purported solutions that are sleek and romantic and are completely dead in the water. Let’s start with sails. There have been a bunch of efforts to put sails, whether hard foils or Magnus-effect rotors, on cargo ships. They all fail the most basic of logical tests, which is whether they will detract from cargo space or not. Marine shipping is cargo containers stacked high above the deck precluding sales, a growing segment, and bulk carriers, 40% of which are carrying coal, oil, and gas and hence in decline, and another 15% of which are carrying raw iron ore which is likely to be processed much closer to home.
Global Shipping in Megatonnes of Freight aggregated and normalized from multiple sources to create a unified perspective” data-image-caption=”Global Shipping in Megatonnes of Freight by author” data-medium-file=”https://cleantechnica.com/files/2022/04/Global-Shipping-in-Megatonnes-of-Freight-400×225.png” data-large-file=”https://cleantechnica.com/files/2022/04/Global-Shipping-in-Megatonnes-of-Freight-800×450.png” loading=”lazy” class=”size-full wp-image-263251″ src=”https://cleantechnica.com/files/2022/04/Global-Shipping-in-Megatonnes-of-Freight.png” alt=”Global Shipping in Megatonnes of Freight” width=”1920″ height=”1080″ srcset=”https://cleantechnica.com/files/2022/04/Global-Shipping-in-Megatonnes-of-Freight.png 1920w, https://cleantechnica.com/files/2022/04/Global-Shipping-in-Megatonnes-of-Freight-400×225.png 400w, https://cleantechnica.com/files/2022/04/Global-Shipping-in-Megatonnes-of-Freight-800×450.png 800w, https://cleantechnica.com/files/2022/04/Global-Shipping-in-Megatonnes-of-Freight-768×432.png 768w, https://cleantechnica.com/files/2022/04/Global-Shipping-in-Megatonnes-of-Freight-1536×864.png 1536w, https://cleantechnica.com/files/2022/04/Global-Shipping-in-Megatonnes-of-Freight-1024×576.png 1024w, https://cleantechnica.com/files/2022/04/Global-Shipping-in-Megatonnes-of-Freight-600×337.png 600w” sizes=”(max-width: 1920px) 100vw, 1920px”/>
Global Shipping in Megatonnes of Freight by author
Only bulk carriers might possibly have sails on the deck, and that’s deeply unlikely. A parasail assist on the bow is well aligned with forces through the frame and requires no major hull structural adjustments, but full scale sails would interfere with loading and unloading and require completely new hulls.
Next, let’s talk about hydrofoils. I love them. I really do. I want to ride a hydrofoil electric surf board. I had hoped to become a good enough kitesurfer to hydrofoil. If I ever get a chance to ride around in a hydrofoil boat, I’ll leap at the chance. But they are a niche technology that’s fragile. They’ve been around for a long time, and they haven’t taken over any market.
To be clear, I just finished re-reading Paolo Bacigalupi’s Ship Breaker pair of books, and enjoyed them (although they aren’t as good or resonant as his novel Water Knife). They feature hydrofoiling freight sailing ships with jet stream parasails (another nonsense idea) as a key component, and they were deeply evocative, even if deeply silly from any pragmatic perspective. As a lifelong wind sports guy, I would really like to believe in the return of sailing ships, but sadly I know better. I’ll have to make do with parasails occasionally being useful.
Next we move to the not sexy and impractical category. The two entrants in this segment are not making popular press headlines, but do overlap with the purported synthetic fuels silver bullet above. I’ve been holding off on committing to what I think will refuel the hardest to decarbonize segment of deepwater shipping, the longest third of near shore and most of deepwater shipping routes. Major players in the industry are laying their bets, and the two frontrunners have been synthetic methanol and synthetic ammonia. Both have serious drawbacks compared to what I think will actually refuel marine shipping, and I’ll lay them out here.
I assessed plans for manufacturing both fuels in Northern Africa and in regard to Maersk’s efforts. The intent is to manufacture green hydrogen and combine it with carbon and oxygen in the case of methanol and with nitrogen in the case of ammonia. Both processes are done globally today with black hydrogen coming from natural gas or coal. This isn’t rocket science, and we’ve been doing it for decades. The chemical plants aren’t going to get magically cheaper, and both substances are already much more expensive than bunker fuel and diesel used in shipping today. As soon as you assert that they are going to be manufactured with green or even blue hydrogen, costs just go up a lot.
Both share another problem, which is that they have lower energy density by both mass and volume.
Maritime fuel energy density chart courtesy DNV GL Environmental Advisory Services” data-image-caption=”Maritime fuel energy density chart courtesy DNV GL Environmental Advisory Services” data-medium-file=”https://cleantechnica.com/files/2022/10/Screen-Shot-2022-10-04-at-3.42.00-PM-400×187.png” data-large-file=”https://cleantechnica.com/files/2022/10/Screen-Shot-2022-10-04-at-3.42.00-PM-800×374.png” loading=”lazy” class=”size-full wp-image-278210″ src=”https://cleantechnica.com/files/2022/10/Screen-Shot-2022-10-04-at-3.42.00-PM.png” alt=”Maritime fuel energy density chart courtesy DNV GL Environmental Advisory Services” width=”1770″ height=”828″ srcset=”https://cleantechnica.com/files/2022/10/Screen-Shot-2022-10-04-at-3.42.00-PM.png 1770w, https://cleantechnica.com/files/2022/10/Screen-Shot-2022-10-04-at-3.42.00-PM-400×187.png 400w, https://cleantechnica.com/files/2022/10/Screen-Shot-2022-10-04-at-3.42.00-PM-800×374.png 800w, https://cleantechnica.com/files/2022/10/Screen-Shot-2022-10-04-at-3.42.00-PM-768×359.png 768w, https://cleantechnica.com/files/2022/10/Screen-Shot-2022-10-04-at-3.42.00-PM-1536×719.png 1536w” sizes=”(max-width: 1770px) 100vw, 1770px”/>
Maritime fuel energy density chart courtesy DNV GL Environmental Advisory Services
So they are both much more expensive, take up more cargo room, and have a weight penalty. This is a trifecta of economic doom for both of these alternatives. Fuel costs are already 50% or more of the average shipping lines’ expenses. Significantly increasing fuel costs while diminishing cargo volume has a multiplier effect on cost per ton of cargo.
To be clear, marine shipping will become more expensive, but synthesizing ammonia or methanol is so much more expensive, so unlikely to reduce in cost and so physically challenging to freight logistics that I think it’s hopium on the part of the shipping and logistics industry.
And that’s not the end of the problems, at least not for ammonia. It’s nasty stuff. It’s toxic to humans if they are exposed to it. If it mixes with water — and you’ll note this is about ships in water — it turns into a nasty corrosive substance that eats people’s lungs for lunch. Then it rapidly transforms into a third chemical which is also pretty unhealthy for humans. There are ammonia tankers plying the oceans today, but they are sealed and safety inspected vessels that are very definitely not tapping the ammonia to run the engines. The marine industry seems to be moving away from consideration of ammonia, which I think is a good thing.
So, what are the solutions, at least the unsexy ones that are also practical?
Well, the biggest wedge is batteries. All of inland shipping and two-thirds of near shore shipping is suitable for electrification and it’s quietly doing just that right now. I’m far from alone in saying that, by the way. A recent UC Berkeley study, Rapid battery cost declines accelerate the prospects of all-electric interregional container shipping by Kersley et al., lays out the math quite nicely. And the Redefining Energy podcast series just had Geir Bjørkeli, CEO of Corvus Energy, on to talk about how his firm has been quietly putting batteries in ships for over a decade, and how many operators are doing it unsubsidized because it’s saving them so much in fuel and maintenance costs. For every H2 ship headline, there are likely a hundred electrified boat deliveries. There are massive tourist ships plying Chinese inland waters, ferries around the world, and near shore and inland container ships already running on batteries.
Corvus does permanent in-ship installations of batteries with charging at ports, but many others are going down the route of containers of batteries that can be taken in and out of ships at ports, dropped in charging locations, and then put on different ships as needed. Container ships already have power hookups for freezer containers, and container transshipment management systems already know how to organize containers by category and many other things in ports, so this is a straightforward extension.
When I was speaking with Andy Tang, VP of energy storage and optimization for Wärtsilä, a few months ago, one of the things that came up was Tesla forcing the stationary battery deployers to containerize their batteries prior to shipping as opposed to onsite assembly. This is just more of the same. Commoditized li-ion and LFP batteries in standardized TEUs is dull as dishwater and it’s happening right now.
Of course, that does nothing for bulk shipping, but that segment is seriously declining in the coming years. Enormous amounts of bulk products that used to be in special bulk ships are now containerized. Oil, gas, and coal shipping — again, 40% of deepwater shipping — are going the way of the dodo bird, and aren’t going to be replaced with massively greater amounts of hydrogen or ammonia shipping, as much as the maritime shipyards and bulk operators might like them to. Raw iron ore is 15% of deepwater shipping and as I’ve stated, that’s another segment with both limited growth and declining shipping. The limited growth is due to increases in scrapping steel in electric steel minimills instead of making new steel. The declining shipping is due to increases in shipping costs favoring local processing, and changes in steel manufacturing making processing near the mines much more feasible as massive amounts of coal won’t be involved, just direct reduction with electricity similar to aluminum or via green hydrogen reduction of the iron ore.
So bulk shipping is going to decline but still persist, and that leaves container shipping as an increasing portion. Both can be electrified up to certain distances, with excellent convenience in the container shipping space.
So what else is just happening quietly without getting a lot of attention?
How about defouling? Even minor fouling can reduce efficiency by 10% to 16%, and major fouling can reduce a vessel’s speed by over 80%. This is a $36 billion annual expense between drag and defouling for the US alone. Now hypersonic transducers can be mounted on ships’ hulls and prevent even the beginning of fouling with very limited energy requirements, and due to high frequencies, little likelihood of marine life noise impacts. And instead of expensive divers defouling ships, there are now marine robots, basically underwater hull Roombas, that scrape the hull clean at much lower costs, so it can be done more frequently. No one will ever see or notice this, but ships will become much slipperier much more of the time because of better, cheaper defouling technologies, and ones that aren’t using the toxic chemicals that were used before.
Another big, boring wedge is just slowing down. While bulk carriers typically are slow-moving behemoths running under 10 knots, container ships have traditionally competed on speed of delivery, with faster and faster carriers. That history is laid out in the much recommended book,
The 2015 conference paper Slow Steaming Options Investigation Using Multi Criteria Decision Analysis Method by Dagkinis and Nikitakos quantifies the fuel savings from reducing speed, which are substantial.
Containership fuel variance by speed courtesy of authors Dagkinis/Nikitakos” data-image-caption=”Containership fuel variance by speed courtesy of authors Dagkinis/Nikitakos” data-medium-file=”https://cleantechnica.com/files/2022/10/Fuel-Consumption-by-Containership-Size-and-Speed-1-400×249.png” data-large-file=”https://cleantechnica.com/files/2022/10/Fuel-Consumption-by-Containership-Size-and-Speed-1.png” loading=”lazy” class=”size-full wp-image-278215″ src=”https://cleantechnica.com/files/2022/10/Fuel-Consumption-by-Containership-Size-and-Speed-1.png” alt=”Containership fuel variance by speed courtesy of authors Dagkinis/Nikitakos” width=”630″ height=”392″ srcset=”https://cleantechnica.com/files/2022/10/Fuel-Consumption-by-Containership-Size-and-Speed-1.png 630w, https://cleantechnica.com/files/2022/10/Fuel-Consumption-by-Containership-Size-and-Speed-1-400×249.png 400w” sizes=”(max-width: 630px) 100vw, 630px”/>
Containership fuel variance by speed courtesy of authors Dagkinis/Nikitakos
So yes, about as unsexy and practical as it’s possible to imagine is just slowing down ships. Remember that while this only applies to container ships, that’s fine as bulk carriers are going to dwindle in numbers, not increase.
And finally, for those ships that are just sailing too far to electrify, the answer is biodiesel, not methanol or ammonia, in my opinion. As the energy density of fuels chart shows, it’s well positioned on that metric, and carbon intensity of biofuels has plummeted in the past decade and will drop further. We now have stock cellulosic and other biofuel supply chains that are maturing and don’t take unnecessary land away from food, which isn’t actually a problem in any event. Manufacturing Jet A-1 SAF biofuels for aviation and biodiesel for the portion of shipping which can’t electrify is well within the carrying capacity of the Earth’s arable and semi-arable land, per my assessment of US land use for biofuel calculators, especially as global population growth is expected to stop between 2070 and 2100. Demand increases will no longer be driven by the combination of population growth and prosperity, but solely by prosperity. And biofuels are much cheaper than synthetic methanol and ammonia.
Aviation, per my assessment of that space, will be able to deliver transcontinental flights with battery-electric by 2060 or so, with most flights being battery-electric by 2100. As a result, the amount of biofuels consumed with their concerns will diminish through 2100 after peaking mid-century. Of course, as noted in my quadrant chart for ground transportation, we have to stop wasting any of the biofuels on that segment and preserve them for the really hard to decarbonize segments.
And so, there’s the sexy vs practical quadrant chart for marine transportation. It will feature novel hull designs, the hulls will be fouling free, the ships will be moving more slowly, there will be a much higher percentage of container ships, and only the longest routes will be burning fuels, while getting some assistance from parafoils when the conditions are right.
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