Hard Sail Power Might Have Niche In Roro Vehicle Shipping
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Sails on ships are a romantic and idealized vision of the world. Our history as a species includes innumerable tiny vessels pushed by wind across great expanses of featureless ocean, bold explorers and traders risking all on the science of sextants and the vagaries of the weather. But in recent years it’s been making a comeback due to the completely unromantic reality of climate change. All our shipping produces lots of carbon dioxide, along with other greenhouse gases. Maybe sails are due for a comeback?
The impetus for this piece is a discussion this week with long term contact Elisabet Liljeblad, a Swede with a PhD in electrophysics, time spent as a Swedish soldier and signalist in a reconnaissance platoon in Afghanistan keeping Afghani women safe, time with Volvo driving sustainability, time with Swedish firm Stena trying to drive decarbonize its shipping concerns, and now working with Sweden’s Wallenius family’s Soya Group doing the same. Oh, and her boss Per Tunell, who while not having the quite extraordinary backstory Elisabet has as far as I’m aware — I’ve left out a few things even with this lengthy intro — has been working with Soya Group on decarbonizing and cleaning up shipping for almost 20 years with his naval architect and MBA background.
Soya Group has two focuses in shipping. The first is moving cars, other light vehicles, and trucks from where they are manufactured to where they are sold globally. There are about 600 roro — roll on roll off — ships operating worldwide, a large percentage of them delivering ships and trucks to markets, per 360 kilogram (800 pound) gorilla in the space, Wallenius Wilhemson. Yes, Soya Group is in a joint venture with another firm and has a massive market share, 130 pure car and truck carriers (PCTCs) for the global market and another firm that serves only the European near shore roro market, a joint venture with the other gorilla in the space, NYK. Yes, they are perhaps 25% of the global supplier for this kind of shipping.
The second focus is sustainability. The firm, being privately held, can more easily take a long view, not shaped by the quarterly analyst meetings that have made US capitalism a sad combination of rich, dysfunctional and so often uncreatively destructive. For 20 years, the firm has been working on sustainable shipping, something that they were virtually alone in doing as a major firm two decades ago. As Tunell, who has been in the sustainability group for three-quarters or so of that time and now leads it, told me, 20 years ago it was easy to talk about sustainability in shipping because no one knew what it meant or how to do it. But time has moved on.
As always, context is important. Roro shipping isn’t the biggest part of shipping, by far. There are about ten times as many container ships, and they are about twice as big in all dimensions, meaning perhaps eight times as much cargo volume per ship, hence maybe eighty times as much in the fleet. Then there are bulk ships, about twice as many as container ships right now. Once again, they are on average about twice the dimensions in every direction as roro ships, so that’s about 160 times the shipping volume. As a reminder, that massive bulk fleet is going to be diminishing radically, as 40% of it or so is moving coal, oil, and gas from where it’s extracted to where it’s burned, and another 15% is raw iron ore steaming to the same ports as coal. Both are in structural decline, so the ratio between container ships and bulk ships is going to change radically in the next three decades.
Roro ships are measured in car equivalent units (CEUs). It represents the number of standard-sized cars (usually based on a compact car size, around 4.5 meters long) that a RoRo ship can carry. Mid-sized ones like Soya Group’s European short sea ones have a 3,000 to 5,000 CEU capacity. Their big ones that cross oceans have an 8,000 CEU capacity. By contrast, big container ships carry 24,000 twenty foot equivalent units (TEUs), which are longer, taller, and wider than compact cars, as well as carrying cargo typically weighing multiples of a car’s weight.
The other useful thing to know about roro ships is that they have flat tops that nothing goes in and out of, unlike bulk carriers which have huge hatches which are opened to move bulks in and out in various mechanized ways, and container ships, which are stacked with containers, unsurprisingly. Roro ships have vehicles which drive on and off via a multilane road in the rear, basically like a big car ferry if you’ve ridden one. What this means is that the tops of roro ships are basically unused space right now.
All of this discussion leads to my position on sails for modern cargo ships. This is an updated maritime shipping sexy vs meh chart from a series I published a couple of years ago. You’ll note that hard sails — carbon fiber or metal, solid-skinned foils which catch the wind — are in the sexy but foolish quadrant, while parafoils bridge the quadrants, being both oversold and pragmatic.
A big part of my position on wind power for ships is that ships are part of an efficient system that includes ports. A great number of things I’ve seen regarding maritime shipping bound the engineering solution from tank to wake, a clearly inaccurate box to consider, and few if any articulate how ships will work in ports. Ships are big and expensive machines, but ports are bigger and much more expensive machines. There are roughly 900 around the world and the amount of freight they transit daily dwarfs the largest ship. Container ships need efficient cranes to yank containers out of them to the straddle carriers and reach stackers that shuffle them like mahjong tiles in the massive container storage yards. Bulk carriers need overhead gantries with hoses, scoops, and conveyor belts to get the liquids and solids on and off of the ships. Neither set of overhead infrastructure will work well with rigid sails, even if they fold flat against the hull.
That’s why I think autofurling, bow-mounted parafoils are going to be the biggest wedge in sail power. Even then, I think it’s going be 10% to 20% of a subset of routes, not a 90% solution.
But Soya Group has been working on rigid sails for 14 years, with a masters thesis, lots of internal design work, initial design concepts, and now a project to add a hard foil wing to an existing roro ship. Their design point was a 90% energy solution. A reasonable amount of the discussion — when we weren’t agreeing violently on ammonia as a shipping fuel being an absurd idea and ship efficiency being a huge wedge, among other points of violent agreement — was about this.
More recently, only a year ago, I looked at various of the International Council on Clean Transportation’s maritime shipping studies and found not only an absurd focus on hydrogen, but an attachment to rigid sails on a variety of vessels that were hard to imagine sporting them. When I looked at the routes they had used as examples, I found bridges that the ships and sails wouldn’t fit under. When ships can’t get into even a subset of ports because they don’t fit under bridges, that’s a real problem.
Finally, there’s a ship owner and ship operator conflict. Ship owners often aren’t the ones who operate the ships. Ships are like office buildings, leased out to firms which need the space and incur the operational expenses. The ship owners pay for the ships. The operators pay to run them. This means that capital expenditures for things like sails are borne by the ship owners, but the benefits accrue to the ship operators. In buildings, this means that efficiency measures are hard to sell because they cost the owners money and save the tenants money, but the negotiations are in favor of the tenants. Same thing with ships.
Sails make ships cheaper but more complex to operate, costing the owners and benefiting the operators. That’s another issue which makes sails unlikely to be a big wedge in maritime shipping decarbonization.
But Soya Group designs and builds ships, owns ships, and operates ships, at least in joint ventures with Wilhelmson and NYK. And it has mostly roro ships where sails run into bridge height issues, but don’t run into issues with cranes, conveyor belts, or scoops. If any shipping concern has the success conditions for hard sails, it’s likely Soya Group.
One of my nerd concerns about sails on big ships is that they aren’t designed for them. This is amplified for roro ships because they are tall, with multiple car/truck decks making them big, vertical slabs powering through the waves. That means the sails start much higher off the water. That means the principal of leverage is amplified as the force on a longer lever is further from the point of the pivot. The forces have to be very large to move a 200-meter long, 80,000 ton slab of steel through the seas. On a roro ship, this means more force trying to make a ship which really doesn’t want to heel over heel over. The expensive auto flesh inside the ship really wants the ship to be level, not heeling into the wind and bouncing through waves.
But it’s not like this isn’t an obvious concern. From outside the industry, I can spot this, and unlike ammonia in engine rooms or hydrogen in fuel cells, the concerns are relatively basic to address. According to Tunell — and mulling over the mechanics of it makes me concur — broadening the beam of ships designed with sails in mind addresses this concern sufficiently.
This isn’t a retrofit concern, where limitations compound, but a roro ship designed from the water up for hard sails. This isn’t a container ship where the containers get in the way of any attempt to add sails and sails would get in the way of cranes. This is isn’t a bulk carrier — which are going to plummet in number as coal, oil, and gas stop being shipped, so aren’t being built in anywhere near the numbers they once were — where the sails would have to be shifted to one side of the hull, as Bar Technologies’ prototype does, and will still get in the way of getting bulks into and out of the ship.
And at least for Soya Group, the owner-operator conflict doesn’t really exist, nor are they subject to the North American corporate dysfunction caused by fiduciary responsibility being solely to the owners and their profits. Or at least, Soya Group’s owners actually care about sustainability and are willing to potentially forego profit.
Further, Soya Group has done Atlantic route modeling with ten years of weather data and found that they could average 10.5 knots — compared to 11-12 knots for bulks and the energy crisis imposed 12-14 knots for container ships — with 90% fuel savings. This is in the ballpark for meeting schedules and achieving profits, especially when 90% of operational fuel costs disappear. Fuel costs are in the range of 40% to 60% of expenses, so getting rid of most of those would allow market share gains with higher profits. No price war, just a cheaper product with different characteristics being economically more competitive.
If they succeed, they’ll take market share and make more profits, and as a result, all other roro ship operators will adapt or fail. That’s pretty good, and Soya Group has been 14 years in the making of this attempt. If the 600 or so roro ships, or at least the transoceanic subset of them, mostly end up with sails, that will be a strong positive, and it might happen. I’m pretty sure all of their short sea ships will just end up with batteries in the end.
But it doesn’t change the dynamics for the vastly more freight that moves by bulk carrier and container ships, in my opinion. The conditions for success just aren’t there. If they adopt sail power, it will much more likely be bow-mounted parafoils providing 10% to 20% of energy on some routes. And bulk carriers and container ships move a lot more cargo, likely 99% by volume and mass, if not value, than roro ships. It’s a niche that Soya Group has a dominant market share in, but not a huge one by the measure of maritime shipping energy used.
All this is to say that when I next update the maritime shipping decarbonization quadrant chart, I’ll need to move the hard sails over to be more aligned with the parafoils. I feel so Keynesian, or perhaps Bayesian.
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