Propulsion: What’s in the wind?

Written by Nick Blenkey
Wallenius Wilhelmsen plans to build the world’s first full-size, primarily wind-powered pure car and truck carrier.

Wallenius Wilhelmsen plans to build the world’s first full-size, primarily wind-powered pure car and truck carrier.

It’s often said that shipping is faced with making a change in propulsion systems as big as that from sail to steam. Could it just be that the next transition will be a return to sail? While that may be partly so, what’s certain is that major transition is already underway.

Clarkson’s Research reports that the first half of 2022 saw a record 268 alternate-fueled newbuilding vessels ordered, totaling 22 million gross tons and with a total contract value of $38 billion. This constituted 61% of all newbuild orders in tonnage terms, 38% on the basis of vessel numbers and 68% of overall contract value. Excluding LNG carriers, the number of vessels was 174, totaling 11.9 million gross tons with a total contract value of $18.4 billion (equating to 46% of gross tonnage, 29% of vessel numbers and 51% of contract value).

More than half (59%) of these alternately fueled newbuilds will be LNG dual fueled. Another 1.6% will be methanol fueled and 0.3% will be ethane fueled and 0.8% include battery hybrid propulsion. In addition, a further 16.3% of orders were “ammonia ready,” 0.8% of orders were “LNG ready” and 0.1% of orders have been “hydrogen ready.” This all adds up to more than 100% of the alternative-fuels-capable total as there is an increasing trend for orderers to opt for multiple fuels/ fuel-ready vessels to provide future optionality.

Clarkson’s also reported that energy saving technologies (ESTs) have been fitted on over 5,300 ships, accounting for 23.6% of fleet tonnage: including propeller ducts, rudder bulbs, rotor sails, wind kites and air lubrication systems. While the handful of rotor sails and other wind-assistance systems currently out there are, indeed, basically “energy savings devices,” there are plenty of advocates for ship designs where wind power could do rather more than that.

In the Wind

Oslo-headquartered Wallenius Wilhelmsen is planning to go far beyond that by building the world’s first full-size, primarily wind-powered pure car and truck carrier. To be called Orcelle Wind, the 220- by 40-meter ship will have the capacity to carry 7,000 vehicles at speeds of 10-12 knots under sail—a speed that can be increased with the help of an onboard supplemental power system. In addition to cars, the wind-powered vessel will also be able to transport heavy machinery and breakbulk products.

The main energy force comes from wind, using the Oceanbird wing sail concept developed by maritime consultancy Wallenius Marine, These have more in common with airplane wings than traditional sails. The wings consist of a core and a flap, optimizing the aerodynamics forces and are segmented. When entering harbors, passing under bridges or if the surface area needs to be reduced due to strong winds, the smaller segment folds into the other before the whole wing sail is tilted.

The design is planned to produce emission reductions of up to 90% relative to today’s best vessels.

Outside of a few starry-eyed visionaries, however, few people see a wholesale return to sail as being the answer for most ships on most routes.

Main Focus: Green Fuels

As the stats from Clarkson’s Research suggest, most of the mainstream focus is on new green fuels and on existing fuels that that can serve as a bridge to them. That implies that the internal combustion engine is going to be shipping’s prime mover for quite a long time.

What about steam turbines? The only oceangoing commercial ships in which they linger on in any significant number are some now rather elderly LNG carriers. However, if we take a little detour and consider nuclear as a possible future zero-emission fuel, the story changes. Those small molten salt reactors that have been promoted as a sort of “nuclear battery” for ships, don’t directly produce electricity, they produce heat. To turn that into electricity requires steam … and a turbine.

With the nuclear option yet a while away, LNG is head and shoulders the alternative fuel option most owners are considering and right now engine manufacturers and designers putting a lot of attention into reducing the methane slip emissions—particularly a problem with low-pressure Otto cycle gas engines — that have long been pointed to by critics of LNG as a marine fuel.

Engines that can burn methanol and ethane are already on the market and ammonia-burning engines will be with us long before green ammonia is widely available as a fuel.

Then there’s hydrogen. The smaller, the vessel, the more the possibilities open up. Mostly, hydrogen has been seen as most attractive for use in fuel cells and, in April this year, leading fuel cell developer Ballard Power Systems achieved an industry-first in gaining DNV type approval for its for its FCwave marine fuel cell module. The compact 200 kW FCwave modules can deliver up to 1.2 MW (6 modules) on a single skid occupying 5.5 square meters of floor space.

Meantime, hydrogen can also be burned in diesel engines and, as we reported in June U.K.-based Windcat Workboats has already taken delivery of the first CTV to be powered by a pair of MAN V12 diesels.

Where else is smart propulsion taking ships? Find out here.

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