The International Maritime Organisation (IMO), a United Nations agency, regulates shipping worldwide. In London in July, its marine environment protection committee agreed that member nations would accelerate their reductions in annual maritime emissions of greenhouse gases. They revised their original 50 per cent target reduction, as compared with 2008 levels, by 2050 to instead “near-zero”. However, a number of green lobbyists accused the committee of insufficient urgency.
Last December, the European Council and European Parliament included maritime transport within the European Union’s emission trading scheme. Ship operators will consequently have to pay for carbon emissions on a phased scale from next year, reaching 100 per cent by 2026.
The IMO has prescribed a number of indexes to measure a vessel’s carbon emissions, so that individual ships can be compared. In general, vessels with stronger assessments should be more likely to win cargo contracts. Older ships may be forced to reduce their speeds, to meet the maximum allowable emission thresholds. The indexes are not prescriptive, and thus individual shipowners and operators may choose any of a number of complementary technologies to achieve the targets.
Hull designs are generally considered to be close to their maximum potentials, and so unlikely to deliver substantial operating improvements. Bulbous bows are arguably the most widely adopted innovation since the last century, first appearing on the German sister ships SS Bremen and Europa for the North Atlantic liner route in the late 1920s. Shaped bows produce reflections which tend to cancel oncoming waves, thus reducing the friction on the hull.
Anti-fouling paints can help lower adhesion from marine organisms such as barnacles. However, they tend to lose their effectiveness over time, and may leach chemicals or heavy metals (such as copper) into the sea. Several firms – such as Norway’s Jotun, Denmark’s Hempel, and Nanotech Marine in Cornwall – are actively trialling novel coatings but there is as yet no widely accepted solution.
The US navy first experimented with injecting streams of air bubbles below ships’ hulls in the 1940s, so as to reduce noise and improve undersea warfare capabilities. In 2010, Mitsubishi introduced its “air lubrication” system, which builds a cushion of air below a hull to improve hydrodynamic performance. It is mainly intended for flat-hulled vessels, such as container transports and tankers, achieving up to 15 per cent reduction in fuel consumption. Challenges include ensuring a uniform bubble size along the hull length, and preventing excessive vibration of the ships propellers from the air stream bed at the stern.
Norway has led the world in electrifying its car ferry fleet, both retrofitting existing vessels and commissioning all-electric new ones
Modern marine engines are increasingly capable of using multiple fuels, to reduce pollution and carbon emissions. Wärtsilä, a Finnish leading marine engine manufacturer, was one of the first companies to produce a dual-fuel marine engine in 2001. The industry is moving away from traditional heavy fuel oil and diesel towards cleaner liquid natural gas, and ideally to reduced emission biofuel blends.
Norway has led the world in electrifying its car ferry fleet, both retrofitting existing vessels and commissioning all-electric new ones. However, an Australian shipbuilder, Incat Tasmania, has just announced the construction of the largest battery-electric ship worldwide yet, a 225-vehicle car ferry (a similar capacity to the Irish Ferries Dublin Swift ship). The on-board 40 megawatt-hour energy storage system will reputedly be four times larger than any other to date.
While some may wish to see a return to the sailing clippers of the 19th century, there is considerable interest in exploiting wind for today’s container ships and tankers.
In 1924, German engineer Anton Flettner added two 15m-high cylindrical spinning rotors to the deck of the schooner Buckau. When powered by a small engine, the rotation produces an air pressure differential across each cylinder, yielding a propulsive force. The physics is similar to that of “curve balls” in sports. In 2008, German wind turbine company Enercon added four Flettner-style rotor sails to its E-Ship 1 cargo vessel, used to transport wind turbine blades. Since 2014, Finnish Norsepower has installed rotor sails on several ships, including the ferry M/V Estraden, cargo ship Fehn Pollux, tanker Maersk Pelican and five tilting rotor sails on the very large ore carrier Guaibamax.
Hamburg-based SkySails has created a large foil kite, resembling those used in kite surfing. The MS Beluga SkySails container ship was the first to use the system, in a 2008 Atlantic crossing from Germany to Venezuela. Average fuel savings of about 5 per cent have been reported, but the system has not been widely adopted.
UK design consultancy BAR was spun out of Ben Ainslie’s 2017 Americas Cup yacht racing team. Working with Yara Marine Technologies in Norway, two 38m high “WindWing” sails have recently been fitted to the Pryxis Ocean bulk carrier. The ship is currently on her maiden voyage from Shanghai via Singapore and Port Elizabeth to arrive in Brazil on September 14th.
Until recently, the marine sector has largely escaped regulation over carbon emissions. The urgency to now evolve the industry provides intriguing opportunities for innovation.
