The International Maritime Organisation, the United Nations body that oversees the industry, is meeting in London this week to strengthen measures intended to reduce its carbon footprint over the coming decades. Rich countries are supporting a carbon tax on shipping backed by the Marshall Islands, operator of one of the largest ship registries and one of the world’s most low-lying island states.
A draft agreement would commit the sector to net-zero emissions in 2050, Bloomberg News reported last week. The globe’s biggest exporter China, meanwhile, is attempting to rally developing countries to block tighter measures.
The shipping industry has a genuine problem getting from its current planned 50% reduction all the way to net zero. Ships are so vast and spend so long away from port that the technologies used to green power plants and cars won’t cut it. Only the smallest, short-haul ferries are likely to be able to run on batteries, let alone solar.
Wind power — the traditional engine of maritime trade until steam started to displace it in the 19th century — is too unpredictable and scarce to meet the needs of modern commerce, despite the regular release of exciting concept designs. An ocean line maximises its productivity by sending its ships on direct routes far from the most favourable winds, to set schedules that can’t be paused when the sea is becalmed. The small number of wind-assisted ships under construction are likely to make far less impact in greenhouse terms than, say, making rudders more aerodynamic.
That means the global fleet will be dependent on fuel of some sort. Most of the options on the table centre on potential liquid fuels that the industry is developing — from biodiesel, ammonia and methanol to synfuels made from smokestack gases, as well as LNG. About 48% of the tonnage on order this year will be able to run or switch to such alternative power sources, according to data provider Clarksons. If the industry wants to make it all the way to zero, however, it will have to consider another variety of fuel — uranium.That’s because the sector’s power requirements are enough to stretch the capacity of other green sources. At 11 exajoules, the global fleet consumes about as much energy as Brazil. Using biofuel or biomass-based methanol will push the limits of our agricultural land; synfuels risk embodying recycled emissions in materials badged as green. Powering shipping with green ammonia would require extraordinary amounts of wind and solar capacity, equivalent at a minimum to every turbine and panel that exists in the world today. The attraction of nuclear is that it’s already an established zero-carbon maritime technology, powering more than 160 military submarines and aircraft carriers. That would need to be drastically scaled up if it was to be used in merchant shipping, but it wouldn’t need to be close to universal. About 17,000 large ships, equivalent to a fifth of all hulls out there, are responsible for roughly 80% of the sector’s greenhouse emissions. One 2011 US study comparing conventional and nuclear-powered military vessels suggested atomic ships cost more, but only by about 19%. That’s more competitive than the other low-carbon fuel options out there — and, these days, possibly cheaper than the current, diesel-heavy fuel mix in conventional vessels.
BloombergThe main problem is one of regulation. Nuclear energy’s image problem is particularly profound when it comes to the oceans, as evidenced by the vocal protests around the impending release of waste water from Japan’s Fukushima Daiichi atomic plant site. Many countries restrict nuclear power on their territory. The two largest container lines, Mediterranean Shipping Co. and A.P. Moller-Maersk A/S, have roots in Italy and Denmark, nations with strong anti-nuclear traditions.
These aren’t idle fears. The proliferation risks from thousands of highly enriched uranium reactors plying the high seas are substantial: Merchant ships don’t carry the arsenal that military vessels can use to deter piracy. Accidents would pose further problems with the risk of material leaks — several dozen large ships are lost every year, according to Allianz SE.
And yet the trend of the shipping industry over the past decade has been one of consolidation among a handful of national champions in China, Japan, South Korea, Taiwan and Europe. A network where nuclear-powered megaships ply trunk routes between the biggest ports while alternative-fuelled feeder vessels supply smaller harbours would closely resemble the structure the industry is already developing. If we want the shipping trade to get all the way to net zero, nuclear may be the only way to achieve it.
