Just when the shipping industry has accepted that it must comply with the International Maritime Organization’s 0.5% global cap on sulphur content of emissions by 1 January 2020 – with no delays or exemptions – a new challenge presents itself: mapping a pathway to drastically reducing the carbon footprint of ships by 2050.

In line with the Paris Agreement on Climate Change of December 2015, the International Maritime Organisation (IMO), at the meeting of its Marine Environment Protection Committee in mid-April (MPEC 72), adopted an ‘Initial Strategy’ by April 2018, for a roadmap to slashing greenhouse gas (GHG) emissions from the international shipping sector by at least 50% over 2008 levels by 2050.

The aviation industry has already voluntarily set itself a 50% global CO2 reduction target by 2050 and shipping duly followed suit – partly to ward off the prospect of unilateral measures being imposed upon it in areas such as the European Union and China.

Indeed, environmentalists are already calling for the introduction of Zero Emission Vessels (ZEVs), in just the same way as some countries and car manufacturers are talking of phasing out petrol and diesel cars in favour of electric cars. For ships sailing the oceans however, it will be less simple (see box story below).

For now, shipping faces the immediate challenge of scaling back its sulphur emissions worldwide by 2020, as opposed to merely in Special Emission Control Areas around coasts with heightened environmental concerns as at present.

Three main solutions to the sulphur challenge are possible, each with its own potential downside.

  • First is to switch bunker supplies to a low sulphur variant of the Heavy Fuel Oil (LSHFO) commonly used in marine diesel engines. This very much depends on refineries being able to produce sufficient quantities of LSHFO at an attractive enough price. A significant price hike over ordinary HFO seems inevitable.
  • A second option is to fit emission abatement technology or ‘scrubbers’ to the ship’s smokestack, to clean emissions of their sulphur content. However, this equipment is both bulky and costly to fit, especially as it often requires modification work to the ship’s engine room, as well as constant monitoring of its performance.
  • The third solution currently gaining traction with the industry is a switch to Liquified Natural Gas (LNG), an altogether cleaner fuel. Requiring careful storage in hermetically sealed, cryogenic tanks to conserve its liquid – and highly condensed – state at minus 160 degrees centigrade, LNG was once thought potentially too dangerous in the event of a leak and possible conflagration of the resulting gas cloud. However, public perception of that danger seems to have eased, to the extent that cruise ships and ferries are routinely being ordered with LNG propulsion these days.

In late 2017, CMA CGM ordered nine LNG-powered 22,000 TEU new builds, considered a breakthrough order that may speed wider adoption of the new fuel in other vessel types and sizes.

The drawback of LNG remains the lack of a global bunkering infrastructure. Major ports and others with important ferry and cruise business are racing to have the necessary facilities in place, but that’s a far cry from having LNG fuel widely available in ports all around the world.

And then there’s the question of the lifespan of such LNG-fuelled vessels. Gas may be less polluting than oil (or its predecessor coal) but it is still a fossil fuel with Greenhouse Gas (GHG) levels almost as high. On any pathway to a shipping industry with reduced carbon footprint – let alone the newly coined term Zero Emission Vessels (ZEVs) – it is a transitional energy source at best (or even a diversion, according to some environmentalists).

Despite the pitfalls of these solutions, it is clear that shipowners have no choice but to comply with the ultra-low fuel sulphur content limit by 2020. IMO secretary-general Kitack Lim said recently that there was “no turning back” on the 2020 deadline, despite some calls to defer it until 2025. To further discourage any flouting of the rules, the IMO is moving towards banning the carriage of fuels with a higher sulphur content than 0.5% aboard any ship not fitted with a scrubber.

The trickier question now facing the IMO is how to implement its carbon reduction strategy in a way that is acceptable to all its Member States.

The International Chamber of Shipping (ICS), representing national shipowner bodies whose membership comprises more than 80% of the world merchant fleet, had lobbied hard for the IMO to adopt an ambitious carbon reduction target.

“The vision of ICS is zero CO2 emissions as soon as possible using alternative fuels and new propulsion technologies,” says Simon Bennett, ICS deputy secretary-general. “But so long as ships are dependent on fossils fuels, IMO Member States need to be both politically and technically realistic about what can be achieved in the short term if this is to be compatible with the legitimate concerns of emerging economies about the impact on trade and their sustainable development.”

The EU has already introduced a mandatory Measuring, Reporting and Verification (MRV) scheme for shipping emissions as of January 2018, whereby all vessels calling at EU ports must submit a record of their fuel consumption.

Many see the EU MRV as a move that paves the way for imposition of some form of ‘carbon tax’ on ships burning fossil fuels in the future. And while the IMO has introduced a comparable Data Collection System for fuel consumption, crucially this merely tallies up an industry total rather than itemizing the burn of individual ships – which is feared could lead to unfair targeting of certain vessels or types.

These days most would agree that shipping must do what it can to reduce its carbon footprint. Reduction of harmful sulphur emissions is already a good start towards a cleaner maritime industry, despite the operational challenges and extra cost involved.

Weaning ocean vessels off fossil fuels altogether is a far more serious problem however, requiring innovative ideas and advances in technology still to be discovered.

Future Fuels

LNG (liquefied natural gas) is considered the cleanest fossil fuel since it emits almost hardly any sulphur oxides or particulate matter in the form of soot, dust or fumes upon combustion. It also generates some 30% less carbon dioxide than fuel oil.

However, it still remains a fossil fuel and as such is considered only a transitional energy source on the pathway to any decarbonisation of shipping, in line with global attempts to arrest climate change.

Classification societies are at the forefront of examining what other future fuels and technologies hold most promise for the decarbonisation of shipping, to which end Lloyd’s Register (LR) jointly with University Maritime Advisory Services (UMAS) released a study entitled ‘Zero Emission Vessels 2030’ in December 2017.

If the IMO is to come up with an ambitious reduction strategy for greenhouse gases in line with the Paris Agreement, “ZEVs will need to be entering the fleet in 2030 and form a significant proportion of newbuilds from then on,” says LR by way of introduction to the premise of the report.

The report goes on assesses various technology options for ZEVs, covering both energy storage and propulsion plus auxiliary services, including combinations of batteries or fuel cells with motors and combustion engines, powered by the likes of biofuels, hydrogen or ammonia.

Batteries are somewhat dismissed by the study for large ocean-going ships because of size and weight restrictions. Likewise, biofuels are considered to carry with them negative societal implications since their production is at the expense of other land use or requires deforestation.

This leaves hydrogen-powered engines or fuel cells as one of the most attractive options going forward, and indeed LR has recently classed its first hydrogen-powered vessel, Hydroville, a dual-fuel engined commuter craft belonging to CMB of Antwerp. The vessel can run on either diesel fuel oil or gas – which is normally LNG but in this case Hydroville’s engines are modified to use hydrogen gas instead. CMB feels this technology suits larger vessels and vehicles better than fuel cells, while allowing the use of hydrogen’s totally clean burning properties.

“The advantage of hydrogen is that no CO2, particulate matter or sulphur oxides are released during combustion,” explains LR, calling the Hydroville project “a stepping stone towards the wider use of hydrogen as a fuel for combustion engines and alternative power generation technologies such as fuel cells.”

Synthetically produced ammonia also contains a high amount of hydrogen, making it a potential future carbon-free fuel for fuel cells.

At present, none of the potential future fuels or technologies compares favourably cost-wise with fossil fuels, LR points out. However, there remains plenty of scope for technological advances and/or different energy price scenarios to alter that equation, it notes. If components such as fuel cells, batteries and hydrogen storage become important components of another sector’s decarbonisation activities, these components may come down in price. Additionally, regulators may also step in to tilt the financial balance away from the use of fossil fuels if current actions to prevent climate change intensify.