SOx reduction in exhaust emissions

If meeting the NOx requirements has been difficult, the regulations concerning SOx reduction in exhaust emissions is potentially the most expensive regulation that shipping has ever had to meet. More to the point, the effect of SOx regulations will be felt by almost every vessel afloat regardless of age. This is because, unlike the NOx rules which apply to the engine rather than the ship, SOx rules fall on the ship itself.

The full impact of the SOx rules is yet to come as is detailed in the table below, from which it can be seen that apart from a small reduction in the limit permitted outside of ECAs that came into effect in 2012, most of the regulation has so far been experienced only by ships operating in the four ECAs that presently exist. There are some other local regulations that have wider application but the costly blow will fall in 2020 or 2025.

As can be seen from the table MARPOL sets limits by mass for the sulphur content of fuels as the primary means for controlling SOx emissions from ships. Because it is purely a product of the combustion process, SOx is only an issue for vessels burning residual fuels either in diesel engines or in boilers. Ships that operate purely on distillates, LNG or any of the newer gas fuels that do not contain sulphur are not affected by any of the regulations controlling SOx and are saved the additional expense of complying with the requirements of MARPOL.

It was initially intended that the only means of compliance would be to use fuels that met the regulations but under pressure from ship operators it was agreed that abatement technology would also eb permitted and in 2009, the MEPC.184(59) guidelines for Exhaust Gas Cleaning Systems (EGCS) were adopted. These guidelines enable a ship to achieve low-sulphur requirements by water washing the exhaust gas stream prior to discharge to the atmosphere. Each country party to Annex VI needs to ensure that its port and terminal facilities can accommodate residues from exhaust gas cleaning systems. Reducing SOx levels in exhaust emissions can come about in one of two ways. Either the sulphur level in fuel has to be reduced or abatement technology – commonly referred to as scrubbing – has to be employed. Unlike with NOx, there are no adjustments that engine manufacturers can make but the use of low sulphur fuel requires additional precautions that need to be taken in the choice of engine lubricants.

Lubricants need to be matched to fuels in order to avoid excess corrosion or lacquering which are the extremes of mis-matching. Tribology – the science of interacting surfaces, friction, wear and lubrication – is an important part of engine and lubricant R&D. Attempts have been made by most lubricant makers to develop a universal lubricant for engines that can cope with all fuel types but success has so far been elusive.

When the SOx timetable and emission limits were being determined over a decade ago, many within the industry believed that the only means to meet them would be a wholesale switch to distillate fuels. In a debate that became very heated at times there were even calls for residual fuels to be banned completely so that all ships would be obliged to burn the same fuel and thus ensure a level playing field.

Even though the price differential between standard and low-sulphur fuels of around $70 was then much smaller than it is today, the idea of a ban on residuals did not sit well with many ship operators. While the first ECA sulphur limits were achievable using low-sulphur fuel oils, the reduction to 0.1% in 2015 was always going to be impossible to meet given the state of technology at the time.

Another move over the last five to ten years has been the promotion of LNG as a fuel. Just as with helping to meet the NOx rules, LNG’s main advantage was its composition which under most circumstances does not include sulphur. Despite some very loud voices raised in favour of LNG as the fuel of choice for future ships, it has been apparent that most operators do not share the same opinion. Leaving aside the LNG carriers which run on boil of gas from the cargo, most gas burning ships have been Norwegian flagged ships that have benefitted from financial incentives and grants from the Norwegian NOx Fund.

More recently there has been some more interest shown by US container ship operators. In part this has been caused by the advent of the US ECAs which regulate both NOx and SOx and partly by the cheap LNG being produced in the US from ‘fracking’. As the SOx reduction in ECAs drew closer, a large contingent of industry expects were expecting owners of existing vessels to opt for running on distillate fuels and for operators ordering new vessels installing dual-fuel or even pure gas burning engines, some within the industry pinned their faith on fledgling scrubber technology. Others may have been slower but with the deadline of 1 January 2015 now passed, the take up of scrubbers is beginning to accelerate but the increase in LNG-fuelled vessels has been much lower than anticipated. Ships which do not have scrubbers and which cannot burn LNG or another alternative have been obliged to burn distillates in ECAs.

Setting limits on sulphur

Sulphur levels in fuels are regulated mainly because SOx is considered as the main cause of acid rain but also because it is a component of the group of small particulate matter referred to as PM2.5. SOx is not considered to be a GHG and in fact it is acknowledged that its atmospheric effect is as coolant.

The production of SOx caused naturally by volcanic activity and most recently as a result of increased burning of coal for power production in China has been cited as a cause for the plateauing of the global temperature trend over the last 18 years. One geo-engineering project aimed at reducing global warming suggests that the atmosphere actually be seeded with sulphate particulates. The irony of such should not be lost upon ship operators obliged to take expensive measures to reduce SOx under MARPOL Annex VI.

January 2015 saw the penultimate reduction in permitted sulphur limits in fuels come into effect. All vessels falling under the regulations of MARPOL Annex VI are now only permitted to use fuel with a maximum sulphur level of 0.1% m/m or make use of exhaust gas cleaning systems when operating in ECAs. This means that for vessels previously affected by the California Ocean-Going Vessels Fuel Regulation, the same levels now extend to all US waters. Most of the world has adopted the MARPOL ANNEX VI regulations but there are some regional regulations in force that go beyond it. Notably these are all ports in member states of the EU where a 0.1% limits is in place under the EU Sulphur Directive (which also covers ports outside of the two Northern European SECA zones) and Hong Kong.

In Europe, the 0.1% limit now applies throughout the Baltic and North Sea SECAs rather than just in EU member state ports. Although there is no SECA covering any of the Mediterranean or the Atlantic coasts of Portugal, Spain, France, Irish Republic and UK and parts of Norway, EU and Norwegian rules limit sulphur levels in fuels used in port to the same 0.1% as in the SECAs.
In Finland the Finnish Transport Safety Agency (Trafi), the Finnish Border Guard and the police will all monitor emissions from shipping. Since the country is inside the Baltic Sea SECA and is an EU member state strict SOx regulations apply. Because it is believed that failure to comply with the regulations is a deliberate act done to save costs, the price difference between high- and low-sulphur fuels – gains are considered as ‘illegal financial gains’ and their value can be claimed by the Finnish authorities as compensation. Such penalties are considered more tangible than fines or other punishments. Trafi has estimated that if ships use only low-sulphur fuel, the provisions will increase Finland’s maritime transport costs by around €460 million/year, and by €120 million/year if scrubbers are installed in ships.

China is the latest country to apply local regulation following on from the sulphur cap of 0.05% m/m for locally supplied marine light diesel under the Hong Kong Air Pollution Control (Marine Light Diesel) Regulation which came into force on 1April 2014 in December 2015, China announced the establishment of ship Emission Control Areas (ECAs) in the Pearl River Delta, the Yangtze River Delta and the Bohai Bay rim area.

The implementation schedule for the new requirements is as follows:

* From 1 January 2016, some ports (if the port condition allows) within the control areas may implement the requirement for use of fuel with 0.5% m/m sulphur content or below when ships are alongside or at anchor.  Note that this is for any port within the control area, not just the key/core ports;
* From 1 January 2017, key/core ports of control areas shall implement the requirements for use of fuel with 0.5% m/m sulphur content or below when ships are alongside or at anchor;
* From 1 January 2018, all ports within control areas shall implement requirements for use of fuel with 0.5% m/m sulphur content or below when ships are alongside or at anchor; and
* From 1 January 2019, ships entering into control areas shall use fuel with 0.5% m/m sulphur content or below.
It should be noted that following an assessment of the effects of the above actions China will possibly implement requirements for use of fuel with 0.1% m/m sulphur content or below after 31 December 2019.

The requirements for ships at berth or at anchor are applicable from one hour after ships are berthed to one hour before departure. Ships may use other alternative measures to reduce emissions, such as shore power, clean energy or scrubbers.