A matter of timing

In September 2013, Insight looked at MEPC’s decision to delay the implementation of Tier III NOx standards of 3.4 g/kwh within NOx emission control areas (ECAs) by five years. At its 66th session in London this April, the Committee adopted amendments to the MARPOL Convention that reversed this decision.

The amendments to MARPOL Annex VI regulation 13 on NOx mean Tier III standards will now be applied to marine diesel engines installed on ships constructed on or after 1 January 2016 that operate in ECAs designated to control NOx emissions. These NOx ECAs have currently been established in North America and the Caribbean.

However, IMO stopped short of implementing a fixed start date for newly designated ECAs, opting instead for flexible provisions for any ECA established after 2016.

Outside of ECAs, Tier II NOx controls still apply to diesel engines on ships constructed after 1 January 2011.

In 2016 NOx levels will be cut by more than 75% in ECAs

OEM options for NOx reduction

When the new legislation arrives it will cut NOx levels by more than 75% compared with current Tier II levels, and to achieve this more than one NOx reduction solution will be required.

The wide variety of technologies currently being evaluated include: selective catalytic reduction (SCR), exhaust gas recirculation (EGR), humidified air and water injection and high pressure turbocharging. Clearly these solutions now need to be ready for implementation in 2016, which means the pace of evaluation and testing must increase.

Right now it is still too early to predict which will be the most widely adopted solution. But, we can be sure that the impact on fuel consumption will be a key factor for success - especially as fuel costs represent a high proportion of total operating costs, and as CO₂ emissions regulations come into force.

Low sulphur fuels also under scrutiny

At the same meeting, a review of marine fuel oil was considered. MEPC has now set up a group to develop a method to determine the availability of fuel oil that complies with MARPOL Annex VI SOx requirements. The sulphur limit for fuel oil used on board ships is currently 3.50% m/m maximum outside ECAs – a level that is set to drop to 0.50% m/m on 1 January 2020.

However, depending on the outcome of the planned fuel oil review, which will be completed by 2018, the lower sulphur limit could be deferred to 1 January 2025.

Sulphur reduction timing could be affected by availability of compliant fuels

OEM options for sulphur reduction

Both single and dual fuel strategies are being considered to meet tightening sulphur emissions targets. Ship operators opting for a single fuel, run the ship solely on low sulphur fuel or use a cheaper residual fuel combined with scrubber technology. Others are using two different fuels – a residual fuel in international waters, and either low sulphur fuel or liquid natural gas (LNG) where lower sulphur levels are required.

Currently there is no ideal solution, and each strategy has its advantages and disadvantages. OEMs see the dual fuel strategy, using LNG, as the best option for meeting future sulphur reduction targets, but the ultimate decision is likely to be based on cost, ease of implementation and fuel availability.

Lubricant formulation

Aftertreatment systems will be needed to enable marine vessels to meet the very tough Tier III NOx limits. And, although SCR and EGR have both been tried and tested in other applications, their introduction to the marine world is unlikely to be straightforward.

EGR for example will require marine lubricants with enhanced soot handling and dispersancy to prevent an increase in soot and visible exhaust emissions, which would have severe implications for ship operators.

As for SCR, the key drawback here, apart from the additional urea equipment and infrastructure required, is the potential for catalyst poisoning.

Industry needs to draw on learnings gained from the use of this technology in other transport sectors so that some of the potential technical challenges can be anticipated, and hopefully avoided.

The changes to fuelling required to meet future sulphur limits will also bring lubricant formulation challenges. Low sulphur fuels for example introduce a requirement for lubricants with lower total base number (TBN) and improved wear control and better combustion performance. Also, where dual or multi-fuel engines are used, lubricants will need to provide advanced corrosion and wear protection.

Whatever timing MEPC sets for these future emissions reductions, it is clear that the changes required to meet the tough limits will impact lubricant formulations.

The wide variety of potential hardware, ship operation and fuel combinations that can be employed by OEMs and ship operators, combined with the fact that the development and approval of a marine lubricant is a long process, means industry collaboration is increasingly essential.

Infineum is already involved in a number of projects with OEMs, ship operators and with fuel and lubricant companies to ensure hardware technology and marine lubricant systems are successfully co-engineered in time to meet these regulatory challenges.

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