Although shipping is generally seen as a fuel efficient and ‘carbon friendly’ mode of transport, the industry is facing increasing pressure from regulators to improve its overall environmental performance – with particular focus on emissions to air. Therefore, new global regulations and regional schemes like Emission Control Areas (ECAs) will no doubt have a significant impact on emissions from shipping in the years to come. Sulfur ECAs are already in force in the Baltic Sea and North Sea areas, but new areas are likely to be defined in the near future.
Currently, the levels of sulphur oxide (SOx) emissions from the use of high sulphur marine heavy fuels (HSF) are significant, and recent regulations proposed by the IMO are strongly focused on tightening up the maximum allowed worldwide sulphur cap. However, the proposal accepts that technical abatement solutions are used to reduce SOx emissions from the stack to levels equivalent to burning a fuel with a specific sulphur content. It remains to be seen which solution will prove to be most viable – use of abatement technology (scrubbers) or a switch to low sulphur fuels.
Proposed sulphur caps likely to be finally agreed by the IMO in July 2009:
Global Sulphur Cap:
1-Jan 2012: 4.50 % ’ 3.50 %
1-Jan 2020: 3.50 % ’ 0.50 %ECA Sulphur Cap:
1-Mar 2010: 1.50 % ’ 1.00 %
1-Jan 2015: 1.00 % ’ 0,10%
Switching between high sulphur and low sulphur fuel requires a good system for keeping track of fuels segregated on board and may even represent an operational risk during the change-over process in congested areas, hence a complete switch to low sulphur fuel would be the desirable – albeit costly – solution. Recent reports show that continuous operation on low sulphur fuel will not cause any technical problems to the engine, but may require a change of components – e.g. the injection system to cater for low viscosity of distillate type fuels. The same applies for boilers operating on distillate fuels where injection nozzles, burners and fuel pumps will need to be modified or changed in order to work properly with low viscosity fuels.
Nitrogen oxide (NOx) emissions, having significant negative health and environmental impact, are also attracting regulatory focus and IMO has suggested reductions that will apply for new buildings already from 2011. NOx emissions from burning heavy fuel oil in diesel engines are mainly the result of high combustion temperatures in such engines and the relatively long reaction period during the combustion process.
Proposed NOx regulation limits likely to be finally agreed by the IMO in July 2009 (for <130 rpm engines):
Tier I: Ships built 1-Jan-00 to 1-Jan-11 (17.0 g/kWh = today’s limit)
Tier II: Ships built after 1-Jan-11 (14.4 g/kWh)
Tier III: Ships built after 1-Jan-16 and operating in NOx-ECAs (3.4 g/kWh)
Ships (>5MW) built 1-Jan-90 to 1-Jan-00 to comply with Tier I – provided that an approved method for NOx reduction is available and cost effective.
While the SOx issue can be resolved either through improved production technology for marine fuels at the refinery or by onboard abatement systems, the NOx emissions are less dependent on fuel quality. Reduction of NOx emissions will thus have to be addressed onboard the vessel and can be achieved by modifications to the engine or by installation of a Selective Catalytic Reactor (SCR) unit to clean out NOx from the exhaust gases. Another alternative is switching to completely new fuel types such as LNG, which would reduce NOx significantly.
Whichever solution is chosen for onboard reduction of NOx and SOx emissions, one concern is the added operational complexity and the requirement for skilled personnel to maintain the equipment. The crew also will have to provide continuous documentation to authorities to prove that the equipment’s efficiency is maintained. This is going to be a challenge.
When it comes to CO2 emissions, these are almost directly proportional to the amount of fossil fuel being consumed. Since liquid petroleum fuel is likely to remain the dominant energy source for marine propulsion in the foreseeable future, effective energy management and optimization will be the only practical ways of reducing CO2 emissions. This can be achieved by introducing improved technologies such as new hull shapes and designs for less resistance, building bigger ships, better hull and propeller surface treatment and coatings and improved propulsion and engine designs as well as heat recovery systems for optimizing energy utilization.
Apart from technological improvements, significant gains can be achieved through more efficient operational patterns which reduce fuel consumption. Recent studies have documented that the application of available tools for voyage planning, weather routing, adjustment of auto-pilot systems and optimized use of onboard energy consumers may contribute to fuel savings in the range of 5% to 12% – in some cases more – without making any design or structural modifications to the vessel itself.
Further, substantial savings can be achieved by speed optimization. The potential for savings through slow steaming is dramatic for certain ships types, particularly ships like container vessels that normally operate at high speeds. However, various consequences must be taken into account, including logistical implications, time charter contract terms, port infrastructures, impact on overall transportation capacity and financial considerations.
Due to the factors mentioned, slow steaming was until recently regarded as a non-topic, but we now see that ship operators are implementing this option and are able to overcome the obstacles – with significant fuel savings as a result.
In addition to improving their environmental performance, unpredictable marine fuel prices and shipping day rates are incentives for ship operators to reduce fuel consumption and overall operating costs. Irrespective of the main driver, the fact remains that more environmental friendly operation in most cases goes hand-in-hand with a positive impact on the financial bottom line. In this respect, both ship operator and charterer/cargo owner should have a common interest and be in a win-win situation.
Land-based industries are under pressure to significantly reduce their emission levels in order to comply with new regulations and the (beyond) Kyoto protocol obligations. Likewise there will be increased pressure on shipping to adopt effective means for reducing fuel consumption in order to maintain its image as a sustainable mode of transportation.
In this respect, it will be important to identify viable alternatives and preferably establish incentive schemes to catalyze this process. One critical success factor for effective implementation of such schemes is to ensure that a level playing field is maintained within the shipping industry. Solutions must be global, not regional.
Another important success factor is to make efficient use of reliable environmental accounting data to establish baselines and to define industry best practices, and apply commonly understood benchmarking tools to compare performance up against such standards. Without widely accepted baselines, an environmental performance rating for ships and their emissions will be difficult to achieve. A reliable benchmark will also be a fundamental requirement for individual ships and fleets to demonstrate continuous improvement of their environmental performance over time.