August 17, 2014
The marine industry is increasingly exposed to the kind of complexity and regional variation in exhaust emissions legislation to which road transport sectors have been subject for some time. They include international requirements on air pollution emissions under Annex VI of IMO’s MARPOL Convention and additional regional and local regulations applied by bodies such as the European Union, the California Air Resources Board’s OGV regulations.
As a result, internationally trading vessels must be able to comply with global and regional emission standards concurrently through the ECA limits as well as unique requirements when trading to the Unites States.
As a result of these regulations, internationally trading vessels will need more complicated fuel systems, prime movers and after-treatment systems to comply with varying legislative limits in a cost-effective manner.
And the compliance requirements are becoming more demanding. The maximum permitted sulphur content of marine fuels for use in all ECAs is currently 1.0% and will decrease to 0.1% from January 1st 2015. This change will apply to all ECAs including the European SoxECA (SECA) areas of the Baltic Sea and the North Sea/ English Channel. The European SECAs are going through the process of becoming full ECAs to cover NOx limits too.
The IMO’s Tier III NOx emission standards within existing ECAs (North America and US Caribbean) will apply to vessels constructed after January 1st 2016 – and outside these areas, Tier II NOx controls apply. Tier I NOx requirements will be extended to each other ECAs effective the date of adoption.
In addition, the California Air Resources Board (CARB) Phase II requirements for the use of low-sulphur distillate fuel within 24 nautical miles of the coast of California came into force in January 2014.
A question often asked by ship owners is why it might not be preferable to use low-sulphur fuel oil (LSFO) in order to meet global and ECA requirements. The answer lies outside the shipping industry.
Oil refineries can be classified by the complexity of their crude oil processing and the amount of distillation residue that is converted to lighter, high-value products. Simple refineries with atmospheric distillation convert no residue and have a high yield of heavy fuel oil (HFO), while complex full conversion refineries may not yield any HFO.
If a refinery were to be configured for the production of very low-sulphur HFO, the hydro-treater for the residual fuel would be similar to that for distillate. However, much higher process pressures are required to remove the sulphur embedded in the large hydrocarbon molecules and extra equipment would be needed for handling residue contaminants.
The resulting investment cost would be up to five times that of a distillate hydro-treater. As the design and investment cost of a residue hydro-treater is similar to that of a hydrocracker and greater than then investment cost of a coking unit, it is unsurprising that refiners are more willing to invest in a similar or lower-cost option and produce higher-value distillates that can also be used in a variety of land-based markets, rather than lower-value, low-sulphur residual fuel for marine use.
Most ship owners and operators assume that the simplest option for ECA compliance is to practice fuel switching between HFO and LSFO or MGO/MDO (marine gas oil/marine diesel oil) before entering the ECA. However, as has been seen from the experience of the Baltic and North Sea SECAs, fuel switching creates a number of issues that owners must address to ensure smooth operations.
They include the installation of a separate pump for low-sulphur fuel oil operation, an additional cooler or chiller to control viscosity, separate piping arrangements with fuel changeover mechanism and the use of low base number lubrication oil for engines. Modification will likely be needed in electronic control systems for both the engines and boiler as well as to the burner control panel and relevant software. In addition, operations in cold areas may cause was in distillates to solidify, creating additional complexity.
ABS makes certain recommendations for owners and operators considering employing fuel switching. For example, they should include the process in their fuel oil management procedures and fuel oil management plan and ensure that the personnel responsible are properly trained. It is important to understand the time required to effectively raise and lower fuel temperatures.
Owners should also be diligent in testing incoming bunkers to make sure they comply with the proper specifications, as well as in performing periodic verification of the efficiency of onboard purification and treatment systems, with proper maintenance performed on the fuel-cleaning equipment.
Specific changeover procedures should be employed when switching between HFO and MGO and back, with similar procedures in place for HFO to MDO, MDO to MGO and vice versa, for main and auxiliary engines and boilers, all of which are to be included in the fuel oil changeover procedure manual.
For ships under ABS class, and ABS surveyor will issue a statement of fact upon completion of an inspection, which verifies that the vessel has a dedicated LSFO storage tank, that the piping system is arranged to allow main and auxiliary engines and the boiler to operate on LSFO. Structure, piping and control systems must be as per ABS- approved drawings; operational procedures for fuel changeover and operating procedures for using LSFO in engines and boilers are kept on board.
As an alternative to using low-sulphur fuels to comply with Regulation 14 of MARPOL Annex VI, the IMO permits the use of alternative means of compliance, normally characterized as the installation of an exhaust gas scrubber.
Any alternative must be approved by the ship’s flag administration, which also has an obligation to communicate that approval for IMO for onward distribution to the parties to the relevant IMO convention.
The main after-treatment systems used to comply with Regulation 14 are SOx scrubbers, which have performance requirements detailed in MEPC guidelines.
With the adoption of the revised Annex VI and the latest scrubber guidelines, the verification of this performance has been simplifies, based on a number of assumptions that allow verification by measurement of the SO2 /CO2 concentrations in the exhaust. A reduction efficiency of over 97% for 3.5% sulphur fuel is required to meet the 0.1% 2015 ECA limit.
Port state control verification during a US port call will typically include review of the vessel’s bunker delivery notes, verification that representative samples have been taken, a review of the fuel oil changeover procedures and logs and possibly further sampling of fuel oil and analysis of air emissions.
The EPA expects compliant fuel to be available for ships planning to operate in the North American ECA, just as it has been for North Sea and Baltic ECAs since 2010. But if owners, despite their best efforts, are unable to procure compliant fuel prior to entering the ECA, they must notify the EPA/Coast Guard and the flag administration.
For the Coast Guard/EPA to consider a temporary exemption, owners must submit a fuel oil non-availability report as soon as they are aware that they will be unable to procure and use compliant fuel oil in the ECA and no later than 96 hours prior to entering the ECA.
In addition to vessel particulars, the report requires a copy of the voyage plan as at the expected time of the entry into the ECA, including the vessel’s port of origin and destination and its first US port of arrival, and a detailed description of circumstances and actions taken.
Filing a report does not mean the ship is deemed in compliance with MARPOL Annex VI, and vessels must attempt to purchase compliant fuel from a US port prior to further transit in sufficient quantity to complete their voyage in the ECA.