Section 17.4 Annex VI: Prevention of Air Pollution (SOx, NOx, EEDI, SEEMP)

MARPOL Annex VI sets limits on Sulphur Oxide (SOx) and Nitrogen Oxide (NOx) emissions from ship exhausts and prohibits deliberate emissions of Ozone Depleting Substances (ODS). It also includes regulations concerning ship energy efficiency (EEDI, SEEMP, EEXI, CII). This Annex has seen significant updates and has major operational and technical implications for bulk carriers.

Key Requirements and Aspects for Bulk Carriers:

1. Sulphur Oxides (SOx) and Particulate Matter (PM):

Global Sulphur Limit: Since 1 January 2020, the global limit for sulphur content in fuel oil used onboard ships is 0.50% m/m (mass by mass).

Emission Control Areas (ECAs): Within designated ECAs (e.g., Baltic Sea, North Sea, North American ECA, US Caribbean Sea ECA), a stricter limit of 0.10% m/m applies.

Compliance Methods: Ships can meet these limits by:

Using compliant fuel oil (Very Low Sulphur Fuel Oil – VLSFO, or Marine Gas Oil/Marine Diesel Oil – MGO/MDO).

Using an approved Exhaust Gas Cleaning System (EGCS), commonly known as a “scrubber,” which cleans the exhaust gases before emission, allowing the use of higher sulphur fuel oil (HSFO). EGCS operation is subject to strict monitoring and record-keeping, and washwater discharge criteria apply.

Using alternative fuels with low or zero sulphur content (e.g., LNG, Methanol).

Fuel Oil Availability and Quality: Regulations require bunker suppliers to provide compliant fuel and maintain Bunker Delivery Notes (BDNs) detailing fuel properties, including sulphur content. Ships must retain BDNs for three years.

Fuel Oil Changeover Procedures: Ships operating both inside and outside ECAs using different fuels must have written procedures for fuel changeover and record these operations.

2. Nitrogen Oxides (NOx):

Engine Tier Standards: NOx emissions are controlled by applying engine-specific limits based on the engine’s construction date (Tier I, Tier II, Tier III).

Tier I: Marine diesel engines installed on ships constructed on or after 1 January 2000 but before 1 January 2011.

Tier II: Marine diesel engines installed on ships constructed on or after 1 January 2011. (Lower NOx limits than Tier I).

Tier III: Marine diesel engines installed on ships constructed on or after 1 January 2016 operating in designated NOx Emission Control Areas (NECAs), or on or after 1 January 2021 for specific NECAs like the North Sea and Baltic Sea. Tier III requires approximately an 80% reduction in NOx compared to Tier I.

Compliance Methods for Tier III (in NECAs):

Selective Catalytic Reduction (SCR) systems.

Exhaust Gas Recirculation (EGR).

Use of alternative fuels like LNG.

Engine International Air Pollution Prevention (EIAPP) Certificate: Engines subject to NOx limits must be certified and issued with an EIAPP Certificate and a Technical File.

3. Ozone Depleting Substances (ODS):

Prohibition: Deliberate emissions of ODS are prohibited. This includes substances like Halons and Chlorofluorocarbons (CFCs).

New Installations: New installations containing ODS are prohibited on all ships, except for permanently sealed equipment with minimal ODS charge (e.g., some domestic refrigerators). Hydrochlorofluorocarbons (HCFCs) are being phased out.

Record Keeping: An ODS Record Book must be maintained to log all operations involving ODS, such as recharging, repair, or disposal of equipment containing ODS.

4. Volatile Organic Compounds (VOCs):

While more relevant to tankers carrying crude oil or petroleum products, some bulk cargoes might emit VOCs.

Ships may be required to have a VOC Management Plan if they are subject to VOC emission controls in specific ports or terminals. For most bulk carriers, this is less of a primary concern unless carrying specific cargoes.

5. Shipboard Incinerators:

Shipboard incinerators installed after 1 January 2000 must be type-approved and meet specific emission standards outlined in Annex VI.

Prohibited Incineration: Certain materials are prohibited from being incinerated onboard, including:

Annex I, II, and III cargo residues and related contaminated packing materials.

Polychlorinated Biphenyls (PCBs).

Garbage containing more than traces of heavy metals.

Refined petroleum products containing halogen compounds.

Sewage sludge and sludge oil are not to be incinerated in the main propulsion machinery or boilers during port stays, unless specific conditions are met.

Operational Requirements: Incineration must be carefully managed, and records kept.

6. Energy Efficiency Regulations (Chapter 4 of Annex VI): This is a critical area for bulk carriers, aimed at reducing greenhouse gas (GHG) emissions.

Energy Efficiency Design Index (EEDI):

Applicability: Mandatory for new ships (bulk carriers, tankers, gas carriers, etc.) over 400 GT, with keel laid on or after 1 January 2013.

Requirement: The attained EEDI (a measure of a ship’s CO2 emissions per transport work) must be below a required EEDI, which becomes progressively stricter over time (Phase 0, 1, 2, 3).

Verification: EEDI is verified at the design stage and at sea trials.

Energy Efficiency Existing Ship Index (EEXI):

Applicability: Mandatory for existing ships (bulk carriers, etc.) over 400 GT, requiring verification by the first annual, intermediate, or renewal survey after 1 January 2023.

Requirement: The attained EEXI must be below a required EEXI. If not, technical modifications (e.g., engine power limitation – EPL, shaft power limitation – SHAPOLI, energy saving devices) may be needed.

Ship Energy Efficiency Management Plan (SEEMP):

Applicability: Mandatory for all ships of 400 GT and above.

Purpose: A ship-specific plan to improve energy efficiency in a cost-effective manner. It outlines measures for improving operational efficiency (e.g., voyage planning, speed optimization, hull maintenance, machinery optimization).

SEEMP Part I: Covers general energy efficiency measures.

SEEMP Part II (Data Collection Plan for Fuel Oil Consumption): Required for ships of 5,000 GT and above to collect and report fuel oil consumption data to their Flag State (IMO Data Collection System – DCS).

SEEMP Part III (Carbon Intensity Indicator – CII): Required for ships of 5,000 GT and above. This part outlines how the ship will achieve its required annual operational Carbon Intensity Indicator (CII) and includes a plan of corrective actions if the CII rating is D for 3 consecutive years or E for 1 year.

Carbon Intensity Indicator (CII):

Applicability: Ships of 5,000 GT and above.

Rating: Ships are rated annually (A, B, C, D, or E) based on their operational carbon intensity.

Corrective Actions: Ships rated D for three consecutive years or E for one year must develop a plan of corrective actions to achieve the required CII (C or above), which must be included in SEEMP Part III.

7. Surveys and Certification:

International Air Pollution Prevention (IAPP) Certificate: Ships of 400 GT and above must be surveyed and issued an IAPP Certificate.

International Energy Efficiency (IEE) Certificate: Required for ships of 400 GT and above, demonstrating compliance with EEDI (for new ships) and SEEMP requirements.

EIAPP Certificate: For marine diesel engines over 130 kW.

Statement of Compliance for Fuel Oil Consumption Reporting (IMO DCS): Issued after verification of reported data.

Statement of Compliance for CII: Issued after verification of the calculated CII.

8. Record Keeping:

Bunker Delivery Notes (BDNs): Retain for 3 years.

Fuel Oil Changeover Records: When operating in and out of ECAs.

EGCS Records: If scrubbers are used (monitoring data, sludge disposal).

ODS Record Book.

Incinerator Operation Records.

SEEMP and associated records (fuel consumption data, CII calculations, corrective action plans).

Records of Engine Parameters (for NOx compliance).

Best Practices for Bulk Carriers:

Fuel Management: Implement robust fuel procurement and management strategies, ensuring compliant fuel is used. If using scrubbers, ensure efficient operation and maintenance.

Energy Efficiency Measures: Actively implement measures identified in the SEEMP, such as:

Optimized voyage planning and weather routing.

Speed optimization.

Trim and ballast optimization.

Regular hull and propeller cleaning.

Main and auxiliary engine performance monitoring and maintenance.

Utilization of waste heat recovery systems.

Crew training on energy-efficient operations.

Stay Updated: Air pollution regulations are constantly evolving. Stay informed about new requirements and amendments.

Technology Adoption: Consider investing in energy-saving devices and technologies that can improve EEDI, EEXI, and CII ratings.

Data Analysis: Utilize collected fuel consumption data (IMO DCS) to identify trends and areas for further efficiency improvements.

Compliance with MARPOL Annex VI is complex and requires significant attention from ship operators, Masters, and crew. It plays a crucial role in mitigating the shipping industry’s impact on air quality and climate change. For bulk carriers, optimizing energy efficiency is not only an environmental imperative but also a key factor in maintaining commercial viability in a tightening regulatory landscape.