Blog:
IMO 2025 GHG Goals: Short-Term, Mid-Term, and Long-Term Strategies for Shipping Decarbonization – A Chief Engineer’s Guide
Introduction
The maritime industry, responsible for over 80% of global trade, is a critical pillar of the world economy but also contributes approximately 3% of global greenhouse gas (GHG) emissions, totaling over 1 billion tons annually. The International Maritime Organization (IMO), as the United Nations’ regulatory body for shipping, has set ambitious targets to decarbonize the sector under its 2023 Revised Greenhouse Gas Emissions Strategy, adopted at the 80th Marine Environment Protection Committee (MEPC 80) meeting in July 2023. These targets, aligned with the Paris Agreement, aim to reduce GHG emissions through short-term (by 2030), mid-term (by 2040), and long-term (by 2050) measures, culminating in net-zero emissions by or around 2050. For chief engineers, these goals present both challenges and opportunities, requiring technical expertise, operational adjustments, and strategic planning to ensure compliance on vessels like container ships, LNG carriers, and bulk carriers. This blog provides a detailed exploration of the IMO’s 2025-focused GHG goals, their implications for ship operations, and a step-by-step guide for chief engineers to implement these measures effectively. Drawing from real-world examples, regulatory insights, and practical maintenance tips, this guide empowers maritime professionals to navigate the transition to a decarbonized future. For students and engineers seeking exam-specific insights, consider our eBook for tailored answers to maritime engineering challenges!
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IMO’s 2025 GHG Strategy: A Three-Tiered Approach
The 2023 IMO GHG Strategy replaces the 2018 Initial Strategy, introducing stricter targets and a life-cycle (well-to-wake) approach to account for emissions from fuel production to consumption. The strategy is a legally binding framework under MARPOL Annex VI, driving the maritime industry toward sustainability through clear timelines and measures. Below, we outline the short-term, mid-, and long-term goals, their relevance to ships, and the chief engineer’s role in achieving them.
2020–2030: Short-Term Goals
Objectives:
• Reduce total annual GHG emissions from international shipping by at least 20%, striving for 30%, by 2030 compared to 2008 levels.
• Achieve at least 40% reduction in carbon intensity (CO2 emissions per transport work) by 2030, pursuing efforts toward 70% by 2050, compared to 2008.
• Ensure at least 5–10% of maritime energy use comes from zero or near-zero GHG emission fuels (e.g., green methanol, biofuels) by 2030.
• Enhance energy efficiency through measures like the Energy Efficiency Existing Ship Index (EEXI) and Carbon Intensity Indicator (CII), effective since January 1, 2023.,
Relevance to Ships:
• EEXI: Applies to ships of 400 GT and above, requiring a one-time calculation to meet a ship-type-specific energy efficiency standard equivalent to EEDI Phase II or III for new ships. For example, a 2015-built Panamax container ship must reduce engine power or adopt technologies like shaft generators to comply.
• CII: Targets ships of 5,000 GT and above, rating them annually (A to E) based on CO2 emissions per cargo-carrying capacity and distance traveled. A 2020-built LNG carrier with a CII rating of D or E must implement corrective actions to achieve C or better.
• Fuel Transition: Ships must begin adopting low-carbon fuels. For instance, Maersk’s methanol-fueled container ships and Viking Line’s biofuel-powered ferries are early adopters.
• Operational Measures: Just-in-time (JIT) operations, as piloted by the IMO-industry Global Industry Alliance (GIA), reduce port waiting times, cutting emissions by 5–10% for bulk carriers and tankers.
Implementation Strategies for Chief Engineers:
• EEXI Compliance:
• Technical Modifications: Install engine power limitation (EPL) systems or shaft power limitation (ShaPoLi) to cap fuel consumption. For a 100,000 DWT bulk carrier, this might involve reducing main engine power by 10–20%.
• Retrofits: Consider energy-saving devices like air lubrication systems or propeller boss cap fins, which reduce fuel use by 3–7%. For example, a retrofit on a 2018-built VLCC saved 5% fuel, per DNV reports.
• Documentation: Maintain EEXI Technical File and Onboard Management Manual (OMM), logging all modifications and calculations for class society verification.
• CII Optimization:
• Operational Adjustments: Optimize speed and trim to improve CII ratings. A 10% speed reduction on a container ship can cut emissions by 15–20%, per ICCT studies.
• Fuel Monitoring: Use real-time fuel consumption sensors to track CII metrics, ensuring accurate reporting in the Ship Energy Efficiency Management Plan (SEEMP) Part III.
• Corrective Actions: For ships rated D or E, develop a Plan of Corrective Actions, such as hull cleaning or propeller polishing, to achieve a C rating. For instance, a 2019-built tanker improved its CII from D to B after hull maintenance.
• Low-Carbon Fuels:
• Biofuels: Test biofuels like HVO in existing diesel engines, ensuring compatibility per ISO 8217 standards. A trial on a 2021-built ferry reduced CO2 by 50%.
• Methanol Readiness: Prepare for methanol by inspecting fuel systems for corrosion-resistant materials (e.g., stainless steel). Maersk’s methanol ships use dual-fuel engines, requiring specific maintenance protocols.
• LNG Maintenance: For LNG-fueled ships, monitor methane slip using gas analyzers, aiming for <1% slip, as recommended by MAN Energy Solutions.
• JIT Operations:
• Coordinate with port authorities for JIT arrivals, using digital tools like the Maritime Single Window (mandatory since January 2024).
• Maintain auxiliary engines in standby mode to minimize idling emissions during port delays.
Maintenance Tips:
• Calibrate fuel flow meters and torque limiters monthly to ensure EEXI compliance.
• Inspect hull coatings for biofouling, scheduling drydock cleaning every 2–3 years to improve CII.
• Test biofuel quality for microbial growth, using centrifuge separation to prevent injector clogging.
• Update SEEMP Part III annually, logging CII ratings and corrective actions for audits.
Challenges:
• High retrofit costs ($1–5 million per ship for energy-saving devices).
• Limited biofuel availability, with global supply covering only 1–2% of shipping demand.
• Crew training gaps for new fuels, requiring STCW-aligned courses.
2030–2040: Mid-Term Goals
Objectives:
• Reduce total annual GHG emissions by at least 70%, striving for 80%, by 2040 compared to 2008 levels.
• Achieve a 90% reduction in GHG intensity for the average ship by 2040, accounting for trade growth.
• Implement mid-term measures, including a goal-based marine fuel standard (phasing in low-GHG fuels) and a global maritime GHG emissions pricing mechanism (e.g., carbon levy), to be adopted in October 2025 and effective by 2027.
• Expand zero-emission fuel use (e.g., green ammonia, hydrogen) to 20–30% of maritime energy by 2040.
Relevance to Ships:
• Fuel Standard: Ships must use fuels with progressively lower GHG intensity. For example, a 2025-built container ship may transition from LNG to green methanol or ammonia by 2035.
• GHG Pricing: A carbon levy ($150–300 per ton of CO2, per industry proposals) will incentivize low-carbon fuels. A 100,000 DWT tanker emitting 20,000 tons of CO2 annually could face $3–6 million in levies, pushing operators toward greener options.
• Technology
Adoption: Ships like Icon of the Seas (methanol-ready) or
• Retrofits: Existing fleets, such as 2010-built bulk carriers, may require major retrofits (e.g., ammonia engines) costing $15–25 million.
Implementation Strategies for Chief Engineers:
• Fuel Transition Planning:
• Methanol: Retrofit dual-fuel engines for methanol, ensuring corrosion-resistant fuel lines. Monitor combustion for NOx emissions, using selective catalytic reduction (SCR) systems.
• Ammonia: Prepare for ammonia by installing gas-tight engine rooms and toxic gas detectors, per forthcoming IMO guidelines. Test ammonia fuel systems in pilot projects, as MAN Energy Solutions plans for 2026.
• Hydrogen:
For short-sea vessels, maintain fuel cell stacks, checking membrane integrity
and cooling systems.
• GHG Pricing Compliance:
• Track well-to-wake emissions using IMO’s Life Cycle Assessment (LCA) Guidelines, reporting fuel consumption by type in the Data Collection System (DCS).
• Optimize fuel use to minimize levy costs, using AI-based route planning tools like Bearing’s engine.
• Maintain accurate Oil Record Books (ORBs) and DCS reports, as audits will intensify post-2027.
• Energy Efficiency Upgrades:
• Install
wind-assisted propulsion (e.g., rotor sails), reducing fuel use by 5–15% on
bulk carriers, as trialed by
• Adopt air lubrication systems, cutting drag by 5–10% on VLCCs, per Silverstream Technologies.
• Use digital twins to simulate engine performance, reducing emissions by 3–5%, as implemented by Naval Group.
• Crew Training:
• Enroll in IGF Code-compliant courses for ammonia and hydrogen handling, focusing on toxicity and flammability risks.
• Conduct drills for fuel leaks or pricing audits, updating SMS procedures.
Maintenance Tips:
• Inspect methanol tanks for corrosion, using ultrasonic testing every 6 months.
• Calibrate ammonia gas detectors and SCR systems, ensuring NOx emissions meet Tier III.
• Monitor hydrogen fuel cell coolant levels, replacing membranes per manufacturer schedules.
• Test rotor sails for structural integrity, scheduling maintenance during port calls.
• Log all retrofit data in the PMS, ensuring compliance with class society standards.
Challenges:
• Limited
bunkering for ammonia and hydrogen, with only pilot facilities in
• High fuel costs (green ammonia is 3–5x HFO) and retrofit expenses.
• Regulatory uncertainty until mid-term measures are finalized in 2025.
2040–2050: Long-Term Goals
Objectives:
• Achieve net-zero GHG emissions by or around 2050, with efforts to phase out emissions entirely, consistent with the Paris Agreement’s 1.5°C goal.
• Ensure 100% of maritime energy comes from zero-carbon fuels or technologies (e.g., green ammonia, e-methanol, hydrogen fuel cells).
• Maintain a just and equitable transition, supporting developing countries, least developed countries (LDCs), and small island developing states (SIDS) through capacity building and funding.
Relevance to Ships:
• Zero-Carbon Fuels: Newbuilds, like ammonia-fueled LNG carriers planned for 2030, will dominate. Existing ships, such as 2020-built container ships, may be scrapped or retrofitted for zero-carbon fuels.
• Electrification: Fully electric or hybrid ships, like Estay’s battery-powered tugs, will serve short-sea routes.
• Autonomous
Vessels: Autonomous ships, such as
• Global Standards: The IMO Net-Zero Framework, effective from 2027, will enforce universal compliance, impacting fleets like Maersk’s 400-vessel network.
Implementation Strategies for Chief Engineers:
• Zero-Carbon Fuel Systems:
• Ammonia Engines: Maintain ammonia engines, focusing on fuel injectors and combustion chambers to prevent NOx formation. Pilot projects, like those by Wärtsilä, guide maintenance protocols.
• Hydrogen Fuel Cells: Monitor fuel cell efficiency, replacing stacks every 5–7 years. Ensure hydrogen purity to avoid contamination, as seen in Hylron’s prototypes.
• E-Methanol: Adapt engines for e-methanol, ensuring compatibility with LCA Guidelines for well-to-wake reporting.
• Electrification and Hybrids:
• Maintain battery systems, checking charge cycles and thermal management. For example, a hybrid ferry’s lithium-ion batteries require cooling system checks biweekly.
• Install shore power connections (cold ironing), reducing emissions in ports, as mandated by EU regulations.
• Autonomous Systems:
• Manage AI navigation systems, calibrating radar and LIDAR sensors monthly.
• Update cybersecurity protocols to protect autonomous controls, per CYDOME’s recommendations.
• Train crew on manual overrides, ensuring SMS compliance.
•
• Participate in IMO’s GreenVoyage2050 Programme, accessing training for LDCs and SIDS on zero-carbon technologies.
• Collaborate with ports for alternative fuel bunkering, using tools like the Maritime Single Window.
Maintenance Tips:
• Test ammonia fuel systems for leaks, using toxic gas detectors calibrated weekly.
• Monitor battery health with diagnostic tools, replacing cells per manufacturer guidelines.
• Update AI software quarterly, ensuring compatibility with navigation systems.
• Maintain shore power connectors, checking insulation for wear.
• Log all zero-carbon fuel data in DCS and ORB, preparing for IMO audits.
Challenges:
• Scalability of zero-carbon fuel production, with green hydrogen supply covering <5% of demand by 2040.
• High costs for electrification ($10–20 million per ship) and autonomous retrofits.
• Ensuring equitable access to technology for developing nations.
Practical Considerations for Chief Engineers
Chief engineers play a pivotal role in implementing IMO’s GHG goals, bridging technical execution with regulatory compliance. Below are cross-cutting strategies to achieve these objectives across all timeframes:
• Regulatory Compliance:
• Documentation: Maintain accurate records in the SEEMP, ORB, and DCS, logging EEXI calculations, CII ratings, and fuel consumption. For example, a 2017-built tanker’s SEEMP Part III must detail CII corrective actions.
• Audits: Prepare for ISM audits, ensuring compliance with MARPOL Annex VI and IMO’s Net-Zero Framework. Use checklists to verify EEXI and CII documentation.
• Reporting: Submit DCS data annually, using LCA Guidelines for well-to-wake emissions. Ensure crew are trained on reporting protocols.
• Technology Integration:
• Predictive Maintenance: Use AI and IoT sensors (e.g., Eniram’s solutions) to predict equipment failures, reducing downtime by 20–30%. For instance, a 2022-built VLCC uses digital twins for engine optimization.
• 3D Printing: Adopt 3D printing for spare parts, reducing lead times for components like pump impellers on remote voyages.
• Advanced Materials: Use corrosion-resistant alloys and eco-friendly coatings to enhance hull efficiency, as seen on COSCO’s newbuilds.
• Crew Training and Safety:
• Enroll in STCW and IGF Code courses for alternative fuels, focusing on ammonia and hydrogen safety.
• Conduct regular drills for fuel leaks, blackouts, and autonomous system failures, updating SMS procedures.
• Foster a safety culture, encouraging crew to report near-misses, per IMO’s just transition principles.
• Collaboration and Innovation:
• Engage with IMO’s GreenVoyage2050 Programme for technical support, particularly for LDCs and SIDS.
• Partner with ports for JIT operations and alternative fuel bunkering, using digital platforms like the Maritime Single Window.
• Participate in pilot projects, such as those under the GloMEEP initiative, to test zero-carbon technologies.
Case Studies: Real-World Implementation
• Maersk’s Methanol-Fueled Fleet:
• Maersk’s 2024-launched methanol-fueled container ship reduces CO2 by 65% compared to HFO. Chief engineers maintain dual-fuel engines, monitoring corrosion and NOx emissions, aligning with mid-term goals.
• Lesson: Early adoption of green fuels requires robust maintenance and crew training.
• Yara Birkeland’s Autonomy:
•
• Lesson: Autonomous vessels demand cybersecurity and sensor maintenance expertise.
• COSCO’s Wind-Assisted Bulk Carrier:
• COSCO’s 2023-built bulk carrier uses rotor sails, cutting fuel use by 10%. Engineers inspect sail structures and optimize engine performance, contributing to CII compliance.
• Lesson: Hybrid technologies offer cost-effective emissions reductions.