The shipping industry has access to several biofuel options that can significantly reduce greenhouse gas emissions. The primary biofuels available include Fatty Acid Methyl Esters (FAME), Hydrotreated Vegetable Oil (HVO), biomethanol, bio-LNG (bio-liquefied natural gas), biomass-to-liquid (BTL) products, and straight vegetable oil (SVO). These fuels can be used in concentrations ranging from blends with conventional marine fuels to 100% pure biofuel, depending on the fuel type and vessel capabilities.
Understanding Marine Biofuel Options
FAME (Fatty Acid Methyl Esters)
FAME is produced through the transesterification of vegetable oils or animal fats and represents one of the most widely used biofuels in marine applications. This biodiesel variant can be blended with both distillate fuels (MGO/MDO) and residual fuels (HFO).
Key Specifications:
- Density: 885 kg/m³ at 20°C
- Viscosity: 3-5 mm²/s at 40°C
- Heating Value: 37-37.1 MJ/kg
- Cetane Number: Approximately 56
- Oxygen Content: 10-11%
Operational Considerations:
FAME blends are currently limited to 7% by volume under ISO 8217:2017 standards, though higher blends are possible with special considerations. The fuel absorbs water and is susceptible to oxidation and microbial growth, requiring careful handling and storage. Material compatibility issues may arise with certain elastomers and rubber components, and cold-temperature performance can be affected by cloud point characteristics.
HVO (Hydrotreated Vegetable Oil)
HVO represents a premium biofuel option produced through hydrotreatment and hydrocracking processes, resulting in a paraffinic renewable fuel with properties similar to conventional diesel.
Key Specifications:
- Density: 780 kg/m³ at 20°C
- Viscosity: 2-3 mm²/s at 40°C
- Heating Value: 43-44.1 MJ/kg
- Cetane Number: 80-99
- Oxygen Content: 0%
- Aromatics: 0%
- Sulfur: 0%
Operational Advantages:
HVO functions as a near drop-in replacement for conventional diesel with no significant operational or safety challenges. It can be used up to 100% concentration in marine diesel engines without modification, offering superior combustion properties and lower emissions compared to both FAME and conventional fuels.
Biomethanol
Biomethanol is produced from renewable biomass sources including agricultural residues, forestry waste, or biogas through gasification or fermentation processes.
Performance Characteristics:
Biomethanol can reduce tank-to-wake CO₂ emissions by up to 95% compared to conventional bunker fuels, with average reductions of 70-80% when produced from plant biomass. As a liquid at room temperature, it offers easier storage and bunkering compared to gas-based fuels.
Infrastructure and Adoption:
Both new builds and retrofitted engines can utilize methanol, with notable implementations including the Stena Germanica ferry and Maersk’s new methanol-powered fleet. Infrastructure is expanding particularly in Northern Europe and Asia, though biomethanol remains more expensive than conventional fuels and bio-LNG.
Bio-LNG (Bio-Liquefied Natural Gas)
Bio-LNG is produced by liquefying biomethane derived from biogas, primarily sourced from organic waste or energy crops.
Environmental Benefits:
Bio-LNG can achieve near-zero greenhouse gas emissions when produced from organic waste and may be considered carbon-negative when combined with carbon capture technologies.
Economic and Infrastructure Advantages:
Currently one of the cheapest sustainable marine fuels available, bio-LNG is compatible with existing LNG infrastructure, engines, and dual-fuel vessels. It can be blended with fossil LNG, enabling a gradual transition while meeting regulatory targets for IMO 2030 and 2050.
Supply Limitations:
Despite cost advantages, supply remains limited, and even with aggressive blending strategies, bio-LNG is expected to meet only a portion of future shipping demand without significant expansion into synthetic e-LNG production.
Additional Biofuel Options
Biomass-to-Liquid (BTL) Products:
These synthetic fuels are produced through thermochemical conversion of biomass, offering high-quality fuel characteristics suitable for marine applications.
Straight Vegetable Oil (SVO):
While less common in modern shipping, SVO can be used in certain engine configurations, though it typically requires engine modifications or heating systems.
Regulatory Framework and Standards
International Maritime Organization (IMO) Requirements
The IMO has established comprehensive regulations governing marine biofuel use as part of its strategy to achieve net-zero emissions by 2050.
2024 IMO Guidelines on Life Cycle GHG Intensity:
These guidelines mandate lifecycle assessment (well-to-wake) of greenhouse gas emissions for all marine fuels, including biofuels. They introduce a Fuel Lifecycle Label to verify emission factors and require biofuels to demonstrate substantial GHG reductions compared to fossil fuels through recognized certification schemes.
MARPOL Annex VI Regulations:
Biofuel use is governed under fuel quality requirements, with interim IMO guidance allowing blends up to 30% by volume. All biofuels must meet safety requirements including flashpoint and sulfur content limits consistent with SOLAS and MARPOL standards.
Blending Mandates:
IMO regulations for 2028 require ships to use approximately 17.6% to 23.3% biofuel (B100) blends to comply with carbon intensity targets. These requirements increase significantly by 2035, reaching up to 65% biofuel blending.
Quality Standards
ISO 8217:
This international marine fuel standard defines critical parameters including viscosity, flash point, sulfur content, and density for bio-blends. The 2024 revision specifically addresses bio-distillate and bio-residual marine fuels, recognizing that properties vary based on blend type and ratio.
EN 14214/ASTM D6751:
FAME used for blending must comply with these biodiesel quality standards to ensure consistent performance and safety.
Procurement Considerations
Supply and Availability
Global sustainable biomass availability is projected to grow from approximately 1.8 billion tons in 2025 to 3.3 billion tons by 2050. However, current supply remains limited relative to demand, driven by regulatory pressures including the EU’s FuelEU Maritime regulations.
Competition with Other Sectors
The aviation industry represents significant competition for biofuel resources, potentially consuming substantial portions of available biofuel production. This inter-sector competition necessitates strategic procurement planning and diversification of fuel sources.
Documentation and Certification
Procurement requires comprehensive documentation including:
- Bunker Delivery Notes
- Safety Data Sheets
- Sustainability certification from recognized schemes
- Lifecycle GHG emission verification
- Cost Considerations
Biofuel pricing varies significantly by type:
- Bio-LNG: Currently the most cost-effective sustainable option
- HVO: Premium pricing reflecting superior properties
- FAME: Moderate pricing but with operational limitations
- Biomethanol: Higher cost than bio-LNG and conventional fuels
Operational Implementation
Engine Compatibility
FAME Blends:
Require engine manufacturer approval for blends exceeding 7%. Risk assessments and potential fuel system modifications may be necessary for higher concentrations.
HVO:
Can be used up to 100% without engine modifications, offering the most straightforward implementation pathway.
Biomethanol and Bio-LNG:
Require dual-fuel capable engines or dedicated fuel systems, typically implemented in new builds or major retrofits.
Fuel Management
Onboard fuel management systems may require adjustments for:
- Viscosity and temperature settings due to different fuel properties
- Fuel stability monitoring, particularly for FAME blends
- Water contamination prevention
- Oxidation and microbial growth control
Safety Protocols
Compliance with the IMO’s ISM Code requires:
- Proper crew training on biofuel handling
- Updated safety procedures
- Regular fuel quality testing
- Material compatibility verification
- Market Outlook and Strategic Implications
Decarbonization Pathway
Biofuels offer an immediate and practical pathway for shipowners to reduce emissions without requiring extensive infrastructure modifications. They play a critical role in the shipping industry’s decarbonization journey, particularly during the transition period before alternative zero-emission technologies achieve commercial scale.
Holistic Approach
Industry experts emphasize that no single biofuel will meet all shipping needs. A holistic approach combining bio-based fuels, synthetic e-fuels, and operational efficiency improvements will be necessary to achieve net-zero targets.
Regional Variations
Biofuel availability and infrastructure development vary significantly by region:
- Northern Europe: Advanced biomethanol and bio-LNG infrastructure
- Asia: Expanding methanol bunkering capabilities
- Other regions: Varying levels of development requiring strategic planning
Key Takeaways
Diverse Fuel Portfolio:
The shipping industry has access to multiple biofuel options including FAME, HVO, biomethanol, bio-LNG, BTL products, and SVO, each with distinct characteristics and applications.
HVO Advantages:
HVO emerges as the premium drop-in solution, usable at 100% concentration without engine modifications, offering superior combustion properties and zero sulfur or aromatics.
Regulatory Compliance:
IMO regulations mandate increasing biofuel blending percentages, from 17.6-23.3% by 2028 to up to 65% by 2035, with comprehensive lifecycle GHG assessment requirements.
Supply Constraints:
While global biomass availability is projected to grow from 1.8 billion tons in 2025 to 3.3 billion tons by 2050, current supply remains limited with significant competition from aviation and other sectors.
Cost Spectrum:
Bio-LNG currently offers the most cost-effective sustainable option, while biomethanol commands premium pricing, requiring careful economic analysis for procurement decisions.
Infrastructure Compatibility:
Bio-LNG leverages existing LNG infrastructure, while biomethanol requires dedicated systems but offers easier handling than cryogenic fuels.
Quality Standards:
ISO 8217:2024 governs bio-blend specifications, with mandatory pre-use testing and sustainability certification through recognized schemes.
Operational Flexibility:
Different biofuels suit different vessel types and operational profiles, from FAME blends for gradual transition to HVO for immediate high-percentage implementation.
Strategic Planning:
Successful biofuel adoption requires comprehensive consideration of fuel properties, regulatory compliance, supply chain logistics, cost implications, and vessel-specific operational requirements.
Frequently Asked Questions
What is the difference between FAME and HVO biofuels?
FAME (Fatty Acid Methyl Esters) is produced through transesterification of vegetable oils or animal fats and contains oxygen (10-11%), making it susceptible to water absorption and oxidation. HVO (Hydrotreated Vegetable Oil) is produced through hydrotreatment and contains no oxygen, aromatics, or sulfur, offering superior combustion properties. HVO can be used at 100% concentration without engine modifications, while FAME is typically limited to 7% blends under current ISO standards.
Can biofuels be used in existing ship engines?
Yes, most biofuels can be used in existing engines, though requirements vary by fuel type. HVO can be used up to 100% without modifications, while FAME blends up to 7% are generally compatible with standard engines. Higher FAME concentrations and alternative fuels like biomethanol or bio-LNG may require engine manufacturer approval, fuel system modifications, or dual-fuel capable engines.
What are the emission reduction benefits of marine biofuels?
Emission reductions vary by biofuel type. Biomethanol can reduce tank-to-wake CO₂ emissions by up to 95% compared to conventional bunker fuels, with typical reductions of 70-80% from plant biomass sources. Bio-LNG can achieve near-zero greenhouse gas emissions when produced from organic waste and may be carbon-negative with carbon capture. All biofuels must demonstrate substantial GHG reductions through lifecycle assessment to meet IMO requirements.
What regulations govern the use of biofuels in shipping?
The IMO has established comprehensive regulations including the 2024 Guidelines on Life Cycle GHG Intensity requiring lifecycle emissions assessment for all marine fuels. MARPOL Annex VI governs fuel quality requirements, allowing blends up to 30% by volume under interim guidance. IMO regulations for 2028 require 17.6-23.3% biofuel blending, increasing to 65% by 2035. All biofuels must meet ISO 8217 standards and comply with safety requirements including flashpoint and sulfur limits.
What are the main challenges in procuring marine biofuels?
Key procurement challenges include limited supply despite growing demand, with global sustainable biomass availability expected to grow from 1.8 billion tons in 2025 to 3.3 billion tons by 2050. Competition with aviation and other sectors for biomass resources creates additional constraints. Shipowners must navigate complex multi-layered regulations including IMO’s Carbon Intensity Indicator, EU ETS, and FuelEU Maritime requirements. Cost premiums compared to conventional fuels, particularly for biomethanol and HVO, require careful economic analysis. Comprehensive documentation including sustainability certification, bunker delivery notes, and lifecycle GHG verification is essential.