What Arctic Cruise Operators Need to Know

As the Arctic cruise industry accelerates its transition to low-carbon operations, biofuels have emerged as a promising, practical solution for reducing greenhouse gas (GHG) emissions. Each has unique properties, operational considerations, and implications for greenhouse gas (GHG) compliance. This article outlines the main types of marine biofuels— Straight Vegetable Oil (SVO), Fatty Acid Methyl Ester (FAME), and Hydrotreated Vegetable Oil (HVO)—compares their properties, and highlights operational considerations and regulatory requirements for expedition cruise operators in polar waters.

What Are They?

• SVO (Straight Vegetable Oil): Unprocessed or minimally processed vegetable oils (e.g., soybean, rapeseed, used cooking oil). SVO is the least refined and generally the cheapest, but lacks standardized quality controls and presents compatibility challenges with most marine engines ².
• FAME (Fatty Acid Methyl Ester): Commonly known as biodiesel, FAME is produced by transesterifying SVO or animal fats with methanol. It is most widely used in shipping due to favorable cost-quality balance and established standards (now up to 100% in ISO 8217:2024)^1,2.
• HVO (Hydrotreated Vegetable Oil): Also called renewable diesel, HVO is made by hydrogenating SVO or waste oils resulting in a paraffinic fuel chemically similar to fossil diesel. Its similarity to fossil marine gas oil (MGO), HVO is more expensive but offers superior stability and excellent drop-in compatibility and stability^1,2.

How Do They Compare?

What are the Key Operational and Technical Issues

• Compatibility: HVO is a true drop-in fuel, requiring minimal or no engine modifications. FAME can be used in most engines but may require material checks and maintenance adjustments. SVO is generally not recommended for modern marine engines without significant modifications^1,2.
• Stability and Storage: FAME and SVO are prone to oxidation and microbial growth, especially in cold, damp environments. Storage time should be minimized, and tanks must be kept dry and clean. HVO is much more stable^1,2.
• Cold Flow Properties: Both FAME and SVO can gel at low temperatures, posing a risk for Arctic operations. HVO performs better in cold climates but still requires monitoring of pour and cloud points^1,2.
• Material Compatibility: FAME and SVO can cause swelling or degradation of certain rubbers and elastomers in fuel systems. Use of resistant materials (e.g., fluorine rubbers) is recommended².
• Sludge and Cleaning Effect: FAME and SVO, due to their polarity, can dissolve old deposits in fuel tanks and lines, leading to filter clogging during the initial transition. Enhanced filtration and cleaning routines are advised^1,2.
• Fuel Quality: Only purchase biofuels from reputable suppliers and insist on compliance with ISO 8217:2024 and relevant EN standards. Off-spec fuels can cause severe operational issues^1,2.
• GHG Compliance: Only certified sustainable biofuels (e.g., ISCC, RSB) with at least 65% well-to-wake GHG savings over fossil MGO are eligible for regulatory benefits under IMO and EU rules^1,2.

What are the Potential Issues and Risks

• SVO: No quality standard, high risk of filter clogging, sludge, and engine deposits. Not widely recommended for marine engines without significant modifications2.
• FAME: Prone to oxidation (degradation), water absorption, microbial growth, and can cause swelling of rubber components. Requires careful tank cleaning, monitoring, and limited storage time^1,2.
• HVO: Best drop-in performance, but low lubricity may require additives. Higher cost and limited feedstock availability^1,2.

What are the Regulatory and Compliance Aspects

• Biofuels can significantly reduce well-to-wake GHG emissions and are recognized under IMO and EU regulations (CII, EU ETS, FuelEU Maritime), provided they meet sustainability and GHG reduction criteria (typically at least 65% GHG savings compared to fossil MGO) ^1,2.
• Documentation: Proof of Sustainability (PoS) from recognized certification schemes (e.g., ISCC, RSB) is required for compliance. Blends above 30% biofuel may require additional NOx compliance checks with engine manufacturers^1,2.

Biofuels, especially FAME and HVO, are increasingly available at major bunkering ports and are already in use by leading cruise and expedition operators. Their drop-in capability makes them a practical near-term solution for decarbonization, but careful planning and adherence to best practices are essential, especially in the challenging Arctic environment.