Ships Using B100 Need 15% More Fuel to Match VLSFO Range

Wallem Group warns that biofuel’s lower energy density, moisture absorption, and fuel system challenges increase operational complexity. File Image / Pixabay

As the shipping industry adopts marine biofuel blends to reduce emissions and meet regulatory targets, Hong Kong-based maritime service provider Wallem Group has flagged concerns around biofuel blends.

Ships running on B100 (100% biofuel) may need about 10-15% more fuel to match the range of voyages powered by VLSFO, the firm said in a white paper on biofuels best practice published on Tuesday.

The issue stems from B100's lower energy density, meaning more volume is required for the same energy output.

This limits flexibility on long voyages, Wallem noted in its white paper, adding that vessels must carefully consider fuel tank capacity, segregation and changeover planning before switching.

Biofuels Bring Their Own Technical Challenges

Wallem Group argues that beyond volume concerns, marine biofuels also bring added complexity.

Fatty Acid Methyl Ester (FAME)-based blends — widely used in marine biofuel blending — are hygroscopic, meaning they absorb moisture from the air. This can encourage microbial growth, leading to sludge formation and clogged filters, posing risks to engine reliability and maintenance schedules.

Hydrotreated Vegetable Oil (HVO), though considered a cleaner biofuel, is less commonly used due to its higher cost. It also brings its own challenge: a higher cloud point, which increases the risk of wax formation in colder climates, potentially blocking filters and fuel lines.

Wallem Group says some container ships that trialled B100 faced issues like cold flow and filter clogging.

These issues are rarely encountered with VLSFO, which remains more stable, predictable, and easier to manage within existing shipboard fuel systems.

Biofuels can also degrade rubber seals, corrode metal components, and require more frequent maintenance, it argues.

While biofuels help lower GHG emissions, Wallem's findings highlight the operational trade-offs.

It says owners must assess the full impact, not just emissions, but storage, system compatibility and reliability.