NYK Line has commenced a one-year trial involving the continuous use of 100% biofuel (B100) on one of its car carriers, in what the Japanese firm says is an effort to evaluate the fuel's effects on vessel equipment and verify operational safety under real-world conditions.

The trial, announced on 2 June, uses a biofuel primarily comprising fatty acid methyl ester (FAME) derived from used cooking oil and similar feedstocks. NYK said the initiative aims to accumulate technical expertise that could support the broader adoption of high-purity biofuels and contribute to reductions in greenhouse gas (GHG) emissions across its fleet.

Biofuels are regarded within the shipping industry as a promising drop-in fuel option, as they can be used with existing ship engines and infrastructure without requiring significant modifications. However, NYK notes that global experience with the long-term continuous use of B100 remains limited.

NYK has been expanding its use of biofuels in recent years. In 2024, the company conducted a trial using a B24 blend — a mixture of approximately 24% biofuel and conventional fuel oil — before extending practical usage to B30. The current trial represents a step further, moving to undiluted biofuel for an extended operational period.

The company highlighted that high-purity biofuels such as B100 are susceptible to degradation from oxygen, light, and heat, raising questions about fuel stability during prolonged use. Over the course of the one-year trial, NYK is to collect operational data on the impact of B100 on engines, fuel supply systems, and day-to-day operational practices.

NYK noted that biofuels offer the potential to reduce GHG emissions across the entire lifecycle — on a well-to-wake basis — compared with conventional fossil fuels. The company said it intends to build on findings from the trial to continue technical evaluations and advance efforts towards sustainable maritime transportation.