Methanol: the green option for subsea support vessels

NSK Ship Design manager of design Torgeir Torgersen explained methanol and batteries were selected for these Agalas vessels due to the storage and safety of methanol.

“IMR vessels need 30 days of fuel storage and cable layers should have 60 days operation,” Mr Torgersen said. The design of the green IMR vessel requires methanol to be stored in tanks in the stern and a fuel preparation room close to the engineroom, with specific air inlet and outlet facilities and safety zones.

For 30 days of operation, vessels need 600 m³ for marine gas oil (MGO) storage or 1,850 m³ for methanol stored at ambient pressures.

Fugro is planning to retrofit its vessels for methanol fuel, with batteries and hybrid propulsion as part of its strategy to become net-zero by 2035. It is converting survey and IMR vessel Fugro Pioneer to run on methanol and MGO, with new engines set to be installed in the Netherlands in December 2024.

Fugro fleet development manager Peter Toxopeüs explained how Fugro is using vessel optimisation and unmanned units to reduce emissions by 20% by 2025, while the strategy to decarbonise by 2035 will include battery hybrid and methanol fuels.

“It is very difficult to do this with the current fleet, but many of the vessels are less than 10 years old, so we aim to retrofit,” he said.

“Technology needs time to mature and we do not have the resources to do the whole fleet in one go, so we defined a roadmap with multiple streams to decarbonise.”

He said methanol is the only viable choice, as other green fuels have high safety risks, or require too much onboard storage to make them technically viable for Fugro’s ships and those it charters in from other owners.

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