Methanol Superstorage in cruise ship retrofit plans

2024-03-27T19:54:15+00:00 March 27th, 2024|Technology|

Cruise industry shipowners and operators have been in the vanguard of the alternative fuel movement, but commercial shipping led 2023’s charge to methanol.

Now, space-efficient ‘Methanol Superstorage’ is putting new energy into key cruise ship retrofits to replace conventional fuels.

Methanol-capable engines were a stand-out feature of the 2023 orderbook for commercial ships, as leading players in container transport threw their investment behind an alternative fuel whose ‘green’ version can one day run vessels emissions-free.

DNV said that methanol was “the most popular alternative fuel choice in 2023” by a small margin, with 138 ships ordered to feature methanol-capable dual fuel engines, compared to 35 in 2022. Containerships accounted for 106 vessels.

For the first time, methanol ship orders overtook LNG as an alternative to fuel oil.

Stakeholders in the cruise industry have long been open to the attractions of the methanol alternative, buying into a fuel which is already widely used by other industries as derived from natural gas, but could be recovered from renewable sources.

For example, MSC Group, Norwegian Cruise Line Holdings and Royal Caribbean Group are members of The Methanol Institute grouping.

Owners seeking practical pathways towards IMO and EU targets for de-carbonisation have been persuaded by methanol’s availability, predictability and relative ease of handling.

However, beyond the lack of bunkering infrastructure that stands in the way of rapid adoption of alternatives to HFO, the methanol road map features a shipboard storage challenge, which undermines conventional ship operating cost models. Tonne for tonne, methanol is almost two and a half times more space hungry than HFO in terms of energy efficiency.

Cruise shipping’s main players have therefore been quick to respond to Lloyd’s Register’s (LR) Approval in Principle (AiP) for ‘Methanol Superstorage’ – a new approach to storage tank construction, which developer SRC Group claimed increased volume by 85% over conventional solutions.

Conventionally, tanks storing low flashpoint fuels on board ship require cofferdams of at least 600 mm across to separate internal and external walls as a safety precaution. Instead, Methanol Superstorage features 25 mm thick tank walls, which are formed by sandwich panel system (SPS) technology.

Applicable to both newbuildings and retrofits, the Methanol Superstorage solution can be installed with only a minimal impact on the general arrangement of the vessel.

SPS technology consists of a patent protected continuous polymer core that has been injected between two steel surfaces. The steel polymer steel barrier has been used in maritime and offshore applications for over two decades, and has been approved for permanent repairs by all major IACS class societies, including for corrosion in ship structures.

Class approvals have also involved laboratory testing of the polymer core material for chemical resistance – including for methanol.

With all of the leading cruise lines already considering retrofitting their ships for methanol as a marine fuel, Hannes Lilp, SRC Group, CEO said that the specialist engineering, procurement, construction and installation company (EPCI) has quickly been involved in talks.

“These are confidential discussions, but the projects that have been progressing are now under review to accommodate consideration of Methanol Superstorage, while one project that looked totally dead is being revived,” Lilp explained.

Securing an AiP confirms that there are no major obstacles to future certification or classification, allowing a developer to “gain early confidence that your technology has the potential to satisfy regulatory requirements” LR said. It means “stakeholders will have confidence in their investment”.

Alex Vainokivi, Innovation Manager, SRC Group, acknowledged that the regulations underlying fuel storage are still evolving.

“The journey from AiP to full class approval is also substantive,” he observes.

“Due to the regulatory status of low flash point fuels, methanol fuelled ships need to go through a risk based certification process that includes the whole fuel system – from bunkering station to the engines.”

One argument for Methanol Superstorage’s case rests on its equivalent protection against fire or leakage to a conventional tank, he added. The injected polymer also creates oxygen-free conditions behind the steel plates to prevent corrosion.

“Under fire testing, SPS technology satisfies the fire safety objectives and the functional requirements of SOLAS A-60 regulations without the need to install thermal insulation,” Vainokivi said.

“What’s also been new since we secured AiP for Methanol Superstorage has been that the major engine makers have been contacting us too, while shipbuilders in Europe and Asia have been in touch with detailed, but often similar, enquiries,” he added.