From a tank-to-wake perspective, even the use of green methanol fuel counts towards GHG emissions since methanol contains carbon, but it remains to be seen if onboard carbon capture and storage (CCS) is a viable solution to combine with it.

Even if green hydrogen is used to produce methanol, if the source of the carbon is based on fossil fuels, it is challenging to label the resulting methanol as truly clean, says Dr Song Kanghyun, Senior Vice President & Head of KR Decarbonization, Ship R&D Center at Korean Register. This is because carbon emissions from fossil fuels are released into the atmosphere during the methanol utilisation phase, which occurs after its synthesis. “However, when fossil fuel-based carbon is captured and processed by onboard CCS, it is believed that it can be considered clean methanol, equivalent to green methanol.”

Depending on the fuel used in the propulsion system, onboard CCS could be implemented in two ways: either the ship is propelled by methanol, or hydrogen produced by reforming methanol is used to power an internal combustion engine or fuel cell.