Book to sail on one of cruise and ferry operator Viking Line’s two LNG dual-fuelled ropax vessels, which ply between Sweden and Finland, and there is an option to decarbonise the trip by paying the company extra to load some of its bunkers as bio-LNG or liquefied biogas (LBG).

Viking Line vice president and director of freight Harri Tamminen told TradeWinds that the company set out with a promise to passengers whereby paying for LBG would cut the greenhouse gas emissions for their trip by 90% compared with a journey where just LNG was used.