Icon of the Seas, the world’s largest cruise ship, embarked on its maiden voyage from Miami, but concerns have been raised by environmental groups regarding potential methane emissions from its liquefied natural gas (LNG) engines. The ship, owned by Royal Caribbean International, can accommodate 8,000 passengers across 20 decks, reflecting the growing popularity of cruises.
While LNG is considered a cleaner alternative to traditional marine fuel, environmentalists argue that the ship’s engines may release harmful methane into the atmosphere during the combustion process, known as “methane slip.” Methane is a potent greenhouse gas, with warming effects 80 times worse than carbon dioxide over a 20-year period.
Bryan Comer, Director of the Marine Program at the International Council on Clean Transportation (ICCT), expressed concerns about the environmental impact of using LNG as a marine fuel. He estimated that LNG could emit over 120% more life-cycle greenhouse gas emissions than marine gas oil.
Royal Caribbean contends that its new ship is 24% more efficient in terms of carbon emissions than the requirements set by the International Maritime Organization (IMO), the global shipping regulator. The company emphasizes the environmental advantages of LNG over very low sulfur fuel oil (VLSFO), which powers most of the global shipping fleet.
Critics argue that the estimated methane slip from cruise ship engines is higher than the IMO assumptions, with an average of 6.4% compared to the IMO’s assumed 3.5%. As the maritime industry increasingly adopts LNG, concerns about methane emissions have prompted closer scrutiny. The IMO has acknowledged the need to address methane emissions as part of its efforts to reduce greenhouse gases.
The cruise industry is witnessing a shift toward LNG-powered ships, with 63% of the 54 ships on order from January 2024 to December 2028 expected to be fueled by LNG, according to the Cruise Line International Association. However, environmental advocates emphasize the importance of continued efforts to reduce methane emissions and explore alternative, cleaner fuel options.
