Royal Caribbean International’s Icon of the Seas, the world’s largest cruise ship, is set for its maiden voyage, departing from Miami on Saturday. However, environmental groups are expressing concerns about potential harmful methane emissions from the liquefied natural gas (LNG)-powered vessel, as well as other giant cruise liners that may follow suit.
The Icon of the Seas, with a capacity for 8,000 passengers across 20 decks, reflects the growing popularity of cruises. While LNG is considered a cleaner alternative to traditional marine fuel, it poses a higher risk of methane emissions. Environmentalists argue that methane leakage from the ship’s engines presents an unacceptable climate risk due to its short-term harmful effects.
Bryan Comer, Director of the Marine Program at the International Council on Clean Transportation (ICCT), criticized the move, stating, “It’s a step in the wrong direction,” and estimating that using LNG as a marine fuel emits over 120% more life-cycle greenhouse gas emissions than marine gas oil.
Methane, despite having a shorter atmospheric lifespan than carbon dioxide, is 80 times more potent in terms of warming effects over a 20-year period. Cruise ships, like the Icon of the Seas, utilize low-pressure dual-fuel engines that release methane into the atmosphere during the combustion process, a phenomenon known as “methane slip.”
Royal Caribbean claims that its new ship is 24% more carbon emissions-efficient than required by the International Maritime Organization (IMO), the global shipping regulator.
While LNG emits fewer greenhouse gases than very low sulfur fuel oil (VLSFO), industry experts acknowledge the challenge of methane slip in cruise ship engines. Cruise ship engines are estimated to have a methane slip of 6.4% on average, according to 2024 research funded by the ICCT and other partners, while the IMO assumes methane slip at 3.5%.
With 63% of ships ordered between January 2024 and December 2028 expected to be powered by LNG, the Cruise Line International Association reveals that around 6% of the existing 300 cruise ships are currently fueled by LNG. Newer cruise ships are being designed to run on traditional marine gas oil, LNG, or alternatives like bio-LNG.
Royal Caribbean emphasized its commitment to adapting to evolving market trends, stating that LNG is one component of its overall environmental strategy. Source: Reuters
