The Environmental Impact of Liquefied Natural Gas (LNG) as a Marine Fuel

Cruise operators are promoting the use of liquefied natural gas (LNG) as a greener alternative to traditional marine fuels, but an investigation by environmental activists suggests that this shift may have adverse effects in the short term. While LNG-powered ships emit approximately 25% less carbon dioxide than ships using oil-based fuel, these vessels often fail to fully combust the gas, resulting in leaks of methane directly into the atmosphere. Methane, the primary component of LNG, has a global warming potential 80 times higher than CO2 during its first two decades in the atmosphere.

A certified thermographer employed by non-profit organization Transport & Environment used a special camera to capture footage of a cruise ship emitting large hydrocarbon plumes in Barcelona. An independent analysis of the footage suggests that the emissions from the ship, named MSC World Europa, likely contain methane. MSC Cruises, the Switzerland-based company that operates the vessel, claims that its engines have a lower methane leakage rate than the commonly cited 3.1% and will begin direct measurements later this year.

The International Maritime Organization recently set new emissions reduction goals that experts argue are inadequate for limiting global warming to 1.5°C. To truly transition towards a greener future, campaigner Constance Dijkstra from Transport & Environment argues that cruise operators should utilize engines capable of running on renewable energy-based fuels like hydrogen or ammonia. However, decarbonizing the shipping industry poses challenges, as there are currently limited clean alternatives to hydrocarbon-based fuels.

LNG-powered ships are touted as using the cleanest marine fuel available at scale today, as they emit lower levels of CO2, sulphur, nitric oxide, and nitrogen dioxide. However, with increased attention on the contribution of methane to climate change, the leaks of this potent greenhouse gas from LNG-powered ships are under scrutiny. Engine manufacturers are working on technologies to minimize methane leakage. MAN Energy Solutions, for example, plans to deliver its first ammonia engine for commercial marine transport by 2026. The availability of green e-fuels and the readiness of investors, regulators, and shipping companies remain crucial factors in transitioning the shipping industry to cleaner alternatives.

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