LNG as marine fuel

A bridge to nowhere

Due to its significant contribution to air pollutant and greenhouse gas emissions, shipping plays a particularly important role in climate protection and air pollution control. Although maritime transport is considered a relatively energy-efficient mode of transport in terms of the volume of goods transported, it still accounts for around three percent of global greenhouse gas emissions. In addition, shipping contributes significantly to global air pollution: around ten percent of global emissions of nitrogen dioxide and sulfur dioxide are attributable to shipping, as is a significant proportion of Black Carbon and particulate matter emissions. 

Heavy fuel oil, which is primarily used as marine fuel today, but also higher-quality marine diesel, cause enormous climate and environmental pollution due to their exhaust gases and in the event of accidents. An alternative is essential if shipping, as the central means of transport in a globalized world economy, is to have an ecologically sustainable future. The use of LNG as a maritime fuel is being discussed as a possible solution, particularly in light of the global limits for sulfur and nitrogen oxides. However, the actual climate impact throughout the fuel's life cycle and existing technical problems have not been conclusively investigated and are not fully covered by existing regulations. A study commissioned by NABU provides the latest research findings.

Methane emissions as a climate killer

From a climate perspective, LNG has no place in shipping and should not play a role in achieving the goal of climate-neutral shipping by 2050. While LNG has been discussed as a fuel for shipping due to its low price and low air pollutant emissions, the unavoidable methane slip is a real climate killer. Methane has an 85 times greater short-term impact on the climate than CO2. This effect fundamentally worsens the climate balance of LNG and, according to a study by the International Council for Clean Transportation (ICCT), puts it on a level with heavy fuel oil and marine diesel. 

In the case of cruise ships in particular, the climate balance with LNG can actually be worse than with diesel, as the engines used here cause particularly high methane emissions. Due to the long service life of ships, a switch to LNG carries the risk of long-term lock-in effects for fossil natural gas. The argument that LNG serves as a “bridge technology” does not hold water, as it prevents investment in long-term sustainable solutions. Instead, increasing the attractiveness of more climate-friendly fuels, in particular hydrogen, ammonia, or methanol, would be crucial in order to produce them in sufficient quantities in the medium term. 

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