Study: Using LNG as Fuel Would Cut GHG Emissions by Up to 21%

Using LNG as marine fuel would reduce the shipping industry’s greenhouse gas emissions by up to 21%, according to a study conducted by SEALNG and Society for Gas as a Marine Fuel Limited (SGMF).

The percentage of GHG reduction is compared with current oil-based marine fuels over the entire life cycle from Well-to-Wake (WtW). The parties said that the benefit is highly dependent on the engine technology installed and, to a certain extent, on the type of reference fuel (distillate or residual).

The study also confirms that emissions of other local pollutants, such as sulphur oxides (SOx), nitrogen oxides (NOx) and particulate matter (PM), are close to zero when using LNG compared with current conventional oil-based marine fuels.

“The Life Cycle GHG Emission Study is a long-awaited piece of the ‘LNG as a marine fuel’ puzzle.  It not only confirms what we already knew in terms of LNG’s immediate impact on air quality, human health and its cleanliness, but clearly highlights the genuine, substantiated GHG benefits of using today’s marine engines capable of burning natural gas,” Peter Keller, SEALNG Chairman, said.

A large number of SEALNG and SGMF member companies submitted up-to-date, technical data providing the basis for a complete and accurate life cycle analysis of the GHG intensity expressed in terms of CO2-equivalents.

On an engine technology basis, the study showed that absolute WtW emissions reduction benefits for LNG-fuelled engines compared with HF-fuelled ships today are between 14% to 21% for 2-stroke slow speed engines and between 7% to 15% for 4-stroke medium speed engines. 72% of the marine fuel consumed today is by 2-stroke engines with a further 18% used by 4-stroke medium speed engines.

The study showed that LNG provides a significant advantage in terms of improving air quality which is particularly important in ports and coastal areas. Beyond the benefits associated with reducing air pollutants, the parties noted that LNG is a viable solution to reduce GHG emissions from international shipping and to contribute to the International Maritime Organization (IMO) GHG reduction targets.

Ongoing optimisation in supply chain and engine technology developments will further enhance the benefits of LNG as a marine fuel, the parties noted. Additionally, bioLNG and Synthetic LNG, both fully interchangeable with LNG derived from fossil feedstock, offer the potential for significant additional GHG emissions reductions. For example, a blend of 20% bioLNG as a drop-in fuel can reduce GHG emissions by a further 13% when compared to 100% fossil fuel LNG.

The international shipping industry is under pressure to cut emissions on the back of the IMO’s ambition to reduce the GHG emissions from international shipping by at least 50% by 2050 compared with 2008. More stringent air quality regulations, such as the IMO 2020 global sulphur cap, are also approaching. In the light of the IMO 2020 global sulphur cap, conventional oil-based residual marine fuels will need to either change in their specification or be replaced by alternative fuels like LNG, the parties concluded.