Barriers impede LPG as a marine fuel: Study

LPG combined with carbon capture technology could become a widespread alternative marine fuel if the technology is available to use it onboard and safety concerns are addressed, maritime classification society Lloyd's Register (LR) and industry group World Liquid Gas Association (WLGA) said Wednesday in a report.

LPG made from fossil fuel sources emit around 97pc less sulphur oxide emissions than conventional marine fuels, 20pc less nitrogen oxide emissions and about 20pc less carbon emissions, according to the study. This makes current LPG supply compliant with regulatory standards such as the 0.5pc sulphur cap regulation set by the UN's International Maritime Organization, LR and WLGA said.

While LPG carriers and very large gas carriers (VLGCs) increasingly can burn LPG as fuel, the technology needed to use LPG as an alternative marine fuel will need to be scaled up to use it on different types of ships as well as to meet the emission reduction goals of the maritime industry.

There is currently no four-stroke engine that can use LPG as a marine fuel, which would require an auxiliary engine with an additional fuel to boost its decarbonization, according to the study. German engine manufacturer Man Energy Solutions has built two-stroke engines for newbuild and retrofitted gas carriers.

A two-stroke engine completes a cycle of intake, compression, power, and exhaust in two strokes and a four-stroke engine does it in four. Two-stroke engines are typically used in ocean-going vessels such as bulk carriers and four-stroke engines are used in ships such as ferries.

Safety hazards for using LPG onboard are also a barrier to adopting it as a reliable alternative marine fuel. LPG mixed with air is a fire and explosion hazard if it is used and stored incorrectly. It is also toxic to inhale at high concentrations. Lastly, LPG in its liquid form could cause cold burns if the skin is not properly insulated, the study said.

There will need to be safeguards regarding ship design and construction, bunkering technology, and onboard procedures for the vessel's crew to mitigate the dangers for LPG as a marine fuel, LR and WLGA said.

By Luis Gronda