Eric Linsner, LNG Specialist, International Registries, Inc., USA, discusses the progress and challenges for the use of LNG as a marine fuel in small scale applications.
LNG as a marine fuel started to take off when the international community agreed that ships should reduce their emissions of sulfur oxides (SOx) and particulate matter into the atmosphere. Traditionally, large oceangoing ships use heavy fuel oils (HFO) with a sulfur content of 4.5% or higher. Combustion of sulfur in marine propulsion produces SOx, which in the presence of water produces sulfuric acid and results in acid rain, thus acidifying the oceans and damaging plant life. With the reduction of SOx emissions from land-based facilities, the world focused attention on the need for emissions reduction from the marine industry.
On 1 January 2020, the International Maritime Organization (IMO) – the United Nations specialised agency with responsibility for the safety and security of shipping and the prevention of marine pollution by ships – brought into force a new annex to the International Convention for the Prevention of Pollution from Ships (MARPOL). This new MARPOL regulation reduced the maximum allowable sulfur content for marine fuel to 0.5%, with even lower limits in designated emission control areas (ECA).
This dramatic reduction in sulfur content presented several technical and commercial challenges for the marine industry. Initially, there was concern over the global refining industry’s ability to produce enough low sulfur fuel oil (LSFO) to meet the MARPOL requirements and demand for the rapid transition of the world fleet to a new fuel specification. Although the availability of LSFO does not currently appear to be a significant issue, the problem of usage of off-specification fuel and other operational quality issues remain. Traditional HFO is the lowest cost fraction of the petroleum distillation process. Sulfur removal increases the cost of the fuel, creating commercial incentives to consider alternatives to LSFO.
