Growing popularity of LNG as a fuel in maritime and land transport
Less than 1% of the world fleet is LNG-powered, but this figure is expected to grow at least fivefold over the coming years. Recent figures suggest that the use of liquefied natural gas (LNG) as a fuel for maritime and land transport could significantly reduce greenhouse gas emissions from transport.
According to a recent review article, the popularity of LNG as a fuel is on the rise. The technology is well developed, and the number of ships and vehicles fuelled by LNG is expected to grow. 
LNG as a maritime fuel
The International Marine Organization (IMO) aims at reducing the total greenhouse gas (GHG) emissions from international marine transport by at least 50% in 2050 compared to 2008. According to the Society for Gas as a Marine Fuel (SGMF), the use of LNG yields a reduction of GHG emissions by 7 to 21% compared to current oil-based marine fuels. 
The authors of the review article have noted that as of June 2020, there were about 200 LNG-powered vessels worldwide (excluding LNG carriers) and an equivalent number of confirmed orders for new vessels.  These figures represent less than 1% of the world fleet.  Nevertheless, the use of LNG as maritime fuel is expected to increase fivefold from 2018 to 2022, as larger vessels use LNG for propulsion. The authors suggest that in the future, at least several dozens of ships per year will be built or retrofitted to run with LNG. Indeed, they believe LNG to be a low-emission technology intermediate between conventional fuels (e.g. gasoline, diesel, LPG) and liquid hydrogen or ammonia. The latter fuels are expected to help achieve a conversion to zero emissions after 2030. 
LNG as a fuel for road transport 
The authors of the review article have noted a very dynamic increase in the number of LNG-powered vehicles. In China, the number of LNG-powered vehicles increased eightfold between 2012 and 2018, from 50,000 to almost 400,000. In Europe, nearly 5000 LNG vehicles were registered at the end of 2018. Various forecasts estimate that by 2025, the increase could be a factor of 10 to even 100.
Dual-fuel engine supply systems are commonly used in the automotive segment. Depending on the system design, the proportion of LNG in the fuel ranges from 50% to 90%. An advantage of single-fuel versus dual-fuel systems is the reduction of harmful GHG emissions. For instance, it has been estimated that about 23% of CO2 emissions could be saved by using LNG or natural gas instead of diesel.  However, due to the very limited number of LNG stations (only 280 in Europe), the servicing of these vehicles requires careful route planning.
According to the European Environment Agency (EEA), greenhouse gas emissions from transportation in the EU increased in 2018 and 2019 and did not follow the general downward trend of EU emissions. Actually, road transport accounts for the highest share of total transport sector emissions.  The contribution of the road transport sector to total emissions in the EU is distributed as follows: 17.97% of CO2, 28,12% of nitrogen oxides, 0.11% of sulphur oxides emissions.  Further action is thus required to reduce GHG emissions, particularly in road transport.
The challenges of LNG as a fuel.
Safety is one of the main challenges associated with the operation of LNG-powered vehicles. In the event of an accident, the risk of fire and tank leakages is a major concern. Otherwise, most of the technical issues have been solved for mobile applications. Nevertheless, the LNG mobile system thermodynamic and economic optimization remains a challenge and novel concepts have been proposed and experimentally tested.
For more details on recent developments in LNG systems, the full article is available on FRIDOC.
For a broader overview of the LNG industry, please save the date of the 20th International Conference and Exhibition on Liquefied Natural Gas, St Petersburg, which has been rescheduled to 3 – 7 July 2023 and will be rebranded as LNG2023. The event will be co-organized by the International Gas Union (IGU), the Gas Technology Institute (GTI) and the International Institute of Refrigeration (IIR). Please visit www.lng2023.com.
 Banaszkiewicz, T.; Chorowski, M.; Gizicki, W.; Jedrusyna, A.; Kielar, J.; Malecha, Z.; Piotrowska, A.; Polinski, J.; Rogala, Z.; Sierpowski, K.; Skrzypacz, J.; Stanclik, M.; Tomczuk, K.; Dowżenko, P. Liquefied Natural Gas in Mobile Applications—Opportunities and Challenges. Energies 2020, 13, 5673. https://doi.org/10.3390/en13215673
 Use of LNG as a marine fuel to comply with IMO 2020. Symposium on IMO 2020 and Alternative Fuels 17-18 October 2019. https://www.imo.org/en/About/Events/Pages/Symposium-on-IMO-2020-and-Alternative-Fuels--.aspx