The Liquefied Natural Gas (LNG) is fast gaining strength as alternative marine fuel, as a worldwide push is on to sharply reduce or eliminate harmful emissions from the burning of fossil fuels by ocean going ships.
Recent indications showed that more shipping lines are considering LNG, investing heavily in the full or partial technology that would aid its conversion.
The International Maritime Organization (IMO), a specialized agency of the United Nations and a kind of parliament composed of representatives from each country in the world, voted in April 2018 to effectively phase out sulfur emissions from shipping. The now-famous IMO 2020 resolution, which drops the allowable limit of sulfur in fuel to 0.5%, entered into force on January 1, 2020.
The IMO also voted to reduce the total amount of greenhouse gas emissions by 40% by 2030 and by 50% by 2050 when compared with 2008 levels.
It vowed to pursue efforts to eliminate greenhouse gas emissions altogether as well. Experts have identified various ways to get to the IMO 2050 goal, such as adopting the use of biofuel (biogas or biodiesel), methanol, ammonia and hydrogen, among others.
But the use of LNG appears to be gaining momentum with more firms going for the clean fuel.
The French container shipping company CMA CGM had recently launched the first in a fleet of nine LNG-powered, ultra-large container ships, each of about 23,000-TEU (twenty-foot-equivalent-unit) capacity.
The vessels are about 400 meters (1,312 feet) long and 61 meters (200 feet) wide.
Also, Mitsui O.S.K. Lines announced that it is investigating how to create large hybrid LNG/battery commercial ships.
Such vessels, according to the firm, would use energy stored in batteries while they navigate in coastal and harbor waters. But it will take time to change over from the existing fleet Antony Linden, business development director SEA, Pacific and India for class society DNV GL said there are 110,000 vessels in the world fleet. That world fleet, he added, is “mostly powered by diesel; change will take a long time.”
Mitsubishi Shipbuilding Co., Ltd., a Group company of Mitsubishi Heavy Industries, Ltd. (MHI) based in Yokohama, has also concluded a contract with Mitsui O.S.K. Lines (MOL) to build two LNG-fueled ferries.
These vessels, according to Mitsubishi, would be built at the Shimonoseki Shipyard & Machinery Works, with successive completion and handover scheduled for the end of 2022 to early 2023.
In another development, the ABS-classed Saga Dawn, the world’s first LNG Carrier to be fitted with an innovative cargo containment system based on IMO requirements for independent type A tanks, has been delivered to Saga LNG Shipping.
LNG is basically a super-cool and pressurized form of the flammable compound gas, methane, which has one atom of carbon and four atoms of hydrogen.
The global LNG trade reached 316.5 million metric tonnes in 2018, up by 9.8% year-on-year when compared with 2017, according to the International Gas Unit World LNG Report 2019.
For decades, LNG carriers have been equipped with mechanisms that allow them to burn the boil-off gas in steam turbines. Later, dual fuel diesel-electric engines were deployed that could use both the boil-off gas and marine diesel oil and/or heavy fuel oil to generate power for propulsion. However, some LNG tankers will re-liquefy the boil off gas and will return it to the cargo tanks.
Some other kinds of oceangoing craft are equipped to use LNG as a fuel, although they are represent tiny volumes compared with the LNG fleet. These include car and passenger ferries, general cargo ships, patrol vessels, ro-pax, ro-ro, and tugs.
