May 11, 2022

The use of LNG as a marine fuel for ships is increasing

We are in the 2020s and shipping companies are beginning to scramble, like it or not, to reduce greenhouse gas emissions. For those operating under the rules of the International Maritime Organization, the established guidelines for decarbonization aim for a reduction of 40% by 2030 and 70% by 2050, compared to 2008 emissions. others, customer demand is driving decarbonization. And for some, it’s just the right thing to do.

One way to reduce carbon emissions is to simply burn less fuel by increasing efficiency and reducing speed, but these strategies are limited and sometimes impractical. Another method is to run on alternative fuels, such as LNG, hydrogen, methanol, ammonia or electricity. Of these, LNG has been widely adopted so far.

Natural gas, of course, is itself a fossil fuel, but it burns cleaner than fuel oils such as diesel. Burning LNG creates emissions with nearly no particulates or sulfur oxides, and nitrogen oxides are significantly reduced. As such, liquefied natural gas as a marine fuel complies with SOx and NOx emission limits in Coastal Emission Control Areas (ECA). It is also seen as a bridge to low or zero carbon maritime operations.

Burning LNG as a marine fuel emits less CO2 than traditional fuel oils – around 21% to 28% less – depending on how it is measured and whether it is calibrated from well to wake, which includes all production and distribution broadcasts, or tank- wake.

LNG is also an interesting alternative fuel because it is generally cheaper than diesel. And because it burns cleaner, engines can last longer and require less maintenance.

Internationally, LNG marine fuel is rapidly being adopted by the shipping and cruise industries, which appreciate its soot-free exhaust. According to SEA-LNG, an international multi-sector industry coalition created to accelerate the adoption of LNG as a marine fuel, “2021 marked an exponential growth in orders for LNG-powered deep-sea vessels, with more than a dozen operators announcing multi- ships”. These include container ships, tankers, cruise ships, bulk carriers, car carriers and ferries. “The rapidly growing order book for LNG-powered vessels demonstrates that a growing number of shipowners and operators understand that the path for LNG is clear and well-defined,” according to SEA-LNG. The path leads to decarbonization.

General Dynamics NASSCO delivered the world’s first liquefied natural gas (LNG) powered container ship, Isla Bella, to TOTE Maritime in 2015. Her sister ship, Perla Del Caribe, was delivered to TOTE in January 2016. Photo by General Dynamics NASSCO.


Here in North America, both Maritime TOTE and maritime crowley switched to LNG as fuel for their Jones Act compliant container/ro-ro operations. TOTE has now built two 764-foot LNG-fueled Marlin-class container ships for its operations from Florida to Puerto Rico, and is currently converting its 839-foot Orca-class vessels to LNG for its operations from Puget Sound to Alaska. . And in recent years, Crowley has added two new 720-foot LNG-powered Commitment-class con-ro vessels that operate between Florida and Puerto Rico. All of these vessels operate in ECAs and comply with these standards using LNG marine fuel.

TOTE’s and Crowley’s vessels all run on dual-fuel engines, meaning they can burn fuel oil or LNG. In fact, they burn both. For LNG to ignite, either a pilot fuel explosion in the engine cylinder or a spark-triggered explosion is required. In practice, operators inject as little diesel as possible into the engine.

Cole Cosgrove, Vice President of Marine Operations at Crowley, said the percentage of diesel as pilot fuel is less than 3% in their ships. But, by choosing dual-fuel engines, operators have the flexibility to burn all diesel if LNG is not available or the price is not right.

The availability of LNG is one of the key issues in the decision to supply ships with gas.

“The important thing about introducing a new fuel is that it’s a chicken and an egg,” said John Waterhouse, CEO and Founder of Elliott Bay Design Group in Seattle. “You’re not going to build a ship to burn LNG unless you’re sure you can buy LNG fuel wherever your ship needs to go.”

Natural gas is abundant in the United States, but loading this gas into a ship requires liquefaction to make LNG. This process requires supercooling the gas to -260 (-160 C) and keeping it at that temperature. Once supercooled to liquid form, LNG can be transferred from onshore facilities to ships or vice versa. But it must be kept cold all the time or it will start to boil, increasing the pressure inside the tank it is in. If this tank is on a ship, the boiled gas can be piped to the engines as fuel. Preventing or reducing evaporations requires heavily insulated tanks, which is another stumbling block for LNG as a marine fuel, especially for small vessels.

“The problem with liquefied natural gas as a fuel is twofold,” Waterhouse said. “First, it takes up more room in the boat for an equivalent amount of energy, and second, it involves expensive cryogenic tanks to store it in. So not only does it take up more volume, but it requires very expensive special technology. .”

Tucker Gillam, Crowley’s vice president of marine assets, said storing LNG on board is definitely a challenge. “With traditional liquid fuels, you can fit the fuel tanks into the hull voids and shape quite easily,” he said, “but due to the isolation and cryogenic requirements of LNG, you usually have to have some kind of separate tank. it takes up a lot of space.”

Depending on the ship, this space could be used for cargo. LNG tanks must also be placed carefully, and not under crew quarters, to meet Coast Guard requirements.

Harvey Gulf’s five 310ft offshore supply vessels with dual-fuel engines are all being adapted to run at least partially on batteries, making them tri-fuel vessels. Harvey Gulf International Marine Photo.


One of the most visible and successful adapters of LNG as a marine fuel in the United States is Harvey Gulf International Navy, New Orleans. Led by its CEO Shane Guidry, called a “true visionary” by a Gulf engine supplier, HGIM has built and operates the first and only LNG-powered workboats in the United States, other than con-ro . HGIM’s five 310-foot offshore supply vessels with dual-fuel engines are also being adapted to run at least partially on batteries, making them tri-fuel and even more environmentally friendly vessels.

To support its own LNG-powered vessels, HGIM built an LNG storage and bunkering facility in Port Fourchon, Louisiana. Q-LNG transportationt.

The company now owns and operates the world’s first ATB LNG bunker barge, the Q-GNL 4000, which can transport 4,000 cubic meters of LNG. The 324′ barge is pushed by a 128′ tug, the Q-Ocean Serviceboth built at VT Halter Navy, Pascagoula, Mississippi. The LNG ATB provides ship-to-ship transfers and ship-to-shore transfers to small-scale marine distribution infrastructure. The ATB was built in partnership with Shell trade. Q-LNG has also planned the construction of an 8,000 cubic meter ATB to meet growing demand.

Sustained LNG demand for international shipping and entertainment cruises has also inspired polaris new energya subsidiary of Northstar Terminalsto have a 5,500 cubic meter LNG bunker barge built at Fincantieri Bay ShipbuildingSturgeon Bay, Wis. The 340’x66’x32’10” mountain bike Clean Canaveral was delivered in December. It will be pushed by the 4,000 horsepower tug Polaris under construction for McAllister LNG Towing Services at Master boat buildersBayou La Batre, Ala. McAllister will operate the ATB Polaris/Clean Canaveral for Polaris New Energy.

At the time of delivery, the buyer and the builder announced a contract for the construction of a second 5,500 m3 LNG ATB. The ATB will be a sister ship to the Clean Canaveral.

The barge, which will have a capacity of 12,000 m3 (3.17 million gallons) of LNG, will be the largest Jones Act compliant vessel of its type, and the second Jones Act compliant bunker barge that Shell has. under time charter in the United States Crowley Engineering S

In January, Bay Shipbuilding announced that it had begun construction of the largest LNG bunker barge ever built in the United States. The new LNG bunker barge for Crowley Maritime is to be chartered by Shell NA LNG. The 416ft barge will have a capacity of 12,000m3, making it the largest Jones Law compliant vessel of its type. She will be deployed on the East Coast from 2024. She will be the second Jones Act compliant bunker barge that Shell has under time charter in the United States. The ship is designed by Crowley Engineering Services.

In British Columbia, Canada, British Columbia Ferries was to receive its fourth Salish-class, dual-fuel, LNG-powered ferry in February. The 350′ car ferries were built at Remontowa Shipbuilding SA in Gdańsk, Poland. BC Ferries also converted its largest vessels, the two 550ft Spirit-class ferries, to LNG operations in 2018 and 2019 at the same shipyard. LNG-powered ships are part of BC Ferries’ Clean Futures Plan which outlines a pathway “to replace diesel fuels with cleaner, lower-carbon options.” These options also include six new Island-class diesel-electric hybrid ferries.

Also in British Columbia, Seaspan Ferries, Vancouver, has transitioned to LNG fuel with the addition of two LNG/Hybrid-Electric Ro-Ro cargo ferries serving Vancouver Island. The 488′ vessels were built by Damen Shipyards In Romania. Seaspan Ferries chairman Frank Butzelaar said the LNG hybrid vessels have operated with “more than 50% emissions reductions compared to traditional vessels”, in their first two years of service.

“We see LNG as the short-term route to reducing our carbon footprint in shipping,” Crowley’s Gillam said. “Renewable LNG has the ability to go even further, so it’s something we’re exploring and keeping an eye on. But LNG is what’s available today, and we can’t just wait for the silver bullet. Who knows what will prevail in 20 years – will it be LNG, methanol, ammonia, hydrogen? Hard to say.

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