LNG is being used as a transitional fuel, but other options are gaining traction. As the shipping industry steps up greenhouse gas emission targets, a decision looms.
Fuel was put in the spotlight once more when the International Maritime Organisation (IMO) announced a revised strategy to reduce greenhouse gas emissions (GHG) created by shipping in July 2023. One aspect of this was the affirmation of the body’s commitment to increase the usage of alternative zero and near-zero GHG fuels by the end of the decade.
Liquefied natural gas (LNG) has been seen as a transitional fuel for shipowners worldwide. That is unlikely to change, although it is far from a perfect solution. That’s because carbon dioxide emissions are only 20-25 percent lower when compared to using marine diesel.
“LNG is used as a transitional fuel, but it is imperfect. The benefit of LNG over other fuels is that it is a widespread commodity that is easily available. It will be in demand and can be a transitional fuel for years to come even if other options with lower or even no GHG emissions are available,” Mr Johan P. Tutturen, Senior Technical Advisor, Green Transition Group, at Clarksons, reports. “The issue with LNG is that it contains carbon. While the emissions are less than traditional maritime fuel, that may still be an issue. There is a reason we are seeing such a heavy focus on other fuels.”
Those other fuels include ammonia and methanol. The former could have the largest impact as it may allow zero-carbon shipping operations. Before that happens, the risks of using ammonia must be fully addressed.
“The maritime industry is looking into ammonia, and this could potentially be something big since it doesn’t contain any carbon,” Mr Tutturen points out. “On the downside, it is toxic and corrosive on materials like copper, copper alloys and zinc, creating a set of challenges. While safety measures have been built in, more stringent and universal regulations will be needed.”
Methanol is growing in popularity as an alternative to marine diesel since it is less toxic than ammonia and contains less carbon than LNG which places it in the middle. According to DNV’s Alternative Fuel Insights database, there were 48 orders for methanol-fuelled ships compared to only 14 for LNG-fuelled vessels in July 2023.
“There are two challenges for those wanting to use methanol or ammonia as shipping fuel. The first is that they require larger tanks because the calorific is far less than marine diesel and LNG. Shipowners are forced to find ways to accommodate these with the most probable solution being less cargo space,” Mr Tutturen explains. “The second issue is that the technology and value chains for both are being developed.”
While dual-fuel ships capable of using methanol can be found on the open seas, ammonia engines are still in the development stage. Notable efforts include DNV’s partnership with MAN Energy Solutions, Eltronic Fueltech and Technical University of Denmark on the AEngine project. Work on the first two-stroke ammonia-powered engine is close to the testing stages with a commercial-ready engine expected to be produced in 2024.
LNG will remain a transitional fuel in the coming decades. However, Mr Tutturen expects ammonia and methanol to grow simultaneously. Each one has its own pros and cons that shipowners should consider before making a decision. The value chains for each one also need to be built up and that is going to take time–something ship owners may not have.
“Predictability is paramount for ship owners. They are not in this business for fun and they hate surprises. Their decision will boil down to the cost, availability and stability. The industry knows fuel options are coming but many are waiting to see how this plays out before making a decision,” Mr Tutturen says.
LNG, ammonia and methanol will play a role in the shipping industry’s push to reduce GHG by 70 percent between now and 2040. The choice itself is not as important as the action to move away from marine diesel.
“The planet is more mature and there is greater awareness surrounding the damage CO2 emissions cause. We can’t use fossil fuels for an infinite amount of time, and we can’t continue to release the same amount of carbon emissions. Going on as is isn’t an option,” Mr Tutturen concludes.
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