Technology group Wärtsilä on Wednesday (19 June) gave an expert overview on top 17 questions related to LNG bunker fuel in this insight article including if LNG is a future fuel: 

Your choice of fuel affects both your profitability and your vessel’s environmental compliance. Liquefied natural gas (LNG) is a safe and cost-effective fuel that reduces greenhouse gas emissions and other harmful pollutants. LNG is playing a key role as a transition fuel and is widely seen as the first step towards decarbonising the maritime industry.

Switching to LNG as fuel for ship propulsion requires investment but can save you fuel costs, increase your profitability and reduce compliance risks. The expert answers to these 17 questions will tell you what you need to know about LNG as an alternative fuel for shipping.

What is LNG?

LNG is natural gas that has been cooled to -162°C (-260°F), turning it into a clear, odourless liquid that is easy to ship and store. LNG is typically 85–95% methane, which contains less carbon than other forms of fossil fuels. It is a compact, efficient form of energy that is ideal for ship propulsion.

What is LNG used for?

LNG is primarily used as a clean-burning energy source. It is used for electricity generation, heating, cooking, and as a transportation fuel. LNG is also used as a raw material for products like fertilisers and plastics.

In the shipping industry, LNG as fuel is used for ship propulsion, auxiliary power generation and other onboard energy needs. LNG as an alternative fuel for shipping has gained wide popularity due to its clean-burning properties and potential to help meet stricter emissions regulations.

What are the sources of LNG as fuel for ships? What is bioLNG?

LNG as fuel for ships is produced from natural gas extracted from underground reserves, including both onshore and offshore gas fields.

BioLNG is LNG produced from biogas, which is generated from organic waste like food scraps, agricultural waste, manure and sewage sludge. BioLNG is considered a renewable fuel and can further reduce the carbon footprint of ships using LNG fuel systems.

 Is LNG just methane?

LNG is primarily methane (typically 85–95%), but it also contains small amounts of ethane, propane and other hydrocarbons. LNG can also contain trace amounts of nitrogen and carbon dioxide. The exact composition of LNG may vary depending on the source of the natural gas and the liquefaction process used.

 LNG fuel vs. fuel oil: is LNG better than diesel?

Compared to diesel fuel oil, LNG offers several advantages. LNG produces significantly lower emissions when burned, including:

• 20–30% less CO2 
• 15-25% less total GHG
• 90% less NOx 
• 99% less SOx 
• Almost no particulate matter (PM) 

LNG engines are also quieter. 

However, LNG has a lower energy density than diesel, so using LNG as an alternative fuel for shipping will require more fuel and therefore larger fuel tanks to achieve the same range.

 What are the advantages and disadvantages of LNG fuel?

The key advantages of LNG as fuel include reduced emissions and cost competitiveness. There is also an established and continuously growing global network of LNG bunkering facilities.

The disadvantages of using LNG as fuel for ships include the need for specialised equipment and training and the potential for methane slip.

Methane slip is when unburned methane, a potent greenhouse gas, escapes into the atmosphere. Modern dual-fuel engines will minimise this issue. Depending on engine type and load, you can reduce methane slip by up to 65% by upgrading your ship’s existing engines. Over the last 30 years, Wärtsilä has reduced the methane slip from its engines by around 90%.

 Is LNG environmentally friendly?

LNG is cleaner burning than traditional marine fuels, but it is still a fossil fuel. BioLNG, which is LNG produced from organic waste or biomass, can be considered a more sustainable alternative to fossil-based LNG as it has a lower carbon footprint. However, the production and combustion of bioLNG still emit some greenhouse gases. LNG can be seen as a bridging fuel in the transition to alternative fuels like methanol and ammonia, which aren’t yet widely available at scale.

 Is LNG a future fuel?

LNG both is and isn’t a future fuel. It enables lower greenhouse gas emissions and reduces other harmful air pollutants compared to fuel oil, but it is still a fossil fuel. Sustainable future fuels are crucial for maritime decarbonisation, but the current cost, limited availability and insufficient infrastructure are challenging for operators. This gives LNG an important role to play in the shipping industry’s transition to a zero-carbon future.

As more ports develop LNG bunkering infrastructure and more ships are built with LNG fuel systems, the use of LNG as an alternative fuel for shipping is expected to increase. LNG is considered a stepping stone on the path to decarbonisation as the industry moves closer to using true future fuels such as methanol and ammonia.

Note: The full article by Wärtsilä can be found here.

Photo credit: Chris Pagan on Unsplash
Published: 24 June, 2024