The Role of LNG in Decarbonizing Maritime Shipping

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With increasing emissions regulations, many shipowners are turning to alternative fuels like liquified natural gas (LNG) to power their vessels. LNG is proving popular due to its cost-effectiveness and reduced greenhouse gas emissions, reports Wärtsilä .

All about LNG

LNG is natural gas cooled to -162°C (-260°F) into a clear, odorless liquid, primarily composed of 85–95% methane. It is an efficient form of energy ideal for ship propulsion due to its compactness and ease of storage and transport. LNG is used for electricity generation, heating, cooking, and transportation. In the shipping industry, it powers ship propulsion, auxiliary power generation, and other onboard energy needs, helping meet stricter emissions regulations.

LNG is produced from natural gas extracted from underground reserves. BioLNG is derived from biogas generated from organic waste like food scraps and manure. BioLNG, being renewable, further reduces the carbon footprint of LNG-powered ships.

Compared to diesel fuel oil, LNG offers significant emissions reductions: 20-30% less CO2, 15-25% less total GHG, 90% less NOx, 99% less SOx, and almost no particulate matter. However, LNG has a lower energy density, requiring larger fuel tanks for the same range as diesel.

LNG reduces emissions and is cost-competitive, with a growing global network of bunkering facilities. However, it requires specialized equipment and training, and there is a risk of methane slip, though modern engines minimize this issue. LNG is cleaner than traditional marine fuels but is still a fossil fuel. BioLNG offers a more sustainable alternative. LNG is seen as a transition fuel towards more sustainable options like methanol and ammonia.

LNG provides a concrete step towards decarbonization, reducing emissions and compliance risks. It opens possibilities for future use of bioLNG and synthetic methane. LNG produces about 20-30% less CO2 than heavy fuel oil. Lifecycle emissions depend on methane slip during production and transport, engine efficiency, and energy sources for liquefaction. Modern technologies minimize methane slip, making LNG a lower-emission option.

The global LNG market is projected to grow significantly, with an increase in LNG bunkering infrastructure making it more accessible for shipping. Many modern LNG tankers use LNG for propulsion and auxiliary power, benefiting from environmental advantages, efficient boil-off gas management, and fuel efficiency.

By 2024, over 2,400 vessels were equipped to operate on LNG, with another 1,000 on order, including cruise ships, tankers, containerships, and RoRo ferries. LNG offers lower emissions, cost competitiveness, and increasing global availability, making it an attractive alternative marine fuel.

LNG plays a crucial role in the shipping industry’s transition to cleaner fuels. It is seen as a stepping stone towards the adoption of future fuels like green methanol and carbon-free green ammonia, aligning with the IMO’s goal of reducing greenhouse gas emissions by at least 50% by 2050. Investing in dual-fuel engine technology allows for flexibility in using LNG now and transitioning to zero-carbon fuels in the future.

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Source: Wärtsilä