The maritime industry's quest for decarbonization has led to increased focus on liquefied natural gas (LNG) as a transitional fuel. SEA-LNG, an industry coalition advocating for LNG adoption, emphasizes its role in reducing emissions. However, the path to net-zero shipping isn't as straightforward as switching fuels; it involves methane slip concerns, infrastructure challenges, and the urgent need for even cleaner alternatives.
LNG significantly reduces emissions of SOx, NOx, particulate matter, and CO2 when compared to conventional marine fuels. Furthermore, its low sulphur content makes it an attractive option for vessels like ultra-large containerships and capesize bulk carriers seeking to minimize their environmental impact. Supporters argue that while other alternatives are still in development, LNG can be used now as a transitional fuel, allowing companies to take immediate action in their transition to full decarbonization.
Despite these benefits, LNG's use as a marine fuel has drawn controversy due to methane slip, which is the discharge of unburned methane from engines. This issue is exacerbated by the production and transportation processes, resulting in "fugitive emissions" that contribute significantly to global warming. Recent studies have found methane slip in the plumes of ships with LPDF 4-stroke engines to be 6.4% on average, significantly higher than the 3.1% assumed by EU regulations and the 3.5% assumed by the IMO.
According to Peter Keller, Chairman of SEA-LNG, "While LNG is still in its adolescent phase, with all the growing pains, challenges, and victories, it is maturing quickly. This is a pathway we can begin to adopt now, whereas other alternatives are in their infancy". Keller also pointed out that newer LNG carriers are fitted with high-pressure engines, allowing for less methane slip and lower emission intensity levels, which are crucial for meeting maritime decarbonization targets.
However, the lack of bunkering infrastructure for LNG remains a significant challenge. The hefty investments required to establish a comprehensive LNG fuel supply chain raise questions about the long-term viability of investing in this transitional fuel when zero-carbon fuels like green hydrogen and green ammonia are being developed.
The maritime industry faces substantial obstacles in its decarbonization efforts, including a shortage of sustainable fuels and the costly transition to greener vessels. With around 90% of commercial vessels still powered by bunker fuel, and even newer ships largely reliant on traditional fuels, the urgency for the sector to decarbonize cannot be overstated.
Sources:
- https://rightship.com/insights/challenges-with-maritime-future-fuels-lng-celebration-or-controversy
- https://shipandbunker.com/news/world/732814-sea-lng-disputes-methodology-of-lng-bunker-methane-emissions-study
- https://www.eco-business.com/news/methane-slip-from-lng-ships-jeopardising-net-zero-goals-in-maritime-sector
- https://bunkermarket.com/lngs-role-in-maritime-decarbonisation-sea-lng-urges-more-investment
- https://sustainabilitymag.com/supply-chain-sustainability/moodys-shipping-decarbonisation
LNG's Path Toward Greener Shipping
The maritime industry is grappling with the environmental implications of Liquefied Natural Gas (LNG) as a fuel source. Although LNG is often promoted as a cleaner alternative to traditional marine fuels, recent studies suggest that its lifecycle emissions may not be as environmentally friendly as initially thought. For instance, a typical 175,000 cubic meters (cbm) capacity LNG carrier enables approximately 12,329,499 tCO2e/year of emissions throughout the LNG lifecycle. The industry saw record LNG vessel orders in 2021, with a net increase of 240 ships demonstrating significant market momentum despite environmental concerns.
Furthermore, methane leakage throughout the LNG lifecycle is a critical issue. Methane, the primary component of LNG, is a potent greenhouse gas that traps 86 times more heat in the atmosphere than CO2 over a 20-year time period. As such, even small leaks can negate any potential climate benefits of LNG over other fossil fuels. For example, leaks as small as 2.5% of total gas volume can offset LNG's CO2 advantages over coal in electricity generation over a 20-year timeframe.
This raises important questions about LNG's effectiveness as a bridge fuel in the transition to cleaner energy sources. While it's true that LNG combustion produces lower levels of sulphur oxides (SOx), nitrogen oxides (NOx), particulate matter, and carbon dioxide (CO2) compared to heavy fuel oil (HFO), the overall climate impact of LNG is more complex.
According to a study by Transport & Environment, using LNG as a marine fuel can lead to higher greenhouse gas emissions when considering the full lifecycle, including upstream emissions from leakage during extraction, processing, and transport, and downstream emissions from combustion and unburned methane.
Given these findings, it's crucial to reassess the role of LNG in the maritime industry's transition to greener operations. As noted by Transport & Environment, "LNG is a terrible choice for the future—using it brings new and often worse climate problems," highlighting the need for alternative, low-emission fuel sources and cargoes.
Similarly, the International Council on Clean Transportation (ICCT) warns that "continued investment in LNG infrastructure on ships and on shore risks making it harder to transition to zero-emission vessels in the future".