NGO Questions LNG Fuel's Climate Impact

LNG bunkering vessel (Port of Rotterdam)

Published Jun 26, 2018 4:48 PM by The Maritime Executive

European NGO Transport and Environment has released a new study of the cost-effectiveness of LNG as a marine fuel for reducing greenhouse gas emissions, and has reached the controversial conclusion that it is a $22 billion "expensive diversion" for Europe. 

The report, produced by a partnership between researchers at the University College London (UCL) Energy Institute and consultancy MATRANS Ltd., uses economic modeling to forecast the cost and emissions impact that LNG bunkering would have on GHG output. Its key finding is not favorable: the researchers determined that "there is no significant CO2-equivalent reduction achieved through the use of LNG as marine fuel relative to the reduction required to achieve the IMO’s 2050 objectives [of a 50 percent cut] . . . particularly when including upstream emissions and all sources of [greenhouse gases]."

Transport and Environment warned that the cost of switching some vessels to LNG vessels would be high; would likely result in a limited reduction in GHG emissions; and could potentially result in a net increase in CO2-equivalent terms. "In a scenario where LNG uptake is . . . incentivised, [LNG infrastructure] would cost Europe an additional $22 billion up to 2050, with at best a [6-10 percent] reduction of GHG . . . and all this under an optimistic methane leakage scenario," T&E wrote. "Should methane leakage rates be higher, a switch to LNG could actually increase GHG emissions compared to the diesel fuel it replaces."

Ton per ton, methane is a much more potent greenhouse gas than CO2 - about 80 times more over a two-decade period and 30 times more over a 100-year period. The amount of methane leakage that occurs during natural gas E&P, transport, liquefaction and combustion is much debated, and has considerable bearing on the GHG profile of LNG as a marine fuel. 

T&E acknowledged the localized public health benefits of burning LNG instead of heavy fuel oil. LNG propulsion can nearly eliminate a vessel's SOx and PM emissions, and it offers a decrease in NOx emissions of up to 90 percent compared to HFO. While these pollutants are hazardous to coastal residents, and reducing them improves local environmental quality, they do not have bearing on climate change (with the exception of the cooling effects of SOx emissions, which are virtually eliminated by LNG). 

SEA/LNG calls for more research

The SEA/LNG coalition of LNG bunkering advocates recently called for more research on the net GHG impact of LNG as a marine fuel to make a "credible, fact-based case" to the shipping industry. 

In May, the group acknowledged that there are questions regarding the GHG impact of methane emissions in natural gas production and transportation and methane slippage from marine engines (unburned methane fuel in the exhaust stream). It also highlighted studies that conclude that LNG has a significant potential to reduce total lifecycle GHG emissions. To bring its own analysis to bear on the question, SEA/LNG is commissioning a new study to compare well-to-wake GHG emissions of LNG-fueled propulsion with emissions from low sulfur fuels, high sulfur fuels with scrubbers, and future eco-friendly propulsion technologies.