Report finds shift to LNG could worsen shipping’s climate impact


Switching to liquefied natural gas (LNG) is being widely touted as a responsible way for ships to reduce their climate impact, but it’s actually making greenhouse gas emissions far worse, according to an international environmental advocacy group.

Kendra Ulrich, shipping campaigns director for, said her group commissioned the International Council on Clean Transportation (ICCT) to study LNG’s impact, and the findings about the fuel’s shortcomings “surprised even us.”

When used instead of fuel oil, LNG significantly lowers emissions of sulfur oxides and particulate matter, but unburned fuel from incomplete combustion escapes into the atmosphere. This phenomenon, known as methane slip, is an enormous problem, Ulrich said, because methane is a highly potent greenhouse gas — it traps 86 times more heat than carbon dioxide (CO2) does. 

The report’s findings were questioned by Steve Esau, general manager of SEALNG, an industry coalition that is promoting LNG as a marine fuel. He called LNG “the most commercially viable alternative fuel to reduce shipping’s carbon footprint. It’s not the complete answer, but it’s a big improvement.”

Esau said the coalition had commissioned its own comprehensive, peer-reviewed study of LNG that examined engines from a range of manufacturers. SEALNG faulted the ICCT study for relying mainly on results from older engines that have greater methane emissions. The coalition also questioned ICCT’s methodologies, saying the council focused on the 20-year global warming potential (GWP) of methane instead of using the industry’s “universally accepted” standard of 100 years.

Ulrich called that criticism “a bit perplexing, given that the ICCT report includes both the 20-year GWP and the 100-year GWP in its analysis. For a short-lived but very potent climate forcer like methane, the 20-year GWP is more appropriate to assess the full implications of methane releases.” Stretching out methane’s warming impact over 100 years makes it seem far more benign than it is, she explained.

The Intergovernmental Panel on Climate Change has called for methane emissions to be reduced at least 35 percent from 2010 levels by 2050. Achieving that will require “rapid and far-reaching” transitions in energy, industry, buildings, transport and cities, according to the group.

“It is clear that LNG is not the climate solution that the (maritime) industry wishes it to be,” Ulrich said. “And the 20-year GWP absolutely should be considered when making policy decisions and investments in technology and infrastructure.”

She also said that of the 756 LNG ships currently in use or on order, the most popular LNG engine by far — on at least 300 of the vessels — was the worst offender for methane slip. And only 90 of the 756 use the most efficient engine type.

Ulrich said it’s important to note that these vessels stay in operation for decades, and thus “we are advocating for an immediate switch to low-sulfur distillate fuels, with diesel particulate filters to reduce particulate matter, including black carbon. Ships could switch to distillates today, without any new infrastructure or massive engine retrofits required.” also is pushing for investments to develop and implement “truly zero-emissions technologies,” such as hydrogen fuel cells, battery power storage and wind-assisted propulsion.

Asked about the ICCT report, International Maritime Organization spokeswoman Natasha Brown said the IMO secretariat doesn’t comment on reports from other organizations unless an IMO committee is asked to do so. She said that might have occurred at the March meeting of the Intersessional Working Group on Reduction of GHG Emissions from Ships, or at the 75th Marine Environment Protection Committee session scheduled for late March and April. Both of those events were postponed, however, because of the global coronavirus outbreak.

“What we can say is that, yes, the problem of methane slip from LNG is recognized and IMO has this on its agenda,” Brown said. 

By Professional Mariner Staff