LNG Ships Are Still Emitting Dangerous Amounts Of Methane

Some shipping operators have been exploring the potential for curbing emissions by switching to engines that run on LNG, with LNG made from renewable biogas holding out the prospect of further emissions reductions.

But the latest report from the International Council on Clean Transportation (ICCT) highlights the need to control the release of unburned methane from marine engines that have been converted to run on LNG, warning that substantial quantities of the the gas can leaked through so-called ‘methane slips’.

Methane as a dangerous greenhouse gas

The researchers comes amidst predictions demand for LNG fuel for ships trading within the European Union could triple between 2019 and 2030.

The report calculatres that switching to LNG could deliver carbon emissions savings, but these could be partially offset by increased methane emissions.

It found that using 100 per cent renewable LNG in 2030 could cut life-cycle greenhouse gas emissions 38 per cent below 2019 levels based on 100-year global warming potential.

However, the researchers also warned that the approach could also raise emissions by six per cent based on 20-year warming potentials because of methane’s strong near-term warming effects.

The ICCT described methane as a “dangerous” greenhouse gas, which is has more than 80-times more climate warming potential than carbon dioxide in the short-term.

Methane emissions could double by 2030

Researchers concluded that even when using 100 per cent renewable LNG, total methane emissions could double by 2030 compared to 2019, primarily through methane slips.

According to the Intergovernmental Panel on Climate Change, methane emissions need to fall by one-third between 2019 and 2030 in order to limit global temperature rise to 1.5C. The EU has previously acknowledged the importance of cutting its methane emissions, having committed to the Global Methane Pledge which aims to cut global methane emissions by 30 per cent between 2020 and 2030 as well as stating that it would reduce its overall greenhouse emissions by at least 55 per cent below 1990 levels by 2030 under its Fit for 55 plan.

Bio or e-LNG (renewable LNG) could cost

The report also found that bio or e-LNG (renewable LNG) could cost as much as seven times more than fossil LNG in the European Union in 2030, with the researchers arguing subsidies or other policies would likely be needed in order to encourage its use.

“Our estimates show that subsidising renewable LNG marine fuels would cost the European Union nearly €18bn per year in 2030 but methane emissions chip away at its potential life- cycle emissions benefits,” said Jane O’Malley, study co-author and ICCT fuels researcher.

“Other fuels like green methanol and renewable diesel cost just as much and don’t have the methane problem.”

Leader author and marine programme lead Dr Bryan Comer re-iterated the importance of minimising methane slips from new and existing ship engines, even when they are using renewable LNG.

“Low-methane-slip engines are the exception in today’s fleet, but they need to be the rule,” he said. “Regulations like FuelEU Maritime could be strengthened to discourage the use of high-methane-slip engines.”

The report has suggested that in order for renewable LNG to significantly contribute to achieving climate goals, methane slips from engines need to be “virtually eliminated” and methane leaks upstream need to be greatly reduced.

Additionally, methane leaks from onboard fuel tanks and cargo tanks, which the researchers said that are still working to adequately quantify, should be near zero.