How to measure, monitor and mitigate shipboard methane emissions

Mr Schubert said Avenir LNG invests in technology and people to minimise LNG and methane releases from its vessels, terminals and bunkering stations, as well as safety equipment to halt operations rapidly if emissions are identified.

This includes emergency shut downs and quick-release couplings on LNG loading and unloading systems, training crew to prevent incidents and raising awareness of potential releases.

“We keep emissions under control and have no methane releases to the air and we do drone flights for inspections,” said Mr Schubert. “We have the right training and procedures for staff to use equipment correctly, to improve efficiency and reduce emissions risk.”

Avenir LNG has dual-fuel engines running primarily LNG on its ships and has started testing for methane slip with results of this set to come from March 2023. “If we know there is methane slip, we would invest to mitigate it,” said Mr Schubert.

Queen Mary University of London is part of a multi-partner, three-year research project to study methane emissions from LNG carriers and other ship types. Its industry partners include Cheniere, Chevron, Sempra, Exxon, Williams, Pioneer, GTI, BAE Systems, Johnson Matthey, SIGTTO and SGMF.

Mr Balcombe said the joint industry project was looking for more partners to gain access to more ships to broaden the study and advise on emissions mitigation from all sectors.

This follows a study in 2021 to measure emissions and releases from 2021-built gas carrier Gaslog Galveston as it completed a round trip for charterer Cheniere from Corpus Christi, US, to Zeebrugge, Belgium.

“We looked at flaring, vent lines and engine exhaust for any leaks of methane or other gas sources,” said Mr Balcombe. Findings from this study could be expanded and extrapolate to other ships in the future.

What the university found was methane slip is highly dependent on engine load​ and more slip was identified at low loads in the generator engines​.

​“Different engines show different slip rates, so it would be good to know how this changes across other vessels,” said Mr Balcombe.

The study also found releases through venting and fugitive emissions were extremely low, other than when there was a switch between diesel and LNG fuels, which requires venting through the pipes.

Webinar poll results

Attendees were asked to vote on a series of poll questions during the webinar. Here is a summary of the results.

Is methane slip monitoring the norm now for LNG carriers?

Yes: 36%

No: 64%

Do we need a new generation of retrofit solutions to reduce methane emissions from the fleet?

Yes we do: 84%

No we do not: 16%

How safe is LNG bunkering?

Extremely safe: 22%

Safe: 61%

Neutral: 17%

Unsafe: 0%

Vessels between 5 and 10 years old are now seen as less eco-friendly due to their dual-fuel engines generating more methane slip than new tonnage. Should the owners of these relatively new vessels be provided with a ‘levelling up’ moratorium to allow them to compete with newer and more methane-efficient vessels?

Strongly agree: 7%

Agree: 39%

Neither agree nor disagree: 31%

Disagree: 16%

Strongly disagree: 7%

Should shipping become more transparent with reporting actual emissions given the public’s apparent mistrust of manufacturer-published emissions data since the Dieselgate scandal?

Strongly agree: 39%

Agree: 45%

Neither agree nor disagree: 6%

Disagree: 6%

Strongly disagree: 4%

Source: Riviera Maritime Media

On Riviera’s Measuring, monitoring and mitigating shipboard methane emissions webinar panel were (left to right) Avenir LNG commercial director for LNG bunkering Jan Schubert, Emsys Maritime managing director Simon Brown and Queen Mary University of London senior lecturer in chemical engineering and renewable energy Paul Balcombe.