The World Shipping Council wants the maritime industry to use a ‘well-to-wake’ measure for ships’ emissions, rather than a simple CO2 measure at the stack. It’s a good point.
Ocean shipping firms will do only as much as is required. And the current picture based on the International Maritime Organization (IMO)’s CII regulations, doesn’t require taking account of emission sources in the supply chain of fuels, or the greenhouse effect of process emissions such as methane leaks.
IMO’s own study shows that LNG may reduce smokestack emissions, but total greenhouse emissions are even greater than conventional fuel oil.
A study by scientists from Queen Mary University oof London scientists measured methane and CO2 emissions from marine power sources. They instrumented a new LNG carrier (2021 completion), on both the main engines and the generator engines.
Note that generator engine emissions are not considered in monitoring the emissions from a ship, according to current standards.
The methane slip, escape of methane through gaps and orifices in the machinery, was found to be quite low, and the generator engines were found to be the biggest source.
This is a quite new ship and one might expect lower emissions from the latest technology. But the study points to the need for including generator engines in the rules and in the monitoring. Studies on other ships and other voyages would be a good idea, and to their credit, the ship owner, Cheniere, has said it will continue to study emissions from its fleet.