Tag Archives: emissions measurement

Benefits of slow steaming exaggerated?

Studies by Simpson, Spence and Young, a leading global shipbroking firm, seem to indicate that emission benefits of slow-steaming have been exaggerated.

One reason offered is that the ‘cubic law’, which says that fuel consumption rises as the cube of ship speed, is erroneous for many vessels, and is only approximately true at the designed speed of the ship.

Another problem is that slow-steaming effectively reduces capacity, requiring more ships to cover a route with a regular schedule, for instance. Those extra ships produce more emissions even though the per-ship emissions might be smaller.

Capacity is not a problem at present. There’s not enough cargo. But scheduled service may suffer.

There are a lot of moving parts in considering emissions release.

The best way to attack the problem may be to get to zero or low-emission ships as quickly as possible. But in the short run, these considerations in he study are worth thinking about.

By Charlie Bartlett, technology editor 15/05/2023

Benefits of slow-steaming on emissions exaggerated, studies find – The Loadstar

Shipping must have ‘well-to-wake’ emissions standards, says WSC

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.

By Charlie Bartlett, Technology Editor 26/08/2022

Shipping must have ‘well-to-wake’ emissions standards, says WSC – The Loadstar

Low loads double methane slip on LNG carrier voyage

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.

Gary Howard | Jun 14, 2022

Low loads double methane slip on LNG carrier voyage