Bulkers are getting slower while travelling for longer and further to meet carbon rules, research suggests.
Emissions from bulkers have fallen by 2.5%, or 5m tonnes, since the beginning of 2021, according to US shipping market and vessel management software provider Veson Nautical.
It said the speed reduction was to comply with efficiency regulations imposed by the International Maritime Organization.
Oliver Kirkham, valuations analyst at Veson Nautical, who took a look at historical data on vessel efficiency from VesselsValue, said: “The cubic relationship between speed and required power means that higher speeds result in proportionally higher fuel consumption.”
Panamax bulkers have reduced their average speed by 3.3%, from 11.66 nautical miles per hour in 2018 to 11.27 nautical miles per hour in 2024, despite charter rates for the same vessels increasing by 23%.
“The consistent decrease in average speed across the fleet from 2021 is therefore a key contributory factor in the decrease in total CO2 emissions,” Kirkham said.
Similar trends were observed in the capesize and supramax sectors. He suggested that a reduction of sailing speed has been significant in the overall increase in operational efficiency observed in the bulk carrier fleet.
New rules aimed at lowering the carbon intensity of large bulk vessels were pinpointed as the main drivers in the reduction in sailing speed.
The IMO made it mandatory from 1 January 2023 for all existing ships to calculate their attained Energy Efficiency Existing Ship Index (EEXI) to measure their technical energy efficiency and initiated the reporting and assignment of Carbon Intensity Indicator (CII) ratings.
CII provided the first standardised operational efficiency metric in shipping, rating vessels based on fuel oil consumption, speed and distance figures collected over the year.
Shipowners were therefore required to modify non-compliant vessels to meet the newer and more stringent efficiency design criteria stipulated in the EEXI regulations.
“For older vessels, the most effective and economic way forward has been to install engine power limitation … tools which have resulted in slower average speeds and compliance with the new regulations,” said Kirkham.
More pressure is then put on shipowners to clean up their fleets, resulting in a two-tier charter market in which premium rates are paid for newer and less carbon-intensive vessels.
According to Kirkham, 99% of active bulkers are operating on single-fuel engines, based on the analysis of their specifications database.
“This is a ‘baseline scenario’ for which our verified model provides estimated fuel consumption figures, meaning the effect of dual-fuel engines on fleet-wide CO2 emissions is assumed to be minimal at present in the bulk carrier sector,” he said.
