Optimizing port arrivals could cut emissions by up to 25%, report says

December 6, 2024, by Fatima Bahtić

Optimizing port arrivals to take into account port congestion or waiting times could reduce voyage emissions by up to 25% for some vessel types, a new report shows.

A new study, carried out by UCL and UMAS, analyzed ship movements between 2018-2022. The research found that ships spend between 4-6% of their operational time, around 15–22 days per year, waiting at anchor outside ports before being given a berth.

In line with that, the average potential emissions saving for the voyages could be approximately 10% for containerships and dry bulkers, 16% for gas carriers and oil tankers, and almost 25% for chemical tankers, if the issue of port arrivals is resolved in a more efficient manner, the report states.

“The IMO set ambitious GHG reduction targets in 2023. Meeting those targets means unlocking all efficiency opportunities – including voyage optimisation and operations around ports. This will only happen if CII remains a holistic metric covering all emissions, and incentivising shipowners, charterers and port stakeholders to break down long-running market barriers and failures,” Tristan Smith, Professor of Energy and Transport at the UCL Energy Institute, said.

Port operations during the COVID-19 pandemic

Between 2018 and 2022, chemical tankers, gas tankers, and bulk carriers saw a significant increase in their waiting times at anchor before being able to berth at ports. According to the report, these delays, which are calculated as a percentage of their annual operating time, surged to around 5.5% to 6% by 2022.

This marked increase stands in contrast to the more stable waiting times observed for oil tankers and containerships, where delays hovered around 4.5% and 5.5%, respectively, during the same period.

The rise in waiting times for certain vessel types can be traced to several factors, including port congestion that was exacerbated during the COVID-19 pandemic and the subsequent post-pandemic surge in global maritime trade.

The pandemic significantly disrupted global supply chains, including those in the maritime industry, leading to a backlog of vessels waiting to dock.

Smaller vessels experience longer waiting times

The study also found that smaller vessels tend to experience longer waiting times, though this varies depending on the type of vessel. According to a previous report by the same authors, Transition Trends, poor operational efficiency has been identified as a key factor contributing to rising emissions in the maritime sector between 2018 and 2022.

“Our analysis highlights the current and growing issue of port waiting times and the inefficiency they represent. This is just one piece of the broader operational inefficiency puzzle that is key to generating the short-term emissions reductions that will need to be achieved before 2030. By targeting these idle periods, the IMO can unlock significant emissions reductions while also reinvigorating improvements in operational efficiency, which have stagnated since 2012,” Haydn Francis, Consultant at UMAS, stated.

The underlying causes of prolonged waiting times are rooted in common operational practices, such as the “first-come, first-served” scheduling system and the “sail-fast-then-wait” approach, as well as broader systemic issues.

Specifically, these include port congestion, a lack of standardized data exchange, inflexible charter parties (the agreements between shipowners and charterers), and limited coordination among the various stakeholders involved in loading and unloading operations, including port authorities, cargo owners, and others.

Operational practices of ports and CII regulations

The study further suggests that the International Maritime Organization’s (IMO) Carbon Intensity Indicator (CII) regulation should take into account the full range of a vessel’s operational activities, not just the “sea-going passage,” as some have proposed.

By doing so, the IMO could encourage stakeholders to collaborate more effectively to reduce the greenhouse gas (GHG) intensity of vessels across the entire value chain, rather than focusing solely on the segments where shipowners or charterers have direct control. Limiting the CII to only certain aspects of the voyage could allow well-known market barriers—particularly those at the interface between ship and port operations—to remain under-addressed, hindering progress toward achieving the IMO’s 2030 emissions reduction targets.

The study also highlights the significant role that port congestion plays in overall system inefficiencies. This issue has been particularly concerning for low-income member states, which view port congestion as a barrier to their decarbonization efforts.

While the study did not delve deeply into this issue, it suggests that addressing operational inefficiencies at the interface between ships and ports could also support the broader goal of a just and equitable transition to a low-carbon maritime industry, it was concluded.