Revising CII to address port inefficiencies and operational constraints

Port operations play a pivotal role in determining a ship’s Carbon Intensity Indicator (CII) rating, a metric that assesses energy efficiency under IMO’s strategy to reduce greenhouse gas (GHG) emissions. In preparation for the Marine Environment Protection Committee (MEPC 82) meeting starting in late September 2024, several countries and shipping associations have submitted proposals recommending revisions to the CII framework to address challenges arising from port-related inefficiencies and operational constraints.

A key issue with the current CII system is its failure to account for emissions generated during idle periods, such as when ships are waiting at port or at anchor. Sectors like chemical carriers and short-sea trades, which can spend extended periods in port working cargo, are disproportionately impacted. Ships in the bunkering sector also experience long idle times at port or at sea, inflating their CII scores and misrepresenting their true operational efficiency. A report by Liberia and the International Chamber of Shipping (MEPC 82/INF.46) highlights that "emissions generated during idle periods, such as at port or anchor, significantly distort CII ratings, penalizing vessels for situations outside their operational control."

This issue is particularly evident in short-sea shipping (SSS) routes, such as those in the Caribbean, where frequent port calls and limited infrastructure lead to high idle times. A University of Trinidad and Tobago study (MEPC 82/INF.48) stresses that "short sea shipping in the Caribbean faces unique challenges due to the high percentage of time spent in port, where emissions occur without corresponding transport work." These inefficiencies compound the negative impact on CII ratings for vessels operating on these routes.

Port congestion further exacerbates these problems. Many ports, particularly in high-traffic regions, lack the infrastructure to accommodate the volume of ships they receive, resulting in delays in berthing and extended waiting times, which increases emissions and inflates CII scores. A report by the Republic of Korea and Pacific Environment (MEPC 82/INF.26) highlights that "port inefficiencies, including delays in berthing, contribute to higher emissions and lower CII ratings for vessels." Addressing these inefficiencies is crucial as the industry works toward decarbonisation goals.

“Many ports, particularly in high-traffic regions, lack the infrastructure to accommodate the volume of ships they receive”

One proposed solution is the implementation of Just-In-Time (JIT) arrival systems, which allow ships to adjust their speed based on real-time berthing information, ensuring they arrive at port when a berth is available, thereby avoiding idling at anchor. The Korea report (MEPC 82/INF.26) states: "JIT arrival systems have the potential to reduce fuel consumption and emissions by up to 13.5% by minimizing the time ships spend idling at anchor." However, the success of JIT systems depends on close co-ordination between ports and shipping companies, as noted by Liberia and ICS (MEPC 82/INF.46), which stress that "successful implementation of JIT arrival systems relies on the ability of ports to provide timely berthing information, and the willingness of shipping companies to adjust operations accordingly."

The Sail Fast, Then Wait (SFTW) practice further complicates this issue. In this operational model, ships sail at full speed to reach their destination, only to wait at anchor for berth availability. This results in unnecessary fuel consumption and emissions. The Blue Visby Solution (BVS) has been proposed to address this problem. According to BIMCO (MEPC 82/INF.32): "The Blue Visby Solution helps ships avoid unnecessary time spent at anchor by adjusting sailing speeds to match berth availability, reducing fuel consumption and emissions." By using real-time data and advanced algorithms, BVS optimises ship speeds and co-ordinates staggered arrivals at ports, reducing the inefficiencies caused by SFTW.