Optimising port arrivals could cut emissions by 25 per cent

The average potential emissions saving for the period considered (2018-2022) was found to be approximately 10 per cent for containerships and dry bulkers, 16 per cent for gas carriers and oil tankers, and almost 25 per cent for chemical tankers.The study found that these ships spend between 4-6 per cent of their operational time, around 15-22 days per year, waiting at anchor outside ports before being given a berth.

Tristan Smith, Professor of Energy and Transport at the UCL Energy Institute, said: “The International Maritime Organization (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 carbon intensity indicator remains a holistic metric covering all emissions, and incentivising shipowners, charterers and port stakeholders to break down long-running market barriers and failures.”

Over the period 2018-2022, chemical tankers, gas tankers, and bulk carriers spent increasing waiting times at anchor before berthing, rising to 5.5-6 per cent of time per annum, by 2022.Waiting times for oil tankers and containerships stayed approximately constant (around 4.5 per cent and 5.5 per cent respectively). Some of the increase in waiting times may be attributable to the port congestion caused by COVID-19 and by a post-pandemic surge in maritime trade.The study also found that smaller vessels generally experience longer waiting times, though this varies by vessel type. A previous report by the authors, Transition Trends, has shown that poor operational efficiency is one of the main reasons for increased emissions in the period 2018 to 2022.

Dr Haydn Francis, Consultant at UMAS, said: “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.”