Biofouling from microorganisms and barnacles can add as much as 55% to a ship's GHG emissions via reduced fuel efficiency, according to new research sponsored by the IMO.
Preliminary findings of the Impact of Ships' Biofouling on Greenhouse Gas Emissions report presented at COP 26 this week show the shipping industry has underestimated the effect, the IMO said in an emailed statement on Thursday.
A 0.5 mm layer of biofilm covering 50% of the hull of a 175 m bulk carrier can deliver a 25% increase in emissions, a 2.5 mm layer of barnacles with 10% coverage on a 230 m container ship can bring a 34% increase and a 5 mm layer of barnacles with 1% coverage on a 320 m tanker can cause a 55% increase, according to the report.
The full report is due to be published in February 2022.
"To reduce the GHG emissions from the maritime industry the International Maritime Organization has adopted a series of legally-binding ship design and operational performance indices that must be achieved by individual vessels," the UN body said in the statement.
"The aim is to ensure that ship operators consider options to improve the efficiency of their vessels throughout their lifecycle.
"The report clearly shows the importance of good biofouling management. It illustrates how the perceived impact of biofouling is likely to have been historically underestimated by the shipping community."