Green lobby says exhaust gas cleaning system wash water is in contravention of UNCLOS part XII, so technology should be banned
Despite thousands of vessels now having exhaust gas cleaning systems installed to comply with a global sulphur cap, green lobby groups have renewed their push to have the technology banned.
The systems, known also as scrubbers, remove the sulphur oxide emissions from the exhaust of engines powered by marine fuel oil which has a higher sulphur content than permitted.
However, the green groups, led by Friends of the Earth International and Greenpeace, have put a paper into the marine environment committee of the IMO saying that the wash water from scrubbers contravenes parts of UNCLOS, the UN law of the sea convention.
The marine pollution contention Marpol, sets a 0.5% sulphur in fuel limit for vessels in global trade, and 0.1% for vessels sailing in the growing number of emission control areas.
Scrubbers were approved by the IMO as an equivalent way to comply with the regulations by allowing owners to use much cheaper fuel oils.
The significant price difference, or spread, between low sulphur distillate fuels or diesel fuels compared to cheaper fuel oils has made scrubbers extremely popular, with DNV now listing nearly 5,000 vessels with the technology installed.
The green lobby group have been arguing however that when scrubbers are operated in an open loop cycle the wash water used t clean the exhaust is too polluted to be discharged into the sea.
This they say is a contravention of UNCLOS which states that signatories should not be solving one environmental issue by creating another, and that the wash water discharge is harmful to the environment.
Both sides of the argument have produced their own paid for research to make claims about wash water impact on the water environment which will now bog the discussion into scientific and legal interpretations that the Imo is now being asked to address.
During the meeting of the marine environment protection committee in December 2022 member state delegations either spoke in favour or against the discussion being looked at by a legal department and for the technical aspects to be discussed at MEPC’s sub-committee on Pollution Prevention and Response.
