Closed loop marine exhaust scrubbers use cleaning agents such as caustic soda to treat the wash water from the scrubber. Delivering caustic soda to vessels is challenging at some ports because there are no dedicated caustic soda barges.
The issue will become prevalent in Singapore, Pierre-Alexis Mosnier, shipping advisory company Mareneco chief executive told the delegates of the Americas Sulphur Cap 2020 conference in Houston yesterday. Singapore is the biggest bunkering port in the world and has banned the use of open loop scrubbers in its territorial waters. Open-loop scrubbers use seawater to capture sulphur from engine exhausts before discharging this wash water back into the ocean after treatment. In January 2020, when the global marine fuel regulation comes into force and marine fuel sulphur limit is capped at 0.5pc from the current limit of 3.5pc, the use of closed loop scrubbers to meet the regulation will increase. Most of the vessels that fuel in Singapore do not call alongside the port but stay at anchorage, and the bulk of the marine fuel sold in Singapore is delivered to vessels via barges. But there are no dedicated caustic soda barges currently in Singapore, and the scrubber wash water cleaning agent can only be delivered via truck.
The use of open loop scrubbers is not banned in Florida, but there is a different logistical challenge in the ports of Miami and Fort Lauderdale. The cruise ship industry has embraced the use of scrubbers. For the vessels using closed loop scrubbers, there is limited production of caustic soda in Florida. The product has to be delivered via train or truck, which adds to its cost. Separately, some ports do not allow deliveries of caustic soda, which is a hazardous material. The vessel crews have to be trained to handle it safely.
Besides Singapore, open loop scrubbers are banned or restricted in the territorial waters of Latvia, Lithuania, Belgium, Dublin in Ireland, Fujairah and Abu Dhabi in the UAE, India, China, the US states of Connecticut, Massachusetts, California and Hawaii, and some locations around Norway. Because open loop scrubbers use seawater, their use is also not allowed in freshwater bodies such as lakes and rivers.
Mosnier noted that instead of caustic soda, users of closed loop scrubbers can use magnesium oxide, magnesium hydroxide or sodium carbonate as wash water cleaning agents. Some shipowners prefer magnesium oxide or magnesium hydroxide because caustic soda prices fluctuate more. Argus assesses and publishes prices of caustic soda in its Chlor-Alkali and Derivatives report.
