Scrubbers were embraced in a big way in 2019/2020 in an attempt to keep the expense of the U.N.'s International Maritime Organization mandate to lower sulfur emissions from shipping. We had a few dozen posts on the issues.
The cost of simply switching to ultra-low-sulfur diesel fuel was initially modeled to add $160 to the cost of shipping a 20 foot container. Multiply by a 10-or-15,000 TEU vessel and you are starting to talk real money. So, many companies decided to keep using the higher sulfur fuel and scrub out the sulfur.
As grandmother used to say: "If it's not one tham ding it's another."
From Hakai Magazine, November 27:
The adoption of ship scrubbers—technology meant to clean up dirty fuel—has caused a surge in heavy metal pollution.
In early 2020, people in port cities around the world started breathing a little easier thanks to new regulations from the International Maritime Organization (IMO)—the overseer of international shipping—that restricted how much sulfur oxide pollution ships could have in their exhaust. Sulfur oxides, also known as SOX gases, can trigger a rash of ill effects, including heart and lung diseases and asthma. Worldwide, sulfur pollution is linked to some 400,000 premature deaths and 14 million new childhood asthma cases each year.
Shipping companies largely complied with the IMO’s new rule. But one of the prime tools in this cleanup effort—devices known as ship scrubbers—had an unfortunate side effect. While the technology has successfully diverted boatloads of pollutants from the air, it has also sent a steady flow of heavy metals into the sea, contaminating marine life and causing millions of dollars worth of damage.
The problem wasn’t negligence or oversight, according to Erik Nøklebye, the CEO of the Swedish shipping company Wallenius Lines, but rather an example of an “imperfect innovation solution.” When the IMO issued its new regulations, says Nøklebye, shipping companies essentially had two options: switch from the default heavy fuel oil to more expensive low-sulfur fuel, or install a ship scrubber—a device that sprays ocean water onto exhaust gases before they leave the engine, capturing the harmful SOX gases as a sulfuric acid solution.
Ship scrubbers come in two types: closed-loop and open-loop. Closed-loop scrubbers store the resulting sludgy, sulfurous mix in a tank that must be emptied at port. Open-loop scrubbers dump that slurry straight into the sea. Ocean water already contains a lot of sulfurous compounds, so many people weren’t too concerned about adding more. And because open-loop scrubbers save space and weight compared with their closed-loop counterparts, many ship owners have favored them.
Much more insidious compounds lurk within fossil fuel ship exhaust, however, including potent toxicants such as heavy metals and polycyclic aromatic hydrocarbons. And for ships running open-loop scrubbers—or even closed-loop scrubbers that have overtopped their storage tanks—all of this, too, has been going straight into the water. So, over time, ship scrubbers have sent a flow of toxic compounds into coastal waterways worldwide....
....MUCH MORE
