Tag Archives: sulphur emissions ships

How Air Pollution Infiltrates the Seas

A global effort to curb pollution from the heavy fuel oil burned by most big ships appears to be encouraging water pollution instead. A 2020 regulation aimed at cutting sulfur emissions from ship exhaust is prompting many owners to install scrubbing systems that capture pollutants in water and then dump some or all of the waste into the sea.

Some 4 300 scrubber-equipped ships are already releasing at least 10 gigatons of such wastewater each year, often in ports and sometimes near sensitive coral reefs…. The shipping industry says pollutants in the waste don’t exceed national and international limits, and that there’s no evidence of harm. But some researchers fear scrubber water, which includes toxic metals such as copper and carcinogenic compounds called polycyclic aromatic hydrocarbons, poses a rapidly growing threat, and they want to see such systems outlawed.

The emerging debate is the result of a 2020 regulation put into place by the International Maritime Organization (IMO), an arm of the United Nations that works with 174 member states to develop common rules for international shipping. By banning the use of sulfur-heavy fuel oil, the rule intended to reduce pollutants that contribute to acid rain and smog. IMO estimated the rule would slash sulfur emissions by 77% and prevent tens of thousands of premature deaths from air pollution in ports and coastal communities.

But cleaner fuel can cost up to 50% more than the sulfur-rich kind, and the rule allows ship owners to continue to burn the cheaper fuel if they install scrubbers. In 2015, fewer than 250 ships had scrubbers (often to comply with local regulations); last year, that number grew to more than 4300, according to industry figures.

A scrubber system sends exhaust through a meters-tall metal cylinder, where it is sprayed with seawater or freshwater, depending on the type, at rates comparable to gushing fire hydrants, to capture pollutants. In the most popular systems, called open loop scrubbers, seawater is discharged to the ocean after little or no treatment. Other systems retain sludge for disposal on land and release much smaller (but more concentrated) amounts while at sea….Researchers are particularly worried about discharges in areas that IMO has designated as ecologically sensitive. The Great Barrier Reef, for example, receives about 32 million tons of scrubber effluent per year because it’s near a major shipping route for coal. Ships also release scrubber water around the Galápagos Islands….

Ports see substantial discharges, too. Cruise ships dominate those releases, contributing some 96% of discharges in seven of the 10 most discharge-rich ports. Cruise ships typically need to burn fuel in port to continue to operate their casinos, heated pools, air conditioning, and other amenities. Most ports have shallow water, so pollutants are less diluted and can accumulate more rapidly….

Researchers, who are participating in a €7.5 million European effort to study shipping pollution called EMERGE, would like to study how scrubber water affects fish larvae.

But shippers have become hesitant to share samples and data with scientists. “We’re reluctant to give it to organizations which we know have already an established agenda,” says Mike Kaczmarek, chairman of the Clean Shipping Alliance 2020

The ultimate solution is to require ships to use the cleanest fuel, called marine gas oil. In the meantime, 16 countries as well as some localities have banned the most common scrubbers.

Excerpts from Erik StokstadShipping rule cleans the air but dirties the water, Science, May 13, 2021

The International Council on Clean Transportation (ICCT) study, released on April 9, 2021

Scrubbing Sulfur Pollution

From January 2020, the United Nations International Maritime Organization (IMO) will ban ships from using fuels with a sulphur content above 0.5%, compared with 3.5% now.The rules herald the biggest leap in how ships are powered since they switched from burning coal to oil over a century ago, but vessels will still be allowed to use higher-sulphur fuel if fitted with cleaning devices called scrubbers.  Closed-loop scrubbers keep most of the water used for sulphur removal onboard for disposal at port. Open-loop systems, however, remove sulphur coming through a ship’s smokestack with water that can then be pumped overboard.

Years of studies have examined whether open-loop scrubbers introduce into waterways acidic sulphur harmful to marine life, cancer-causing hydrocarbons, nitrates leading to algal blooms and metals that impair organ function and cause birth defects.  The results have largely been inconclusive and the IMO itself has encouraged further study into the environmental impact of scrubbers.

The stated aim of the new IMO measures is to improve human health..  A study in the journal Nature last year found ship emissions with current sulphur levels caused about 400,000 premature deaths from lung cancer and cardiovascular disease as well as around 14 million childhood asthma cases every year.

Singapore and Fujairah in the United Arab Emirates have banned the use of open-loop scrubbers from the start of next year. China is also set to extend a ban on scrubber discharge to more coastal regions. 

Excerpts from Noah Browning, Going overboard? Shipping rules seen shifting pollution from air to sea, Reuters, Oct. 21, 2019

The Price of Banning Dirty Fuels for Ships

A strict sulfur limit for marine fuels is starting in 2020.  US refiners say they have been preparing for the International Maritime Organization’s 0.5% sulfur cap for a dozen years by making billions of dollars of investments to their plants. They also think US oil producers are well positioned to meet new global demand for lower-sulfur fuels.

Despite the industry’s confidence, Gulf Coast refiners are nevertheless skittish about one major wild card.  The January 1, 2020 implementation date comes right in the middle of President Donald Trump’s re-election campaign, and this White House has shown a particular sensitivity to pump prices and their impact on voters.  Trump administration sources told the Wall Street Journal in October that the White House was considering ways to delay the IMO’s 0.5% sulfur cap beyond the long-scheduled January 1, 2020, implementation date. The story alone sent the stock market value of five US refining companies down by a combined $11 billion – hence their skittishness.

Within weeks of the story, trade groups for refiners, oil and gas producers, LNG exporters and steelworkers created the Coalition for American Energy Security to educate White House officials and members of Congress about IMO 2020 and what US industries were already doing to prepare… “The American energy industry is ready to dominate the global market for these new fuels, and timely implementation is critical to achieving that objective.”  said Ken Spain, spokesman for the Coalition for American Energy Security..

Excerpts from Insight from Washington: US refiners worry about White House wild card as IMO 2020 nears, S&P Global The Barrel, Mar. 11, 2019

Cleaning Up Dirty Shipping

Making shipping cleaner is made more urgent by the decision of the International Maritime Organisation (IMO), the United Nations body responsible for the world’s shipping, to reduce the amount of sulphur allowed in bunker fuel from 3.5% to 0.5% by 2020. Sulphur is nasty stuff. When burned, it forms sulphates, which cause acid rain and pollute the air. A paper published in February 2017 in Nature Communications, by Mikhail Sofiev of the Finnish Meteorological Institute, found that the imo’s new rule could stop between 139,000 and 396,000 premature deaths a year.

The trouble is that sulphates also scatter sunlight and help to form and thicken clouds, which reflect solar radiation away from Earth. As a result, shipping is thought to reduce rather than increase man-made global warming—by 7% throughout the 20th century, according to one study. Dr Sofiev’s research showed that this cooling effect could fall by 80% after 2020, with the new low-sulphur standard in place…

The obvious way to offset the loss of sulphur-related cooling is by steep cuts to shipping’s planet-cooking carbon-dioxide emissions. The IMO wants these to fall by half, compared with 2008 levels, by 2050, regardless of how many vessels then ply the seas. But unlike desulphurisation, which is both imminent and legally binding, the CO2 target looks fuzzy and lacks any enforcement mechanism. An attempt to begin fleshing it out, at a meeting of  IMO member states which concluded in London on October 26, 2018 foundered.

One way to cut fuel consumption is to reduce drag by redesigning hulls and propellers. This is happening. In the past five or so years many ships’ propellers have been fitted with tip fins analogous to the turbulence-reducing upturned winglets on aeroplanes.  Further percentage points can be shaved away by smoothing hulls. This means, in particular, stopping barnacles and other creatures growing on them. Tin-based antifouling paints are now banned as toxic to sea life, so paintmakers are returning to an 18th-century solution to the fouling problem—copper.   Hulls can be scraped smooth, too, but restrictions on littering waters with paint chips and species from foreign parts have made such cleaning problematic. This may change, though, thanks to an underwater drone described by its Norwegian maker, ecosubsea, as “a cross between a vacuum cleaner and a lawnmower”. Rather than scour hulls with a metal brush, ecosubsea’s robots blast water at an angle almost parallel with the hull’s surface, which mostly spares paint from abrasion but hits marine growth perpendicularly, and thus hard. 

Many have hopes of returning to wind propulsion, and engineers have devised various modern versions of the sail. None has yet succeeded. A system developed by SkySails, a firm in Hamburg, for example, relied on kites to pull ships along. It was installed on five ships from 2008-11, but proved fiddly to use and maintain…

Some hope to cut marine emissions by employing batteries and electric motors. For transoceanic shipping this looks a long-shot. But local shipping might benefit. Norway, for instance, has started to introduce battery-powered ferries. And a Dutch company called Port-Liner is building electric canal barges for transporting shipping containers. The technology is expensive. Without taxpayer subsidy it would hardly be a runner—a fact also true of the Norwegian ferries.

The problem of shifting emissions around rather than eliminating them also applies to the idea of powering ocean-going vessels using fuel-cells. These generate electricity by reacting hydrogen and oxygen together. Given that electric propulsion more usually disguises emissions than eliminates them, some suggest the most practical approach to reducing shipping’s contribution to global warming is to switch to low-carbon fuel systems rather than conducting a futile search for no-carbon fuels. One alternative is diesel-electric propulsion.  Liquefied natural gas (lng) is another option. 

Excerpts  from Marine Technology of the Future: In Need for a Cean Up, Economist,  Nov. 3, 2018, at 75