Christopher Fee, General Manager Environment & Sustainability bei Oldendorff Carriers und Director der Clean Shipping Alliance 2020 (Foto: Oldendorff Carriers)
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Does anybody remember Y2K? It was the late nineties, and due to an extensive computer programming glitch that was expected to cause widespread chaos as the year changed from 1999 to 2000.

Interested parties started spreading panic and fear, in an attempt to convince the world that the turn of the millennium would result in millions of computers [ds_preview]used by the financial, energy and transport sectors crashing at the stroke of midnight on December 31, 1999, and havoc and mayhem would ensue. Although there was an immense outcry about the potential implications of this change, in actuality, not much eventually happened. While there were a few minor issues once January 1, 2000, arrived, no massive malfunctions or breakdowns occurred. Some say that the smooth transition was attributable to the huge efforts undertaken by business and government authorities to correct the glitch in advance, while others say that the problem was over-exaggerated to begin with and would not have caused considerable problems in any case.

One could argue that we were seeing the same unnecessary and overdramatised panic and scepticism occurring within the maritime industry in the lead up to IMO’s 2020 Global Sulphur Cap. Whereby, thousands of ships would be required to switchover to low-sulphur fuels as 2020 neared, along with the more widespread uptake of exhaust gas cleaning systems (scrubbers). 2020 has now finally arrived, and so has IMO’s Global Sulphur Cap.

We will find out…

As we celebrate the beginning of a new decade, the maritime industry can also celebrate achieving a huge step in playing its role in reducing its environmental footprint by drastically improving local and global air quality. Over the next few weeks we will find out whether all these months reading and hearing about major shortages of IMO 2020 compliant fuels, and catastrophic engine failures due to unstable, incompatible and insufficiently tested low-sulphur fuels, were indeed justified, or were simply as overstated as the claims of the Y2K bug scaremongers 20 years ago.

As this piece focusses on scrubbers, I will do my best to refrain from too much mention of fuels, unless where absolutely essential. However, what is necessary and important to talk about is air quality and the full picture of well-to-wake emissions. As the debate around these emission abatement systems will likely continue within the maritime community and trade press for many more months to come, the overall net environmental impact of scrubbers needs to be considered in order to come to a fair conclusion. In the interest of objectivity and to remain unbiased, it is of utmost importance that we refer to the numerous comprehensive independent scientific studies, to ensure that the facts prevail over the fiction, and that a transparent conclusion to this somewhat contentious topic is reached.

So, with that in mind, let’s do precisely that and refer directly to the fundamental underlying science of three separate independent studies. Before we do so, let’s quickly take a look at where the technology came from and what it has helped society achieve thus far. Scrubbers are a diverse group of air pollution control devices that can be used to remove some particulates and/or gases from industrial exhaust streams. The first scrubber was designed to remove carbon dioxide from the air of an early submarine, the ‘Ictineo I’, a role for which they continue to be used today.

Scrubbers had been built in the United Kingdom in the 1930s, but it wasn’t until 1967 that the first full-scale scrubber at a coal-fired power plant began operating in the United States. In 1977, U.S. Congress passed a new Clean Air Act essentially mandating that all new coal-fired power plants install scrubbers to remove sulphur emissions and lessen the formation of acid rain. Scrubbers were first used onboard ships for the production of inert gas to improve safety in oil tanker operations by mitigating the risk of explosions. Since around 2006, scrubbers have been fitted on cruise ships and ferries to help those owners and operators comply with stricter regional sulphur emission regulations. Since around 2017, other types of ships have been installing scrubbers to help them achieve compliance with the global sulphur limit which came into force a couple of days ago. Scrubbers have therefore played an important role in improving air quality throughout the 21st and much of the 20th century.

If they had not been installed in power-plants, refineries and other land-based industrial applications, our cities would be a lot smoggier than they are today and much more acid rain would have fallen in our lakes and rivers. In 2012, the Danish Ministry of the Environment’s Environmental Protection Agency (Danish EPA) published a report from a study they had undertaken in order to obtain a more detailed assessment of scrubber wash water, the results of which could then be added to the ongoing international evaluation of criteria for wash water from these systems. The report, titled ‘Assessment of possible impacts of scrubber water discharges on the marine environment (Environmental Project No. 1431, 2012)’ concluded that, compared to environmental acceptability levels at the time, the releases from scrubbers could be expected to be considerably below the levels of ecological concern.

Along with emphasising that the impact of wash water from scrubbers was negligible, the Danish EPA’s report also made a very thorough analysis, comparing maximum concentrations that may occur as a result of extensive use of scrubbers to the European and Danish water quality standards. The study considered an extreme-case scenario, whereby an assumption was made that all vessels would be fitted with open-loop scrubbers if commercially viable, demonstrated that ambient concentrations should remain below European and Danish environmental quality standards, hence the study did not identify any concerns with the widespread use of these systems.

In January 2018, Concawe published a report titled ‘Environmental Impacts of Marine SO2 Emissions (Report No.1/18)’ where they presented some interesting and compelling conclusions. Scrubbers performed exceptionally well in comparison to low-sulphur fuels on a so-called well-to-wake emissions basis (i.e. taking into consideration the emissions generated from pumping the crude oil out of the ground, transporting the unrefined product, refining it, transporting to refined product to the vessels and combustion on board). The study concluded that removing sulphur from fuels will result in increased CO2 emissions from refineries related to the additional processing, including hydrogen treatment, and that removing SO2 from a ship’s exhaust by use of a scrubber offers an alternative with a lower overall greenhouse gas (GHG) impact.

It then goes on to say that if vessels make use of scrubbers, it will result in lower overall CO2 emissions versus desulphurisation of the fuels in refineries. When the life cycle energy consumption of the different fuels and chemicals is taken into account, removing SO2 from exhaust gas has been shown to be less energy consuming than the alternative of removing the sulphur from fuels in refineries. Desulphurization of fuels requires a lot of energy, as one needs hydrogen, high temperatures and high pressures to do so. Concawe estimated that significant CO2 emission savings can be achieved by utilising scrubbers.

In their report, they calculated that a 100% scrubber uptake scenario would avoid a 17 million tons per year increase in CO2 emissions from EU refineries, partially offset by 8 million tons per year increase in CO2 emissions from the energy needed to run the scrubbers, resulting in a net saving of 9 million tons of CO2 emissions per year. In respect to the wash water, the report concludes that while at first sight, a scrubber may be seen as a device that moves pollution from air to water, the discharge of sulphate into the ocean does not result in an environmental concern because the ultimate fate of atmospheric SO2 emissions, whether manmade or from natural sources, is conversion to sulphate salt, and oceans are a large sink of naturally occurring sulphate salts.

In fact, sulphate is being constantly generated in immense quantities through seabed volcanic activity. In October 2019, the well-respected and renowned independent research and consultancy organisation, CE Delft in the Netherlands, published a report titled ‘The impacts of EGCS washwater discharges on port water and sediment (Publication code: 19.4I09.141)’. The aim of the study was to provide a method for evaluating the impacts of using open-loop scrubbers in ports and to test the methodology conservatively in a series of model ports, using empirical data of almost 300 washwater samples taken from several vessels fitted with such systems fitted.

The data collected were used as inputs for the Marine Antifoulant Model to Predict Environmental Concentrations (MAMPEC Model) in order to calculate the predicted environmental concentrations (PEC) of target substances that open-loop scrubber operations may contribute to the background concentrations of target substances in port water and sediment. Their results show that equilibrium concentrations of metals and PAHs in the water and the five year sediment concentrations depend predominantly on the hydrodynamic exchange of the port water with the surrounding waters. As an example a port with a wider port entrance will lead to lower concentrations than an enclosed port with a narrower port entrance. Additionally a river port which is not enclosed and has a continuous water exchange will lead to lower concentrations than an enclosed port with a wide port entrance.

A reference scenario has been defined in which just over 40 tonnes of fuel is consumed per day by ships at berth operating open-loop scrubbers. This level of fuel consumption is equivalent to over 28 small bulk carriers, or 6 large container ships, or two medium-sized cruise ships at berth for every day of the year, or any ship size and type combination which uses just over 40 tonnes of fuel per day in port in combination with an open-loop scrubber. For the reference scenario, the modelled equilibrium concentrations of metals and PAHs in the water have been compared with European water standards that are applicable from 2021 onwards (in other words, even more stringent standards than are currently in force). In most ports and for most substances, the increase in concentrations is less than 0.1% of the allowed limits. In ports with low hydrodynamic exchange, and especially for a few Polycyclic Aromatic Hydrocarbons (PAHs), the increase in concentration can increase to 0.6% of the allowed limits.

A portion of the substances discharged by open-loop scrubbers in ports ends up in the port sediment. Assuming a zero concentration to begin with, the modelling shows that for the Standard OECD-EU Commercial Harbour the increase in sediment concentrations of metals and PAHs after five years is less than 0.3% of the referenced standards for dredged materials. The modelling results also suggest that the impacts of using open-loop scrubbers are small in relation to the agreed water quality standards for 2021. IMO has published guidelines for the certification of scrubber systems, covering amongst others the allowable sulphur content in emissions, and limits on the relevant components that may be present in the wash water prior to discharge.

Although the document is described as a guideline, it is given mandatory effect under MARPOL Annex VI, Regulation 4 and also the EU Sulphur Directive (2012/33/EC). These guidelines specify the requirements for the testing, survey and certification of scrubbers through the establishment of limits for pH (acidity), PAHs, turbidity (colour/hue) and nitrates in the wash water. Several reports, including some of those mentioned earlier, have considered the environmental impact of scrubbers in marine environments, and all concluded, or referred to literature stating, that the substances discharged with the wash water will not lead to an exceedance of the applicable water quality standards. Conclusively, it is imperative that the overall net environmental impact of any proposed solution to environmental regulatory compliance, whether it be low-sulphur fuels (VLSFO/MGO), LNG or scrubbers, be analysed on a well-to-wake basis to ensure that a fair and comparable assessment is made and that the emissions from the entire lifecycle is taken into account (in other words, we must compare apples with apples).

Air pollution is a massive problem, and SOx scrubbers are one of many emission abatement solutions currently available to help combat this issue, which has profound impact on both human health and the natural environment. Air pollution is often referred to as the invisible killer because, although it may not always be visible, it can be deadly. In fact, according to the World Health Organisation (WHO), 92% of the world’s population lives in places where air pollution levels exceed the WHO Ambient Air Quality Guidelines. Furthermore, 1 in 8 premature deaths in the world are linked to air pollution – this resulted in more than 7 million deaths in 2012 alone.

To give you an idea of how serious the air pollution issue is, the WHO figures show that 29% of deaths from lung cancer, 24% of deaths from stroke, 25% if deaths from heart disease and a very-worrying 43% of deaths from lung disease are attributable to air pollution. I think we can all agree that we have a huge challenge to face as a society. SOx scrubbers can’t solve all these problems, but they can certainly help improve the situation since they are not only very effective in capturing and removing up to 99% of SOx, but in doing so, also capture and remove up to 94% of particulate matter, up to 60% of black carbon, up to 40% of PAHs and approximately 5% of NOx.

So, although scrubbers might not be the long-term solution, they are a perfectly acceptable and sensible short- to medium-term one as they remain a very convenient and effective outlet for the inevitably produced high-sulphur fuels that are generated as a byproduct by many older, less technologically-advanced refineries – otherwise, where else would this go? Older refineries cannot install billion-dollar hydro crackers and coking units overnight, it can take up to 8 years to design, approve, manufacture, install, test and fully commission these complex refining systems. In the meantime HSFO will continue to be produced and if the ship owners, whose vessels’ engines have been designed and built to run on this byproduct are not permitted to use it in combination with scrubbers, we can only guess who it will be sold to and how it will end up being disposed of. I trust that this short piece was of interest and insightful to you, the reader. I urge you to refer yourselves to the full reports from the studies mentioned, which are available freely on the public domain.