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North P&I Club debunks exhaust gas cleaning systems

20 Jul 2018

Alvin Foster, Deputy Director (Loss Prevention) at the North P&I Club asks Don Gregory and Mark West of the Exhaust Gas Cleaning System Association about the finer points of scrubber operations and how the technology allows shipowners to meet the upcoming IMO 0.5% sulphur cap by 2020:

Choosing the best option to comply with the sulphur cap will be a gamble. The economic success of a shipowner’s choice depends heavily on future fuel prices in 2020 and beyond.

If the price difference between high sulphur residual fuels and 0.5%S distillates reaches $400 per tonne in 2020, as predicted by some market analysts, then installing exhaust gas cleaning systems (EGCS) looks like a very attractive option. 

Much has been said and written about EGCS – commonly referred to as ‘scrubbers’ – and whether it is an environmentally sound solution. Is putting the SOx into the sea any better than releasing it into the atmosphere? 

The public perception of the “greenness” of scrubbers may well be different to the reality. To help us decide on what is myth and what is fact, North asked Don Gregory and Mark West of the Exhaust Gas Cleaning System Association (EGCSA) to take part in a short Q&A. 

The following are the opinions of the EGCSA and do not necessarily reflect the views of North. 

Q. Doesn’t an EGCS merely move the pollution from the air into the sea?
A. This is a common misconception – scrubber wash water removes and converts sulphur oxides from the exhaust gases so they are discharged in the wash water as harmless sulphate. After sodium and chloride, sulphate is the most common ion in seawater. Even if all of the sulphur in all of the world’s petroleum reserves were to be scrubbed, the increase in ocean sulphate would be infinitesimally small. Scrubber wash water discharges are also continuously monitored and subject to strict discharge limits. Various studies have concluded that any reduction in pH from scrubbing, will be insignificant when compared with that resulting from increasing atmospheric CO2 absorbed by the oceans. 

Also, open loop scrubbing has been used for years by coastal power stations and by oil tanker inert gas (IG) systems when in port without environmental issues. 
Taking the holistic view, scrubbing enables the use of residual fuel to continue, which means the energy needed for producing distillate fuel and resulting CO2 emissions can be greatly reduced. 

Q. What about the numerous anecdotes about EGCS being unreliable and requiring a lot of maintenance?
A. This may have been the case some years ago before exhaust gas cleaning became widespread. However, scrubbing is an established technology. There have been some reports of pipe failures due to using incorrect materials or incorrect coatings. The key to successful EGCS is extremely professional project management and high quality installation teams. EGCS are designed for the life of the ship. 

Q. Can we expect laws – international, regional or domestic – that will eventually control or ban the discharge of EGCS effluent (particularly in confined waters and ports)?
A. IMO already requires that the wash water parameters of pH, polycyclic aromatic hydrocarbons (PAH) and turbidity are continuously monitored and the results logged against time and ship’s position. 

There are a few ports that have prohibited the use of open loop scrubbers in their waters. But there is no evidence to justify the prohibition. There are many examples of land based scrubbers operating for decades without measurable impact on sediments or the surrounding waters. It is very much an emotional reaction. 

Q. Are you confident that refineries will continue to produce cheap high sulphur residual fuels post-2020?
A. Yes – there is no doubt that refiners are worried about the disposal of residues come late 2019 with the switch to 0.5%S fuel. The worst case scenario is the high sulphur fuel falls below the price of coal.

Q. If using closed-loop and hybrid scrubber systems, what happens with the chemical waste? Is it disposed in an environmentally sound manner?
A. The scrubber guidelines require that waste generated by closed loop EGCS is delivered to shoreside reception facilities. It cannot be discharged to the sea or incinerated onboard. 

Q. If the EGCS malfunctions in service, is the vessel in breach of MARPOL Annex VI? 
A. The key advice that EGCSA has received is that ship operators should be open and advise flag and coastal/ port state without delay of the issue and remedial action that is being taken. In the event of a problem preventing system operation, the ship would not be considered as being in immediate breach of the regulations because non-compliance would be unintentional and the provisions of regulation 3.1.2 of MARPOL Annex VI would apply.  

If EGCS operation is not possible, the ship is advised to change over to compliant fuel. However, if there is no compliant fuel on board, the ship should be allowed to complete the current leg of its voyage without deviation and then carry out repair works or bunker compliant fuel. 

Q. Is it too late to order and install an EGCS on a vessel before 2020? 
A. It is understood that most of the EGCSA members cannot now deliver until after 2020. There are some bottlenecks such as availability of laser measurement surveyors and experienced installation teams. However, we understand one particular yard in Korea has recently quoted 19 days for complete installation. As things stand, high alloy steels required for manufacture are still available in sufficient quantities. 

Published: 20 July, 2018

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