Scrub up

Scrubbers are designed to remove sulphur from a ship’s emissions, thereby enabling the vessel to comply with the IMO 2020 sulphur cap regulations while still using high sulphur fuel oil (HSFO). HSFO is inherently less complicated to produce and faces less competing demand from industries on land and the post-IMO 2020 shipping industry than very low sulphur fuel oil (VLSFO). This means that a scrubber delivers savings because an owner can bunker significantly cheaper fuels.

But 2020 was a difficult year for scrubber owners.

In late 2019, the difference in price between HSFO and VLSFO peaked at over $300 per tonne. This spread began to narrow from January 2020 and dipped below the symbolic $100 per tonne figure in mid-March. For much of the rest of the year, this figure remained resolutely in the mid-double digits. This elongated payback times for scrubber owners, who had made multi-million-dollar investments.

In 2021, the dynamic has once again changed. Many of the conditions that squeezed the spread have abated, while demand for distillate fuels has increased as the global land-based economy has tentatively began its recovery. The spread has seemingly now settled at the low three figure mark, and scrubbers once more represent rapid savings for owners.

Scrubber regulations are fragmented
As scrubbers have become more profitable for more types of vessel, there has been an increased understanding of the regulatory risks that owners must deal with, and there’s an increasing number of different standards applicable to different territories. This kind of fragmentation naturally creates challenges for shipowners and operators.

One of the key areas of regulatory risk relates to the monitoring of scrubber wash water effluent. This water is used to treat the exhaust gasses of a vessel, and is then released into the ocean – if everything is working as it should, this water is entirely inert and will have no impact on the marine environment.

However, technical issues could contaminate this water and cause severe pollution issues. This is why all international and regional regulations on scrubbers require that scrubber wash water is continually monitored to ensure that its PH, temperature, turbidity and polycyclic aromatic hydrocarbons (PAH).

PAH measurements pose a particular problem for scrubber owners, who must contend with different measurement standards across different jurisdictions. Some jurisdictions require only limited measurement, while others such as the US require these carcinogenic by-products of unburnt or improperly burnt fuel must be measured through a full spectrum analysis.

The IMO is seeking to harmonize rules on PAH testing and is currently collecting evidence in preparation for new rules. This will eventually simplify compliance for shipowners but creates a risk for owners investing in machinery today, who need to be sure that their systems will remain compliant in the long term.

Future-proofing installations through accurate monitoring
Given the IMO’s mandate to harmonize testing approaches and likelihood of regulatory change, the only way to ensure confidence in the future compliance of a scrubber is to use an accurate wash water monitor that provides full-range PAH analysis today, integrated as part of the scrubber system design. This not only provides shipowners with confidence that their system is working as intended, but means that their system will already meet the higher standards today.

Chelsea’s Sea Sentry system provides this level of analysis. Certified by DNV-GL and ClassNK and trusted by shipowners around the world, Sea Sentry has been installed on hundreds of vessels. Importantly, it is designed to provide this level of analysis with an easy-to-use interface and a heightened level of automation – ensuring that maintenance is kept to a minimum so that no additional crew training is required to deliver accurate results.

The economics have swung in favor of scrubbers once more in 2021, and wider economic and geopolitical factors mean that it is likely that the VLSFO premium will remain substantial. Many shipowners will now be looking at scrubbers as a cost-efficient compliance solution, but it is important that they also look at their wash water monitor – to ensure that their system remains compliant for the long term.

Adam Jolliffe is Senior Sales Manager – Maritime, at Chelsea Technologies, which designs and manufactures environmental monitoring technology to make the world safer, cleaner and  smarter. Working across shipping, marine science, water quality, defense and industrial process control, Chelsea has built unrivalled specialist expertise over 50 years in operation. Chelsea’s pioneering technology is helping to gauge shipping emissions, explore the oceans, create healthier fisheries, optimize crop spraying, improve production efficiency, and even monitor microplastics and climate change