Scrubbers – An economic and ecological assessment

CE Delft has analysed the economic and ecological aspects of using scrubbers as a means for ships to meet the SECA fuel sulphur requirements. The study was launched in Hamburg on 13 March during a seminar organised by the German NABU (Nature and Biodiversity Conservation Union), which commissioned the study. The study focuses on the current and future market, the ecological impact of increased use of scrubbers in coastal areas and the business case for ship-owners.

The number of scrubbers installed on vessels has increased significantly in recent years. About 80 scrubbers are currently installed, most of which are hybrid or open-loop scrubbers. At the time of writing, the number of units ordered stands at approximately 300. Although the IMO wash-water criteria for scrubbers are generally met, if there is insufficient dilution, scrubbers may have a negative impact on the marine environment in the form of acidification, eutrophication and accumulation of hazardous hydrocarbons and heavy metals, particularly in ports and coastal areas. The long-term impacts of use of open-loop scrubbers, especially in vulnerable coastal areas with reported moderate water quality, therefore needs to be systematically investigated by measuring and modelling water quality. Based on the results, it should be assessed whether scrubbers can be used in accordance with the European Water Framework Directive and Marine Strategy Framework Directive, which set maximum concentrations for certain hazardous pollutants, prohibit deterioration of water quality and aim to achieve ‘good environmental status’, respectively.

It is hard to draw firm conclusions on the profitability of using scrubbers, as this depends on the vessel’s operational profile, the differential between HFO and MGO prices, and the time sailed in SECAs. Between January 2014 and February 2015 the HFO/MGO fuel price differential ranged from 240 to 300 $/ton. Scrubbers are more often profitable when this difference in high than when it is low.