Wednesday, September 23, 2020

Exhaust Cleaning Scrubbers are Preferable to Low Sulphur Fuel Claims New Report

Marine Fuels Under the Spotlight
Shipping News Feature

WORLDWIDE – It seems the debate on the value of 'scrubbers', those devices which render emissions from ships engines less harmful, is set to continue with the release of a report published by CE Delft, ‘Comparison of CO2 emissions of MARPOL Annex VI compliance options in 2020’.

The purpose of the study was to quantify the climatic impact of scrubbers compared to low sulphur fuel oil. In practice, there are two options for achieving compliance with MARPOL Annex VI Regulation 14. The first is using an exhaust gas cleaning system (EGCS), a ‘scrubber’ in combination with fuel oils with sulphur content higher than 0.50% or 0.10%. The second is burning fuel oil with a sulphur content of 0.50% / 0.10% or less.

Both options result in an increase of well-to-wake CO2 emissions. Operating an EGCS requires energy from engines running on fuel oil, thus generating CO2. Emissions associated with manufacturing scrubbers and discharge of wash water during operation are also factors. Desulphurisation in a refinery requires hydrogen, generally produced from methane, requiring energy and emitting CO2 during the process.

The report concludes that the environmental impact of EGCs will be less than that of low-sulphur marine fuel. It notes that CO2 emissions associated with producing and installing an EGC system are small compared to those generated when operating the system. The CO2 emissions are mainly related to the energy demand of the system’s pumps, which typically result in a total increase in CO2 emissions of between 1.5 and 3 %.

By contrast, with de-sulphurised fuels the overall CO2 footprint increase is a result of the refining processes. Theoretical calculations range from an increase in CO2 emissions of 1% to as much as 25% when removing the sulphur content of the fuel. The report states that while the lower figure is not in fact physically possible, the higher percentage increase is applicable only to a quality of fuel that is too high for marine applications.

The conclusion, therefore, is that the CO2 emissions associated with the production of low-sulphur marine fuels will be between these extreme values, as illustrated in the image shown above. Research has indicated that greenhouse gas (GHG) emissions from shipping have increased by more than 10% in the last five years. These emissions are projected to increase by up to 50% by 2050, which means that if the International Maritime Organization’s goal to significantly lower the industry’s GHG emissions is to be achieved, scrutiny of all aspects of the shipping industry and its processes is necessary.

Norwegian group Yara Marine and Finland’s Wärtsilä have both endorsed the findings of the report, hardly surprising as the pair commissioned the work in partnership with Alfa Laval. Those three parties of course all have vested interests in the future of the technology. Critics will doubtless point to the ongoing arguments of closed loop versus open loop scrubbers and how the extracted waste is dealt with. Jasper Faber, Project Manager at CE Delft however was unequivocal saying:

“This study provides a comprehensive overview of the climate impacts of different options to reduce sulphur emissions. It shows that in many cases, the carbon footprint of using a scrubber is lower than low-sulphur fuels.”

Kai Låtun, Director, Yara Marine Technologies backed the findings saying ‘there is no doubt that using compliant fuels, all things considered, will result in three to five times higher CO2 emissions than using HFO as fuel in combination with scrubbers’, whilst Jan Othman, Vice President, Exhaust Treatment at Wärtsilä commented:

”Wärtsilä has consistently demonstrated its commitment to minimising the marine sector’s carbon footprint. This shows not only in our products and systems, but also in our manufacturing and production processes. We are delighted that this independent report confirms that when taking all things into consideration, our EGCs create less CO2 emissions than the use of sulphur-compliant fuel.”