Study: Scrubbers Will Have Positive Effect on GHG Emissions

file phot courtesy of Diamantino Rosa
file photo courtesy of Diamantino Rosa

Published Aug 12, 2019 6:29 PM by The Maritime Executive

In a study published in June by Norway’s SINTEF, one of Europe’s largest independent research organizations, Chief Scientist Dr. Elizabeth Lindstad concluded that from well-to-wake the continued use of heavy fuel oil (HFO) with a scrubber is the most environmentally beneficial means of meeting GHG emissions targets.

After detailing findings from research involving full scale testing on a number of newbuild vessels, Lindstad said that: “[Studies] indicate that two-stroke engines with Exhaust Gas Recirculation (EGR) and scrubbers represent the most cost- and GHG-effective way of meeting both IMO Tier 3 NOx rules and the 2020 sulfur cap.”

Her views are based on consideration of the energy consumed, and therefore CO2 released, during the global production of distillate fuels. “With new modern refineries set up to convert crude into higher priced products, high sulfur fuel oil (HSFO) will, from 2020, be delivered from existing refineries where its share of energy consumption can be considered to be next to nothing. The explanation is that the heavy bunker oil coming out from the refinery is the bottom of the barrel. If we acknowledge the lower energy consumption in delivering HSFO and deduct the refining we get nine to 10g of CO2 equivalent per MJ for HFO, rather than 13 to 15 of CO2 equivalent per MJ for LSFO/MGO.”

Lindstad also believes that emissions abatement rules need to be reviewed to consider pollution problems in different areas. “To meet climate targets, i.e. reduce global GHG emissions, we can no longer afford to have standards that are strict in areas where we do not have local pollution problems, while areas with high pollution may need even stricter rules than today.”

The industry body Clean Shipping Alliance 2020 (CSA2020) has welcomed Lindstad's work. Executive Director Ian Adams said the industry has long realized that there is an energy penalty differential in the production of fuels. “Using higher sulfur fuels with an exhaust gas cleaning system will have a beneficial impact on the global reduction of sulfur and nitrogen oxides emissions and also on greenhouse gas (GHG) emissions.”

According to Adams, there is also a significant benefit from reduced particulates in emissions. “With reduced particulates in exhaust emissions of 75 percent or more, the combination of dramatically reduced SOx and particulates makes a big difference in improved air quality and lower health risks,” he said.

“This study provides further scientific evidence that both local SOx and NOx to air and global CO2 emissions will be reduced by the expanded use of HFO with exhaust gas cleaning systems in the marine fleet, with benefits to the marine and port environments and, of course, human health.”