Making the best measurement of black carbon emissions in marine transportation to help drive their reduction. That's what the Black Carbon Metrology group at the National Research Council of Canada (NRC) does.
Climate change is on everyone's radar, and governments across the globe are working towards finding evidence-based solutions to ensure a better future for our planet. Black Carbon, the second biggest contributor to global warming after carbon dioxide (CO₂), exacerbates global warming in snow-covered territories by darkening their surface.
Black carbon, a component of fine particulate matter formed mainly by the incomplete combustion of fuels in internal combustion engines, much like greenhouse gas (GHG) emission, has a warming effect on the atmosphere as it absorbs heat. When falling back to Earth, it darkens the snow and ice surfaces, and absorbs the sun rays turning them into heat, and accelerates the melting of snow, and ice. That being said, black carbon emissions also have a huge impact on our health. Its minuscule size that can easily find its way deep into our lungs, causing cardiovascular and respiratory diseases.
The research team composed of Dr. Joel Corbin, Brett Smith, Dr. Prem Lobo, and Dr. Stéphanie Gagné from the Black Carbon Metrology group at the NRC, Prof. Patrick Kirchen, David Sommer, Prof. Steven Rogak, and Una Trivanovic from the University of British Columbia's mechanical engineering department, and Prof. Wayne Miller, Weihan Peng, and Dr. Jiacheng Yang from the Center for Environmental Research and Technology at the University of California Riverside set out to measure black carbon emissions from a commercial ferry belonging to Seaspan Ferries equipped with the latest engine technology using liquefied natural gas (LNG) instead of diesel. This marine fuel is becoming increasingly popular due to regulatory pressures and concerns for the environment; however, we have very little data available of the emissions it creates.
The good news? The multi-institution team, coordinated by Dr. Gagné, was able to measure gaseous and particulates emissions, including black carbon. This research was conducted in order to inform policy discussions for the International Maritime Organization (IMO), as part of a project supported by Transport Canada.
The IMO had 2 important questions on its agenda:
- What are the different black carbon instruments capable of measuring black carbon emissions from ships using a wide range of fuels, including LNG and diesel?, and
- Is using LNG as a fuel an appropriate measure to reduce black carbon emissions from ships?
Because of the team's expertise, the tricky humid LNG exhaust emissions were conditioned to enable the best black carbon measurements and, as a result, the instruments were in surprisingly good agreement, which is impressive given they are based on very different measurement principles. The results also showed that this engine, was emitting 37 times less black carbon with LNG than it did with diesel.
"It was very exciting to see how our measurements have a direct application helping a Canadian company assess and improve their environmental performance. At the same time, we got to study the origin of black carbon and other particulate emissions from the latest dual-fuel marine engine technology," relates Dr. Stéphanie Gagné, lead researcher.
The engines they tested belonged to Seaspan Ferries. The team also measured gaseous emissions including carbon dioxide (CO₂), methane (CH₄), nitrogen oxides (NOₓ), sulphur oxides (SOₓ), and carbon monoxide (CO).
The measurements campaign on a Seaspan Ferries vessel in British Columbia determined that the use of LNG instead of diesel decreased black carbon emissions by 97%, and decreased particulate matter emissions by 92%. It was also beneficial for the local air quality and reduced CO₂ emissions by about 20%.
"Seaspan has been working with the NRC since early 2018 in order to gain a greater understanding of the emissions related to our new LNG/Hybrid vessels that operate in British Columbia. In this work, specifically the characterization of particulate matter, we have been able to gain a greater understanding of black carbon and other emissions from our engines, as well as the impact that the recommended changes to our operation will have on our emissions profile. We have used this work in order to modify our operations, and minimize our GHG and particulate emissions. Without the help of the NRC, we would not have been able to reach these conclusions and make such meaningful changes," said Harly Penner, Director, Fleet Engineering and Vessel Development at Seaspan Ferries.
The not so good news: LNG introduces methane emissions. But the team found that the methane emissions can be reduced by technological and operational solutions. They were able to make recommendations to the vessel owners for optimizing their operations to reduce health and climate impacts. The vessel owners have adopted most of the recommendations.
Now that the issue of methane emissions related to LNG use has been brought to light, ship owners are putting pressure on engine manufacturers to reduce these emissions at an engine design level, to ensure that LNG is a green choice across the board.
The recommendations made by the research team include connecting the marine vessels to shore power when at berth, turning off 1 of the 2 engines when 1 engine can provide enough power, therefore increasing the load on the remaining engine and decrease the unburnt methane and, finally, using cylinder deactivation at low loads, when the methane emissions are the highest. Cylinder deactivation is when some of the cylinders are shut down to increase the load shared by the remaining cylinders. Turning off up to 3 cylinders (out of 9) means that each working cylinder will carry a larger load and burn through more methane, reducing the methane escaping into the atmosphere.