Life Cycle Assessment of Hydrogen and Diesel Dual-Fuel Class 8 Heavy Duty Trucks

Significance 

Recent climatic changes have clearly demonstrated the impacts of global pollution. As such, counteractive measures have been put in place through the United Nations Framework Convention on Climate Change in a bid to encourage different countries to mitigate the current climate situation. Fast forward, diesel engines are among the leading emitters of greenhouse gases. This does not look good for heavy-duty trucks; the main consumers of diesel. Specifically, class 8 tractor-trailer combinations for freight, are a major contributor to the total greenhouse gas (GHG) emissions in transportation systems worldwide.

Diesel fuel vastly dominates this market due to its relatively low operating cost. Nevertheless, both GHG and air pollutant emissions from diesel combustion are significant. In fact, literature has it that diesel engines are the source of very fine particles ranging from 0.01 to 1 µm that pose health hazard to life. This therefore raises doubts about the long-term sustainability of this mode of transportation. A possible short-term opportunity to address this problem is to blend diesel with hydrogen by retrofitting existing fuel injection systems and fuel storage onboard the trucks.

In this context, a team of researchers at Simon Fraser University comprised of Drs. Mohamed El Hannach and Pouria Ahmadi and Professor Erik Kjeang from the Fuel Cell Research Laboratory (FCReL), School of Mechatronic Systems Engineering together with Laura Guzman and Simon Pickup at Hydra Energy Corporation conducted a life cycle assessment aimed at evaluating the overall environmental and economic impacts of implementing hydrogen and diesel dual-fuel solutions in heavy-duty trucks. To this end, they developed a tool called Fleet Life Cycle Assessment (LCA) in order to realize their goals. Their work is currently published in International Journal of Hydrogen Energy.

Following a description of the LCA approach and the specifics of the Fleet LCA tool, the implemented methodology was applied to a case study of converting a fleet of heavy-duty trucks operating in the proximity of an existing waste hydrogen source in British Columbia, Canada. Specifically, LCA metrics were evaluated for 200 trucks over a period of 20 years and for different values of diesel displacement ratios and waste hydrogen pricing.

The authors mainly reported that there was a significant reduction in emissions, proportionally to the diesel displacement ratio. Pleasingly, the use of hydrogen fuel was also shown to provide potential cost savings in this highly cost-sensitive application for hydrogen pricing below C$4/kg.

In summary, a novel LCA approach was applied by Professor Erik Kjeang and the research team to a case study that involved the partial substitution of diesel with waste hydrogen in a fleet of class 8 heavy duty trucks. Overall, excellent results were obtained with regard economic and environmental considerations. Altogether, waste hydrogen available at low cost can facilitate immediate emission reduction and operational cost savings for existing truck fleets, and act as an economical bridge solution for sustainable heavy-duty freight.

Reference

Mohamed El Hannach, Pouria Ahmadi, Laura Guzman, Simon Pickup, Erik Kjeang. Life cycle assessment of hydrogen and diesel dual-fuel class 8 heavy duty trucks. International Journal of Hydrogen Energy Volume 44, Issue 16, 2019, Pages 8575-8584.

Go To International Journal of Hydrogen Energy Volume

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