A McGill University study recommends cold-climate cities increase their electric bus fleets and expand charging capacity so vehicles can be charged slowly, a process that draws less power from the grid than fast charging.
Efficient energy use is particularly important in cold weather, when electric batteries drain more quickly and use more energy than in milder conditions, they noted.
The researchers said their approach could help these cities fully electrify transit systems, eliminating reliance on diesel.
"Anyone can operate an electric bus fleet, but minimizing operating and environmental costs should be a concern, because everyone is paying for these systems," said Luis Miranda-Moreno, an associate professor in the Department of Civil Engineering. "We are trying to help bring awareness and build tools that reduce costs."
The study is the first to model electric bus operations at the municipal level in winter conditions.
Digital model reveals energy consumption
The researchers created a digital model simulating Quebec City's electric bus network and infrastructure. This allowed them to see how buses, rider behaviour and other traffic interacted.
From this data, they estimated the buses' energy consumption. They then considered various weather conditions and assessed the impact on the network's performance, finding that winter increased energy demand by 30 per cent.
The team also considered two charging scenarios: fast charging, in which more powerful chargers recharge buses quickly but demand more power, and slow charging, wherein charging is less power-intensive but requires more time.
The researchers' optimization tool then determined how to best reduce energy consumption while making fleet operations feasible in the real world. Possibilities included fine-tuning bus fleet size and charging schedules, as well as adjusting battery thresholds. Their tool demonstrated that slower charging, an increased fleet size and more chargers would demand less power and be more cost-effective than current approaches.
"In Canada, there is no one-size-fits-all approach to fleet electrification. This type of analysis helps cities understand how winter conditions affect electric bus operations, charging needs and grid capacity, so fleet planning and power infrastructure can be aligned," said Jônatas Augusto Manzolli, lead researcher and a Postdoctoral Fellow in the Department of Civil Engineering.
The researchers noted that this type of tool could be critical not just for managing climate-change impacts, but for cutting operating costs, given that transit agencies often run deficits. Future studies will assess transit operations for Montreal and Ottawa.
About this study
"Planning resilient electric bus operations in cold regions: An agent-based simulation-optimization framework," by Jônatas Augusto Manzolli, Alessandro Vissarios D'Apice, Luis Miranda-Moreno et al, was published in Applied Energy.
Funding was provided by the Government of Canada's Environmental Damages Fund and the Fonds de recherche du Québec - Nature et technologies.
