Search

The high cost of battery electric buses (BEB), driven by battery and infrastructure costs, is a key factor limiting their market penetration. These costs are determined by the choice of battery size and charging infrastructure. In addition, the electrification of public transit buses raises questions regarding the fleets' punctuality toward their pre-defined schedules, due to the possible schedule delays resulting from BEB charging. In this context, this paper presents a methodology to assess the techno-economic performance of BEB fleets for different battery sizes and charging infrastructures and strategies. The proposed methodology is based on a detailed total cost of ownership (TCO) model considering purchase, operation, maintenance, and infrastructure costs. In addition, a punctuality index (PI) is introduced to quantify schedule delays due to BEB charging events during the day. A case study is used to illustrate the model and results show that overnight charging has the highest TCO, 13% higher than the TCO observed during end-line or opportunity charging. Moreover, a clear trade-off is observed between TCO and BEB punctuality to their schedule. Results show that there is significant room to reduce the TCO of BEB while respecting their operational constraints, by co-optimizing the battery size and charging infrastructure. [ABSTRACT FROM AUTHOR]

With the deployment of battery electric buses (BEB) increasing worldwide, proper battery sizing becomes more critical for operators as it dictates bus driving range and costs. In this paper, we present a battery sizing framework based on comprehensive energy needs assessment for BEB. The bus operating conditions are first defined for different types of bus service (City, intercity, shuttle, regional, rapid-transit). Then, BEB energy consumption is evaluated using a comprehensive energy model developed by the authors. Finally, the required battery size is estimated for different types of charging infrastructure. Modeling results show that BEB energy consumption is sensitive to bus service type, ranging widely between 2 and 4.6 kWh/km, and that intercity buses require the largest battery size (320–680 kWh). A practical finding for operators from our Paris case study is that city bus batteries are unnecessarily oversized to accommodate a typically small fraction of trips in rare extreme cold weather conditions. • Study proposes a battery sizing framework for electric buses. • Evaluates energy consumption and battery sizing for different types of bus service. • Tool to estimate the required battery size and charging infrastructures. • Bus energy consumption and battery size are sensitive to its transit service type. • City bus Batteries oversized to accommodate small number of trips during the year. [ABSTRACT FROM AUTHOR]

With the announced plans to ban diesel in major European cities from 2025, battery-powered electric buses (BEB) are attracting attention to replace diesel fleets, given their zero tailpipe emissions. However, their large-scale deployment faces several challenges, namely the limited driving range (DR) and the need for adequate charging infrastructure. The limited DR is due to the lower battery specific energy compared to oil-based fuels. Also, the use of electric auxiliaries, especially, air conditioning, reduces the DR further. The DR problem could be resolved either by increasing the battery capacity, which increases the bus cost or by rightsizing the battery alongside an adequate charging strategy to avoid schedule disruption. Therefore, this paper presents a comprehensive energy modeling of a BEB using Dymola, encompassing the different energy systems encountered in BEB. The proposed model serves as a platform to evaluate the bus energy needs during its service to properly size the battery. A powertrain model is presented to emulate the propulsion load. Then, a cabin model alongside a heating ventilating and air conditioning system are developed emulating the thermal load. Finally, auxiliaries necessary for the bus operation are modeled. The energy consumption of each system is assessed under several operating conditions. Image 1 • Study proposes a modeling methodology to assess battery electric buses energy consumption. • Assesses the impact of different driving and weather conditions and passengers load on the energy consumption. • Model serves as a platform to evaluate battery electric buses energy needs to properly size the battery. • Cabin thermal needs and auxiliaries reduce driving range by more than 50% under extreme weather and driving conditions. [ABSTRACT FROM AUTHOR]