Fast-charging station deployment for battery electric bus systems considering electricity demand charges
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This report summarizes results of a battery electric bus (BEB) evaluation at Foothill Transit, located in Southern California. Foothill Transit began a demonstration of three Proterra BEBs in October 2010 to evaluate the battery technology and determine if the BEBs could meet Foothill Transit’s service requirements. Since that pilot project, the agency has added 31 BEBs to its fleet. Foothill Transit is collaborating with the California Air Resources Board (CARB) and the U.S. Department of Energy’s (DOE’s) National Renewable Energy Laboratory (NREL) to evaluate the buses in revenue service. The focus of the evaluation is to compare performance and cost of the BEBs to that of conventional technology in similar service and track progress over time. This report summarizes the results of the BEB and baseline fleets through December 2020.
This report summarizes results of a battery electric bus (BEB) evaluation at Foothill Transit, located in the San Gabriel Valley area of Los Angeles. Foothill Transit is collaborating with the California Air Resources Board and the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) to evaluate the buses in revenue service. The focus of this evaluation is to compare the performance and the operating costs of the BEBs to that of conventional technology buses and to track progress over time. Previous reports documented results from April 2014 through June 2019. This report extends the data analysis through December 2019. The data period focus of this report is July 2019–December 2019. NREL plans to publish progress reports on the Foothill Transit fleet every 6 months through 2020.
Herein we discuss how battery electric buses (BEBs) are rapidly being embraced by public transit agencies because of their environmental and economic benefits. To address the problems of limited driving range and time-consuming charging for BEBs, manufacturers have developed rapid on-route charging technology that utilizes typical layovers at terminals to charge buses in operation using high power. With on-route fast-charging, BEBs are as capable as their diesel counterparts in terms of range and operating time. However, on-route fast-charging makes it more challenging to schedule and manage charging events for a BEB system. First, on-route fast-charging may lead to high electricity power demand charges. Second, it may increase electricity energy charges because of charging that occurs during on-peak hours. Without careful charging scheduling and management, on-route fast-charging may significantly increase fuel costs and reduce the economic attractiveness of BEBs. The present study proposes a network modeling framework to optimize the charging scheduling and management for a fast-charging BEB system, effectively minimizing total charging costs. The charging schedule determines when to charge a BEB, while the charging management strategically controls the actual charging power. Charging costs include both electricity demand charges and energy charges. The charging scheduling and management problem is first formulated as a nonlinear nonconvex program with time-continuous variables. A discretizing method and a linear reformulation technique are then adopted to reformulate the model as a linear program, which can be easily solved using off-the-shelf solvers, even for large-scale problems. Finally, the model is demonstrated with extensive numerical studies based on two real-world bus networks. The results demonstrate that the proposed model can effectively determine the optimal charging scheduling and management for a fast-charging BEB system, which carries the potential for use in large-scale real-world bus networks.
This report summarizes results of a battery electric bus (BEB) evaluation at Foothill Transit, located in the San Gabriel Valley area of Los Angeles. Foothill Transit is collaborating with the California Air Resources Board and the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) to evaluate the buses in revenue service. The focus of this evaluation is to compare the performance and the operating costs of the BEBs to that of conventional technology buses and to track progress over time. Previous reports documented results from April 2014 through December 2016. This report extends the data analysis through December 2017. NREL plans to publish progress reports on the Foothill Transit fleet every six months through 2020.
This report summarizes results of a battery electric bus (BEB) evaluation at Foothill Transit, located in the San Gabriel Valley area of Los Angeles. Foothill Transit is collaborating with the California Air Resources Board and the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) to evaluate the buses in revenue service. The focus of this evaluation is to compare the performance and the operating costs of the BEBs to that of conventional technology buses and to track progress over time. Previous reports documented results from April 2014 through December 2019. This report extends the data analysis through June 2020. The data period focus of this report is January 2020-June 2020. NREL plans to publish progress reports on the Foothill Transit fleet every 6 months through 2020.
This report summarizes results of a battery electric bus (BEB) evaluation at Foothill Transit, located in the San Gabriel Valley area of Los Angeles. Foothill Transit is collaborating with the California Air Resources Board and the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) to evaluate the buses in revenue service. The focus of this evaluation is to compare the performance and the operating costs of the BEBs to that of conventional technology buses and to track progress over time. Previous reports documented results from April 2014 through June 2018. This report extends the data analysis through the end of 2018. The data period focus of this report is July 2018-December 2018. NREL plans to publish progress reports on the Foothill Transit fleet every 6 months through 2020.
This report summarizes results of a battery electric bus (BEB) evaluation at Foothill Transit, located in the San Gabriel Valley area of Los Angeles. Foothill Transit is collaborating with the California Air Resources Board and the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) to evaluate the buses in revenue service. The focus of this evaluation is to compare the performance and the operating costs of the BEBs to that of conventional technology buses and to track progress over time. Previous reports documented results from April 2014 through December 2017. This report extends the data analysis through June 2018. NREL plans to publish progress reports on the Foothill Transit fleet every six months through 2020. performance and the operating costs of the BEBs to that of conventional technology buses and to track progress over time. Previous reports documented results from April 2014 through December 2017. This report extends the data analysis through June 2018. NREL plans to publish progress reports on the Foothill Transit fleet every six months through 2020.
This report summarizes results of a battery electric bus (BEB) evaluation at Foothill Transit, located in the San Gabriel Valley area of Los Angeles. Foothill Transit is collaborating with the California Air Resources Board and the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) to evaluate the buses in revenue service. The focus of this evaluation is to compare the performance and the operating costs of the BEBs to that of conventional technology buses and to track progress over time. Previous reports documented results from April 2014 through December 2018. This report extends the data analysis through June 2019. The data period focus of this report is January 2019-June 2019. NREL plans to publish progress reports on the Foothill Transit fleet every 6 months through 2020.
We report studies on the electric bus system planning problem have typically focused exclusively on either the deployment of charging infrastructure or the scheduling of charging events; few have examined the impact of charging facility deployment on charging activities. Considering the interdependence of system design and operational strategies, this study proposes a two-phase optimization framework for charging infrastructure planning and charging scheduling for battery electric bus systems. An integrated optimization model is first developed to simultaneously optimize charger deployment, on-board battery capacity, and charging schedules. A charging scheduling model is further proposed and a rolling horizon approach is utilized in the second phase to optimize the real-time charging scheduling of electric buses. Compared to existing electric bus system planning methods, the proposed integrated model can reduce the total system cost by 19.5%. In addition, compared to uncontrolled charging, the proposed rolling horizon-based charging strategy can reduce the total charging cost by 68.3%.
Battery-electric buses (BEBs) are a promising technology for replacing diesel buses and reducing their environmental burden. However, their charging process can take several hours, depending on the charging technique and strategy, making them susceptible to schedule disruptions. Furthermore, the selection of the charging strategy and battery size can increase the total capital investment and operational expenses of a BEB fleet, which is a major obstacle to its adoption. Therefore, to minimize the total cost of ownership (TCO) and prevent schedule disruptions, it is essential to establish a well-defined approach to determine an appropriate battery size and charging strategy for BEB fleets. This paper presents a method for reducing the TCO of BEB by determining the optimal battery size and charging strategy for each bus while satisfying operating constraints. The method involves a two-step optimization algorithm that uses Dynamic Programming and Genetic Algorithm. Further, the study applies this approach to the bus fleet serving line 21 in Paris and generates the optimal battery sizing, charging strategy, and required charging infrastructure. The results indicate that 100 kWh batteries offer the best trade-off between capital and operational expenditure for the fleet deployment if used with 65–85 kW chargers at bus terminals.
Beginning in March 2017, Long Beach Transit began operating a fleet of 10 battery electric buses (BEBs) in its service area in Southern California. These electric buses, produced by BYD, are 40-foot buses that are typically charged overnight. Long Beach Transit is collaborating with the California Air Resources Board (CARB) and the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) to evaluate the buses in revenue service. NREL evaluated the first year of Long Beach Transit’s BEB fleet under Federal Transit Administration funding and published a report covering results from January 2018 through December 2018. CARB provided funding to cover a second year of evaluation. This report provides an update to the previous reports and is focused on the second year of operation from January 2019 through December 2019. Data are provided on a selection of compressed natural gas (CNG) buses as a baseline comparison.
Electrifying the transportation sector holds many promises and there are numerous strategies for doing so, including the deployment of battery electric buses (BEBs). BEBs can improve air quality (particularly in urban areas), may help curb greenhouse gas emissions, and can have positive impacts on public health and the quality of life for city inhabitants. This fact sheet steps through the six essential BEB considerations: 1) implementation planning, 2) technology selection, 3) economic impacts, 4) charging infrastructure, 5) operational, and 6) maintenance.
Duluth Transit Authority (DTA) collaborated with the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) to evaluate a fleet of seven battery-electric buses (BEBs) in revenue service in Duluth, Minnesota. The focus of the evaluation was to compare performance and cost of the BEBs to that of conventional technology buses in similar service and track progress over time. DTA enlisted the help of the Center for Transportation and the Environment (CTE) to manage the project and provide technical services with the BEB fleet and infrastructure. This report summarizes the results of the BEB evaluation and contains a combination of analyses performed by NREL and by CTE during the overall data collection period of December 2018 through February 2022.
The National Renewable Energy Laboratory (NREL) in partnership with USAID Mexico's Low Emissions Development (MLED) II program explored the technical feasibility of transit bus electrification in Mexico City (CDMX) and León. NREL and USAID engaged CDMX and León transit agencies to understand routes of interest and existing fleet fueling and bus specifications.
The U.S. Federal Transit Administration (FTA) funds a variety of research projects that support the commercialization of zero-emission bus technology. To evaluate projects funded through these programs, FTA has enlisted the help of the National Renewable Energy Laboratory (NREL) to conduct third-party evaluations of the technologies deployed under the FTA programs. NREL works with the selected agencies to evaluate the performance of the zero-emission buses compared to baseline conventional buses in similar service. The evaluation effort will advance the knowledge base of zero-emission technologies in transit bus applications and provide 'lessons learned' to aid other fleets in incrementally introducing next generation zero-emission buses into their operations. This report provides preliminary performance evaluation results from a demonstration of four all-electric trolley-replica buses and two electric vehicle charging stations at County Connection in the San Francisco Bay Area. NREL developed this preliminary results report to quickly disseminate evaluation results to stakeholders. Detailed evaluation results will be published in future reports.