Addressing the charging needs of EV bus fleets

Sept. 9, 2022

According to the U.S. Energy Information Administration (EIA) transport has the highest reliance on fossil fuels of any sector and accounts for up to 37% of CO2 emissions in the U.S. The shift toward more sustainable forms of transportation is critical to the success of efforts to combat climate change. One part of the transportation market is especially ripe for the transition to battery-powered vehicles - public transit systems, specifically bus fleets.

Many public transit agencies are already actively engaged in efforts to convert fleets to EVs, partly driven by government mandates and incentives. The recent Inflation Reduction Act passed into law on August 16, 2022, will likely add to this momentum.

This transition will be a complex undertaking for the estimated 6,800 public transit organizations and authorities in the U.S., one that will require substantial upgrades and modifications to the country’s electrical grids. The EV transition will also require new charging infrastructure, digital platforms to better manage fleet charging needs, and targeted upgrades to regional power grids to serve the associated increase in electricity demand.

EV Transition Presents Opportunities and Challenges

Shifting public buses to EVs can have an outsized impact on the reduction of CO2 emissions, given their relatively high fuel consumption (due to their high utilization) and their significant production of exhaust, which negatively impacts urban air quality. Public transit agencies can dramatically reduce or even eliminate the use of fossil fuels by introducing EV buses to their fleets, cutting air pollution and reducing their carbon footprint in the process.

The transition to electric fleets requires much more than simply replacing internal combustion vehicles with battery-powered alternatives. Larger bus depots would become major consumers of electricity, up to the megawatt-level, very quickly, as transit agencies install charging infrastructure to support their growing EV fleets. Many bus terminals are in commercial or industrial zones, where they may be competing with other large-scale energy consumers for electricity, which could hamper their adoption of EVs.

Transit agencies will also need to consider their long-term charging needs when planning the installation of EV charging infrastructure. Many bus terminals have little room to spare, and certainly not sufficient space for individual charges, such as those increasingly available at grocery stores and highway service areas. Fortunately, large-scale, fast-charging infrastructure is available, and can be optimized to support most real estate configurations.

Large-scale Fleet Charging Infrastructure

Hitachi Energy offers fleet operators a scalable, modular, and fully customizable solution for large-scale EV charging of smart public transport, called Grid-eMotion™ Fleet.

By implementing AC/DC rectification at a central location, Hitachi Energy’s pioneering fleet charging technology can reduce the demand for space by up 60% in depots and optimizes energy consumption from the grid through an integrated digital ecosystem.

Grid-eMotion Fleet is designed to offer flexibility of connection to the utility grid and ensure compliance with the most stringent power quality requirements. Chargers are available from 50 to 600kW power, combined in cabinets to facilitate easy maintenance and operation. Charging points are designed to ensure full interoperability with current and future EV fleets charged in DC via plug or pantograph.

This charging infrastructure for large fleets provides efficient operation in confined spaces. The system can be deployed in smaller-scale configurations for early-phase fleet conversions, and then scaled up as EV fleets grow, ultimately supporting dozens or hundreds of vehicles as needed to meet the requirements of smaller, regional transit authorities up to fleet operators serving large metros.

Benefits of this approach include:  

  • Reduced space requirements and cabling
  • Simplified interfaces
  • Lower harmonic distortion
  • Lighter installation at parking places
  • Improved reliability, availability, and maintainability
  • Less site activities, shorter delivery time and lower risk of project delay
  • Containerized, fully assembled, tested, ready to install
  • Integrated with SCADA, energy management system (Open Charge Point Protocol - OCPP)
  • Battery energy storage systems or photovoltaic/solar plant integration
  • Connection to existing DC grid for customers already operating tram, metro, or trolley networks

Success factors for the EV Transition

To ensure the successful introduction of EVs at scale, infrastructure decisions are best made at the beginning of the fleet transition process. Transit agencies should consider the end game of their deployment strategy, identifying requirements such as the number of charging slots needed, total anticipated energy consumption, peak charging demand and more. They alao need to determine how best to begin this transition – which buses to convert to EVs base on route, energy requirements (for both vehicle batteries and charging infrastructure, available dwell time along the route and more. Failing to take these factors into consideration early on can result in the development of a sub-optimal system that can ultimately disrupt daily schedules and operations, cost millions in subsequent modification or replacement of systems, and ultimately delay fleet rollouts by months or even years, adding both cost and complexity to their projects.

For instance, even with the most flexible charging infrastructure, depots may need to be modified or restructured to accommodate the new equipment. Maintenance facilities will need to be upgraded to support EV charging, while maintaining both gas and diesel fueling systems simultaneously, in some cases for more than a decade, depending on the vehicle depreciation schedule.

As important, local utilities may need to upgrade their distribution grids with additional feeder line and circuit capacity to support the increased demand. These kinds of upgrades can take many months or even years to complete, so transit agencies need to make sure that utilities have their requirements built into their integrated resource and capital plans. Those conversations need to be happening now.

Finally, transit agencies will almost certainly transition their fleets over time, aligned with their exiting vehicle retirement and replacement schedules. EV charging infrastructure will need to operate in parallel with traditional gas or diesel fueling systems and be integrated with a range of existing systems used to support routing and dispatch, maintenance scheduling, and other operational processes. These systems will need to be supplemented with EV-specific fleet management solutions as well, which will be needed to track things like vehicle energy consumption, each vehicle’s state of charge, battery life, optimized scheduling for maximum vehicle availability, route and traffic simulations, and more.  

Planning for Change

Transitioning to the use of EV buses is a critical step in the shift toward more sustainable transportation. To ensure the success of this endeavor, public transit agencies’ plans need to account for the needed grid modernization, large-scale EV charging infrastructure deployment, and alignment of a myriad of operational processes. In this way, they can help enable a more sustainable future for our public transit systems.

Alexandre Lalonde
Business Development Manager
EV Charging Solutions - North America
[email protected]
+1 514-757-6330