Meeting the charging needs of electric bus fleets


According to the US Energy Information Administration (EIA), transportation is the most fossil fuel dependent of all sectors and accounts for up to 37% of US CO2 emissions. Shifting to more sustainable forms of transport is essential to the success of efforts to combat climate change. Part of the transport market is particularly ripe for the transition to battery-powered vehicles – mass transit systems, especially bus fleets.

Many transit agencies are already actively engaged in efforts to convert fleets to electric vehicles, driven in part by government mandates and incentives. The recent Inflation Reduction Act enacted on August 16, 2022 will likely contribute to this momentum.

This transition will be a complex undertaking for the approximately 6,800 transit organizations and authorities in the United States, one that will require substantial upgrades and modifications to the nation’s power grids. The transition to electric vehicles will also require new charging infrastructure, digital platforms to better manage fleet charging needs, and targeted upgrades to regional power grids to meet the associated increase in demand for electricity. ‘electricity.

The transition to electric vehicles presents opportunities and challenges

Switching public buses to electric vehicles can have an outsized impact on reducing CO2 emissions, given their relatively high fuel consumption (due to high usage) and high exhaust gas production, which has a negative impact on urban air quality. Transit agencies can significantly reduce, if not eliminate, the use of fossil fuels by introducing electric buses into their fleets, reducing air pollution and lowering their carbon footprint.

The transition to electric fleets requires much more than simply replacing internal combustion vehicles with battery-powered alternatives. Larger bus depots would very quickly become large consumers of electricity, down to the megawatt level, as transit agencies install charging infrastructure to support their growing electric vehicle fleets. Many bus stations are in commercial or industrial areas, where they may compete with other large energy consumers for electricity, which could hinder their adoption of electric vehicles.

Transit agencies will also need to consider their long-term charging needs when planning the installation of electric vehicle charging infrastructure. Many bus stations have little space available, and certainly not enough space for individual loads, 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 smart public transport electric vehicle charging, called Grid-eMotion™ Fleet.

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

Grid-eMotion Fleet is designed to provide grid connection flexibility and ensure compliance with the most stringent power quality requirements. The chargers are available from 50 to 600 kW, combined in cabinets for easy maintenance and operation. The charging stations are designed to ensure full interoperability with current and future electric vehicle fleets charged with direct current via a socket or pantograph.

This charging infrastructure for large fleets enables efficient operation in confined spaces. The system can be deployed in smaller-scale configurations for early-stage fleet conversions, then scaled as EV fleets grow, eventually supporting dozens or hundreds of vehicles depending on needs to meet the requirements of small regional transport authorities to fleet operators serving large metros.

The advantages of this approach include:

  • Reduced space and wiring
  • Simplified interfaces
  • Lower Harmonic Distortion
  • Lighter installation on car parks
  • Improved reliability, availability and maintainability
  • Fewer activities on site, shorter delivery times and reduced risk of project delays
  • Containerized, fully assembled, tested, ready to install
  • Integrated with SCADA, energy management system (Open Charge Point Protocol – OCPP)
  • Battery energy storage systems or integration of photovoltaic/solar power plants
  • Connection to the existing DC network for customers already operating tram, metro or streetcar networks

Success factors for the EV transition

To ensure the successful introduction of electric vehicles at scale, infrastructure decisions are best made early in the fleet transition process. Transit agencies should consider the endgame of their deployment strategy, identifying requirements such as the number of charging slots needed, total expected energy consumption, peak charging demand and more. They also need to determine how best to begin this transition – which buses to convert to electric vehicles based on the route, energy requirements (for vehicle batteries and charging infrastructure, available downtime along routing and more.Failing to take these factors into consideration early can lead to the development of a sub-optimal system that can ultimately disrupt schedules and daily operations, cost millions in subsequent system modifications or replacements, and ultimately delaying fleet deployment by months or even years, adding both cost and complexity to their plans.

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

Equally important, local utilities may need to upgrade their distribution networks with additional feeder line and circuit capacity to meet increased demand. These types of upgrades can take months or even years, so transit agencies should ensure that utilities incorporate their requirements into their integrated resource and capital plans. These conversations need to happen now.

Finally, transportation agencies will almost certainly transition their fleets over time in accordance with their existing vehicle retirement and replacement schedules. Electric vehicle charging infrastructure will need to operate in parallel with traditional gas or diesel refueling systems and be integrated with a range of existing systems used to support routing and dispatching, maintenance scheduling and other business processes. These systems will also need to be complemented by EV-specific fleet management solutions, which will be needed to track things like vehicle energy consumption, each vehicle’s state of charge, battery life battery, optimized planning for maximum vehicle availability, route and traffic simulations, and more.

Change planning

The transition to the use of electric buses is a crucial step in the transition to more sustainable transport. To ensure the success of this endeavor, transit agency plans must take into account the necessary network modernization, large-scale deployment of electric vehicle charging infrastructure and alignment of a myriad of operational processes. In this way, they can help ensure a more sustainable future for our transit systems.


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

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