A Guide to Creating a Zero Emission Fleet Transition Plan (ZEFTP)

How proper planning for transit bus electrification guarantees successful near term deployments, and flexibility in long term fleet transition.

Anyone operating electric buses on the road will say that transitioning fleets to zero emissions is challenging. It requires more than assessing a new fuel, acquiring funding for infrastructure, training technicians, and following a replacement strategy of the oldest vehicles. They will also say that it’s not impossible, and when past the initial deployment the benefits are recognized and the team is excited to continue the electrification process. In fact, the Federal Transit Administration in recognition of the challenges in fleet electrification requires a ZEFTP with every application for capital funds. 

The MGL team in working with several transit operators in the US and abroad has distilled our experience down to the following steps, suitable for those in the initial phases as well as those far down the road. We consider proper planning as an upfront exercise to guide operators and their engineering firms about ‘what to buy’ and ‘where to deploy’. Every transit fleet has a unique operating environment, and proper analysis and planning will give an edge in winning competitive grant applications 

Set Clear Goals and Objectives 

Establishing clear goals and objectives is critical for the success of your zero-emission fleet transition. Define your objective whether that is to understand the tradeoffs of electric versus hydrogen or to identify when the entire fleet will be replaced with zero emissions technology. Determine who will be on the team to guide decisions in the planning and implementation. Set goals and milestones to keep the project on track – when will the ZEFTP be complete; what portion of the fleet will be transitioned to zero emissions; how much emissions reduction is being targeted; when will procurement begin; and by when will the transition be complete. These goals will serve as guardrails to make all the necessary decisions along the way. 

Assess Your Current Fleet and Operations 

The first step in the planning process is to evaluate the operations of your current fleet. The operating environment of the fleet will have a significant impact on the range expected with electric buses. The operating schedule will dictate when buses can be charged and the type of bus may clarify which portion of the fleet is easier to electrify with current technology capabilities. 

The composition of the fleet, age of vehicles, condition of each, operational constraints, and emissions will identify which vehicles to replace first.  

Identify key operational and maintenance needs associated with a zero-emission fleet, whether battery electric vehicles or fuel-cell electric vehicles. A good understanding of skills and safety requirements will help map to existing workforce programs. 

A fleet as a system approach will identify which routes are easily electrifiable which guides near term deployment plans. This approach also right-sizes the vehicle and charging system, which will save significant capital costs and reduce the time for infrastructure installation. 

Develop a Comprehensive Transition Plan 

A well-designed transition plan is essential for zero emission fleet implementation. A detailed plan addresses key areas including fleet replacement, charging requirements, infrastructure development, total cost of ownership, capital budgets and grant options, workforce training and maintenance.  

Fleets will of course not electrify all at once, and a phase-in plan will guide each stage of procurement, installation, training, and deployment while allowing for learnings and adjustments for the next phase. However it is important to model the entire fleet to inform each phase and thread together the long term transition plan.  

The first step to understanding fleet transition needs is in route energy modeling for the specific operating environment, and the operating schedule to identify times available for charging and fueling the vehicles. Daily energy consumed determines the size of batteries needed and when mapped to operating schedule determines power ratings of chargers. Considering multiple variables simultaneously will clarify which vehicles and which chargers are required for reliable operations and avoid overbuilding and overbuying. A phased plan should align with vehicle replacement schedule and identify power needs. 

Phased-In Fleet Electrification   Fleet Makeup  Peak Power Unmanaged  Peak Power Managed  Transformer Sizes 


7 Transit Blocks, 0 Paratransit ZEVs  450 kW  117 kW  725 kVA vs 225 kVA 
20%   12 Transit Blocks, 0 Paratransit ZEVs  630 kW  233 kW  1000 kVA vs 500 kVA 
25%  8 Transit Blocks, 7 Paratransit ZEV   675 kW  247 kW  1000 kVA vs 500 kVA 
50%   17 Transit Blocks, 13 Paratransit ZEV   1,150 kW  462 kW  2000 kVA vs 750 kVA 
75%  26 Transit Blocks, 20 Paratransit ZEV  1,696 kW  729 kW  2500 kVA vs 1000 kVA 
100%          35 Transit Blocks, 26 paratransit ZEV  1,972 kW  935 kW  3000 kVA vs 1500 kVA 

Table 1: An example of a phased in fleet electrification plan with identified power demand. 

Engage Stakeholders and Partners 

Collaboration with stakeholders and partners is vital throughout the transition process. It is extremely important to engage the local utility right away and often throughout the project. If electrical infrastructure upgrades are required, they could have long lead times and it is beneficial to have utility letter of support when submitting grant applications.  

Illustrating peak power (based on right-sized charging system) and reduced peak with managed charging often changes the considerations when requesting service upgrades from the electric utility. 


Figure 1: An example of a peak load and reduced load with right-sized chargers, and managed charging 

Engage with local communities, elected officials, transit employees, and other relevant parties to evangelize the benefits of electric buses and set expectations about when and where they will be on the road. Their input is necessary to uncover and address concerns, and gather support for the zero-emission fleet transition plan. 

Determine Which Vehicles and Chargers to Procure  

The procurement process for zero-emission vehicles requires careful consideration. Proper planning to accurately size the zero emission vehicle is pertinent to ensure the correct vehicle is chosen for specific operations. Evaluate different vehicle options, such as battery electric buses or hydrogen fuel cell vehicles, based on factors like range, charging infrastructure, and operational requirements. Ensure that the vehicles meet the FTA guidelines and regulatory requirements. Explore opportunities for bulk purchases through state contracts or leasing options. 

Clearly understanding the energy consumed per route under worst case scenarios determines the battery sizes required. Overlying daily energy consumed with the operating schedule identifies the right size of chargers needed to refuel the buses every day. Identifying the largest battery required and the maximum power delivery needed surprisingly overcomes the typical oversizing of vehicles and chargers, and significantly reduces the amount of capital. Knowing what to buy and where to deploy will address many of the questions for fleet operators and set the team up for successful deployments. 



Figure 2: Route energy modeling determines battery sizes and overcomes average efficiency and range. 

Develop Charging/Refueling Infrastructure 

Investing in the necessary charging or refueling infrastructure is important for the successful operation of a zero-emission fleet. Work closely with energy providers, utility companies, and infrastructure developers to plan and implement the upgrades required for your fleet. Consider factors like power capacity, site locations, and access to renewable energy sources. Adhere to safety standards and local regulations throughout the installation process. Seek out partners that can remove risks from your operations and offer financing to cover budget gaps.  

Provide Comprehensive Training 

Transitioning to a zero-emission fleet requires specialized training for your staff. Develop a comprehensive training program that covers maintenance, operation, and safety protocols specific to zero-emission vehicles. Collaborate with vehicle manufacturers, industry experts, and training organizations to ensure your staff receives the necessary knowledge and skills. Ongoing training and support are crucial to maximizing the benefits of the transition.  

Monitor Performance and Adjust as Needed 

Regularly monitor and assess the performance of your zero-emission fleet. Track data related to energy consumption, emissions reductions, and maintenance costs. Analyze the impact on operational efficiency and make necessary adjustments to optimize fleet performance. Evaluate the effectiveness of your transition plan, identify areas for improvement, and implement corrective measures accordingly. 


Transitioning to a zero-emission fleet is an important step toward a more sustainable future. By following the guidelines, transit agencies and organizations can navigate the process successfully. Setting goals, assessing the current fleet and infrastructure, developing a comprehensive transition plan, engaging stakeholders and partners, procuring zero-emission vehicles, developing charging/refueling infrastructure, providing comprehensive training, and monitoring performance are all steps in any alternative fuel transition. 

While the process may seem complex, it’s important to remember that the transition to zero-emission fleets brings numerous benefits. It reduces greenhouse gas emissions, improves air quality, and enhances the overall sustainability of public transportation. It is also generates long-term cost savings through reduced fuel costs and maintenance expenses. 

Enric Sabadell is  a zero emissions transportation analyst with expertise in fleet transition planning, and serves as MGL’s senior manager. 


Read more about transit bus electrification around the world: 

Bus electrification projects underway globally 

Zero emission transit buses in the US  

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Fleet Electrification 101: Modeling & Cost Analysis

September 9, 2021  – All Day Virtual Event

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