or hydrogen technology in order to avoid the entire fleet being affected if one of the technologies experiences setbacks within the market.

Maintaining power and hydrogen fuel on site is also a concern, and many of the adaptation measures the transit agency has implemented are to mitigate risks associated with loss of power or hydrogen fuel shortages.

Responsibilities During an Event

The COVID-19 pandemic provided AC Transit with key information and guidelines to follow for how it should operate its service during emergencies. AC Transit learned that the number of resources needed to meet 70–80% service requirements during emergencies is unrealistic for agencies to achieve, and during the pandemic, the agency determined that it was only necessary to run 65% of its fleet. This is what was needed to deliver passengers, most of whom were essential workers, to their destinations during the emergency. AC Transit has determined that this service level will be applicable in most emergencies and is an appropriate use case for planning efforts.

Agency staff also demonstrated their capabilities as a team during emergencies. During the pandemic, emergency response staff attended regularly scheduled virtual calls to strategize operations, take the appropriate measures, and ensure the adjusted service requirements continued to be met. AC Transit advises that all transit agencies have staff dedicated to emergency response and support planning, as this proved to be essential during the time of the pandemic.

Although the agency already had emergency operations in place, the pandemic provided the real-world experience, which allowed staff to focus on a realistic scenario for evaluating how the agency would have responded if a high percentage of its bus fleet were ZE. AC Transit staff began to think about specific answers to questions related to advancing its emergency response operations for the agencyʼs current and future ZEB fleet. These included the following:

• What technology is going to be on site if the agency achieves 100% ZE?
• How will a ZE fleet be integrated into a plan that currently exists?
• How many days can the agency operate its fleet on regular service with hydrogen and battery-electric buses?
• If the power grid is down and the chargers cannot provide energy to the buses on site, what measures should be taken?
• How should the agency strategize charging if it is only focusing on powering the buses that are required to operate during emergencies (65% of the fleet)?
• Based on the state of the environment/emergency, what is the agencyʼs specific role? Providing service? Providing shelter? Traveling out of normal service sites if other transit service jurisdictions need assistance?

In addition, AC Transit is obligated to respond to California state recommendations for emergency response planning. The state encouraged transit agencies to review various emergency response plans. AC Transit has looked into small- and large-scale plans for various emergencies, including floods, fires, earthquakes, and terrorist attacks. The agency has maintained a good relationship with first responders in its area; law enforcement personnel have traveled on site to run various drills on the buses.

AC Transit is proactive when it comes to emergencies; many times, agency staff have taken initiative to serve the community during emergencies, such as power outages, rather than waiting until normal operations are back up and running. AC Transit understands the importance of providing emergency response support, which is why staff are taking the necessary measures to ensure the agencyʼs ZEB fleet is able to stay in service.

Implementation of Resilience Measures

AC Transit has implemented and is planning to implement a number of adaptation measures to increase the resilience of its ZEB fleet.

Linear Generator

AC Transit is in the early stages of implementing a linear generator to provide backup power. AC Transit will have total control of the type of fuel that will be used for the generator. It can be powered by natural gas or by hydrogen, providing flexibility based on feedstock availability during an emergency. When considering sizing backup power, AC Transit determined that it was not necessary to be able to power the entire fleet, as full service levels will not need to be met during an emergency. AC Transit will need to be able to power 20% of its BEB fleet at each of its divisions.

Data Integration and Quality, Software, and Technology Protection

AC Transit had experienced issues with firmware updates being applied to chargers or buses that resulted in the buses being unable to charge. To avoid this situation, AC Transit developed a board policy for data integration and quality that states its information technology (IT) department has to approve updates before they are made. This policy has been pulled into project contracts; any contractor the agency works with now has to abide by this policy.

Cybersecurity

AC Transit recognized the need for a dedicated cybersecurity practice to protect its growing ZEB fleet, which is heavily reliant on telematics and network connectivity. Previously managed informally by the IT department, cybersecurity efforts left key vulnerabilities unaddressed. To address these gaps, AC Transit, led by dedicated cybersecurity leadership, established a comprehensive framework to protect its systems and ensure redundancy.

AC Transit is actively developing a comprehensive governance, risk, and compliance (GRC) platform that ensures all vendors and third-party contractors comply with stringent cybersecurity policies. GRC protocols are essential in safeguarding the ZEB fleet by ensuring adherence to both internal and federal cybersecurity standards, including the Center for Internet Security (CIS) (equivalent to National Institute of Standards and Technology 800-53) Cybersecurity Framework and Presidential Executive Orders related to critical infrastructure and supply chain security.

To address the evolving cyber threats facing its IT infrastructure, AC Transit has implemented a Zero Trust security model. This is especially important given the reliance on connected devices for fleet operations, charging infrastructure, and telematics. Zero Trust ensures that all access points, both internal and external, are authenticated and verified. Multi-factor authentication is mandated across all systems, protecting access to network control points and telematics systems.

In alignment with Presidential Executive Order 14028, which focuses on enhancing cybersecurity for critical infrastructure, AC Transit has integrated supply chain risk management into its operations. The executive order emphasizes securing the software supply chain and enforcing vendor compliance with strict cybersecurity standards. AC Transitʼs procurement and contract teams collaborate with the GRC and cybersecurity platforms to ensure that all hardware and software vendors, particularly those involved in ZE technology, comply with federal mandates. Regular audits and third-party penetration tests further strengthen supply chain resilience.

AC Transit is currently finalizing its artificial intelligence (AI) policy, and subsequent AI security controls are being developed. AI-based technologies provide significant operational advantages, such as enhancing route optimization and charge management, but they also pose distinct cybersecurity risks. These AI systems process large datasets and are potentially

susceptible to manipulation. In response, AC Transit has implemented stringent data validation protocols and regularly reviews AI decision-making processes to ensure these systems are comprehensively integrated within the Zero Trust framework. Additionally, sophisticated monitoring tools are utilized to identify any anomalies that might indicate cyberattacks or errors in AI training models, further securing the technology.

Given that the ZEB fleet depends on a robust electric vehicle (EV) charging infrastructure, securing these systems from cyber threats is critical. AC Transit has implemented security controls across hardware (charging stations), network (telemetry and communication), and software (management platforms). These controls adhere to recognized standards such as CIS/NIST, with regular penetration testing, vulnerability assessments, and continuous monitoring to safeguard EV infrastructure.

Hydrogen Fuel

AC Transit is planning to have four hydrogen facilities with 24/7 operation, so partnering with reliable fuel suppliers with multiple sources of supply is important. To ensure this, AC Transit is working to develop language in its project contracts that requires the fuel provider to have the ability to purchase fuel from other companies or determine an alternate way for sourcing fuel for AC Transit if its supply is low.

Diesel Reserve/Contingency Fleet

AC Transit has an ICE contingency fleet and considers it to be a very reliable choice for ZEB fleet resiliency.

Funding

In AC Transitʼs committee focused on ZE fleet operations, agency staff constantly discuss what funding is available and what projects the funding can support in order to continue to advance staff knowledge, the ZEB transition, and on-site operations. This forum streamlines the ability for staff to determine what projects are needed and identify funding opportunities to meet agency needs.

Key Takeaways

AC Transitʼs long history of successfully running ZEBs has resulted in an agency with clear systems in place to integrate ZEBs into the fleet holistically, including from a resilience perspective. Staffing structures, communication, and continuous education have been critical to AC Transitʼs ongoing success and resilience planning efforts.

Antelope Valley Transit Authority

Zero-Emission Fleet Status

AVTA of California has had a fully BEB fleet since the beginning of March 2022, 18 years before the 2040 goal of the California Air Resources Boardʼs Innovative Clean Transit Regulation. AVTA achieved a fully ZEB fleet faster than originally anticipated, but the agency has been able to make the necessary operational adjustments to successfully run its BEBs and provide transit service for the community.

AVTA received its first BEB, a pilot bus from BYD, in 2014, which the agency still has in service today. AVTA recently received 26 new BYD BEBs, which brought the total fleet size to 102. AVTA no longer has any diesel buses on site and achieved the complete conversion of its fleet to ZE in 7 years from the deployment of the first BEB to the retirement of the last diesel bus.

Resilience Planning Approach

Resilience has always been part of AVTAʼs planning efforts. In 2017, AVTA installed a 1.5 megawatt (MW) generator on site to provide backup power. The agency is currently planning to install an additional generator on site during the construction of AVTAʼs solar project.

Additionally, because AVTA is a leader in the transition to ZEBs, the agency makes efforts to provide support to other neighboring entities working to transition to ZEBs as well. AVTA has partnered with a nearby school system that is transitioning to BEB and will be sharing its chargers in an effort to increase the resilience of the larger community.

Key Concerns

Since AVTA only operates BEBs, ensuring the agency and buses have what they need to run successfully is important. This includes access to new parts, technical support, and early communication with vendors. AVTA has not had any issues communicating and working with vendors, but sourcing equipment like switchgear has been a challenge for the agency.

AVTA is also concerned about the constantly evolving nature of new technology, which can make it challenging for agency staff to maintain buses and chargers, especially if existing buses and supporting infrastructure on site have older technologies that do not reflect the most recent equipment in the market and may have fewer options for support. A related concern is that staff members will retire without passing down their BEB knowledge to newer staff members.

In addition, in order for AVTA to provide successful service to the community, it is important to ensure that on-route charging is working as efficiently as possible with minimum downtime.

Responsibilities During an Event

AVTA has a standard operating procedure (SOP) that it follows in the event of emergencies.

AVTA is limited in the services it is able to provide during emergencies, such as blackouts, in comparison to when it operated diesel buses. AVTA has engaged with community partners regarding the range capabilities of its fleet, and no major concerns have been expressed with the range constraints of the vehicle. The agency has specific measures in place to ensure its modified service requirements are met during emergencies.

Implementation of Resilience Measures

AVTA has implemented a number of resilience measures, including high-capacity inductive charging, solar, and a 1 MW generator.

Bus Range Monitoring and High-Capacity Inductive Charging

At the beginning of AVTAʼs fleet transition to ZEB, the agency worked with Wave to pilot high inductive chargers with a 50-kW system. AVTA has since upgraded this system to 225 kW. There are many safety features included in the high-capacity inductive chargers. When the charger was first installed, Wave provided AVTA with one to two on-site technicians each week, Monday through Friday from 8am to 9pm. This provided AVTA staff with significant learning opportunities on how to successfully operate the system.

With Wave inductive charging, the BEBs are able to stay in service all day. Charging is structured in a software program called Optibus. This program identifies the bus SOC, bus location, and when the bus should be charging. The system is set up so that buses charge during the day in 10-minute increments, which provides AVTA with approximately 12–15 miles of range. Optibus also evaluates bus data and suggests which buses should operate on which routes. Although AVTA has a large service area, Optibus has allowed the agency to meet its range requirements.

In turn, AVTA has not had to significantly increase its original fleet size. At the start of AVTAʼs transition to BEB, the agency was replacing each diesel bus with two BEBs, but with the higher power Wave chargers installed, AVTA has been able to start transitioning to BEBs with one-for-one bus replacement. AVTA has a total of 15 Wave induction primaries, with one of them being in the yard. On-route chargers may also act as redundant infrastructure for depot chargers in the event that a localized power outage or charger issue prevents buses from charging at the depot without impacting the on-route chargers.

Backup Generator

AVTA currently has a 1.5 gigawatt on-site backup generator to improve resilience in the event of a power outage. This generator can charge 15 buses simultaneously in the event of an emergency. AVTA has used this generator two times, including one time when the power went out for about 5 hours.

On-Site Technicians/Close Proximity to Vendors

• Close Proximity to Vendors: AVTA also considers being in close proximity to its BEB and infrastructure vendors to be a form of resilience. BYD is four blocks down the street from AVTA, and this has made it very easy for AVTA to get on-site assistance if there is an issue with the buses and/or chargers.
• Software Sustainability: Most of AVTAʼs BEBs are compatible with software updates, with the exception of two BEBs that are 2014 models. The agency has on-site technicians from the vendors who perform maintenance on the buses and chargers, which includes installing program updates when needed. The technicians inform AVTA staff when an update will occur and what it will consist of, as well as how the update affects bus and charger operations.
• Communication with Vendors: AVTA has both BYD and MCI on call when the agency needs assistance. This has been helpful for ensuring a smooth transition and meeting service requirements.
• Agency Technicians: AVTA staff are also trained; staff can work up to a level 3 fault on chargers. Charger vendors have to come on site to assist with level 4 or higher charger faults.

Bus Fires

AVTA has a set procedure to follow if a thermal event occurs. During an event, AVTA will remove the buses out of the bay and yard to prevent the fire from spreading. AVTA works with contractors that are responsible for coming on site to do this, which should be effective in preventing and/or mitigating damage from occurring. Contractors are expected to be on site with their preparedness plans and tools needed to provide as much safety assistance and expertise as possible during an event.

In addition, all of AVTAʼs BEBs have fire detection systems. MCI has developed an early warning system that will send information to staff via text message, alerting them if a thermal event or high-voltage fault is likely to occur. This detection system will allow AVTA to know which staff members, if any, should be on site and what needs attention. MCI and BYD both provide the option to implement early fire detection systems on buses.

These measures serve to mitigate the risk and reduce the consequences associated with a bus fire.

Solar and Battery Storage

AVTA is currently working on installing a 2.6 million kW/year solar battery storage system. When installed, any loss of power will allow for the storage to kick in and provide backup energy and distribute power as needed. Power provided by solar in the event of an emergency will be

able to be sustained for 1–2 days, depending on sun conditions. This installation should be complete within the next 48 months.

Funding

AVTA has received funding from the California State Transportation Agency (CalSTA)ʼs Transit and Intercity Rail Capital Program 6 years in a row, which has been crucial for successfully operating its BEB fleet and implementing supporting resilience and redundancy measures to best operate and maintain its fully BEB fleet.

Key Takeaways

As one of the first agencies in the United States to reach a fully ZEB transit fleet, AVTA is a model for what late-stage resilience implementation looks like. The agency has already implemented several resilience measures to ensure that it is able to meet service requirements despite the range limitation and power outage vulnerability of a 100% BEB fleet. It is also in the process of implementing a new solar energy system with a battery energy storage option to improve its ability to provide service in the event of a power outage, while also lowering its fuel costs. This demonstrates that a resilience plan may not need to be 100% implemented before achieving a fully ZEB fleet.

Metro Transit (MN)

Zero-Emission Fleet Status

Metro Transit has a fleet of 762 buses, and 8 of them are battery electric. The agency first introduced BEBs to its fleet in 2019.

Resilience Planning Approach

Metro Transit is currently relying on its contingency ICE fleet and redundant power feeders to provide the most resilience. As of now, Metro Transit has not planned for other backup sources of energy, such as diesel generators.

Key Concerns

Metro Transitʼs primary ZEB fleet resilience concerns are related to power and charger reliability, bus reliability, and mitigating the impacts of cold weather on operations.

Responsibilities During an Event/Consequences

Metro Transit provides emergency services. Buses have served as mobile vaccine clinics, and they often serve as warming shelters. There is uncertainty around how to manage providing these kinds of services with a ZEB fleet.

Metro Transit has not conducted any studies on mutual aid requirements or service continuity in the event of a serious grid event yet. The agency anticipates having a study regarding these topics included in its 2028 transition plan update. At this time, Metro Transit has not assessed what its minimum service requirements would be in the event of an emergency with a ZEB fleet, but understands that this will be important to define resilience requirements.

Metro Transit is a part of a statewide emergency response hierarchy, and transit is a sector of this, so although Metro Transitʼs role has not been studied with a ZEB fleet yet, it is likely that the agency would be required to play a role.

Adaptation Measures Evaluated

Metro Transit has explored a number of adaptation measures focused on ZEB fleet resilience.

Charge Management

Metro Transit has identified its need for a charge management system in the future that centralizes all vehicle and charger telematics to improve efficiency and operations. Having this data on a single platform would be beneficial to the team. Metro Transit plans to start incorporating this resilience measure over the next several years.

Electrical Infrastructure Design

Metro Transit has worked very closely with Xcel Energy, its local power utility, to design its electrical infrastructure. This has provided Xcel and Metro Transit with critical information on long-term planning as Metro Transit increases the portion of its fleet that is ZE. This planning effort could result in a reduced number of capital projects to undertake, as equipment can be sized for the growing load, rather than on a per-deployment basis. Metro Transit is building out infrastructure based on the largest power feeder size Xcel Energy can provide (2.5 MW). For example, if the agency needs a minimum of 600 kW for its next buildout, it will still install 2.5 MW of available power. The agency anticipates needing multiple feeders at each depot in the future.

One recommendation from the utility area engineer was to install dual feeds. It is similar to how the electrical infrastructure for critical loads like hospitals is designed. The utility would bring in two separate feeders from different circuits, and each one would be capable of carrying the full load of the facility in a brownout. If one feeder were offline, the other could power the entire facility. There would be an automatic switchover capability, so if one feeder was offline, the other would automatically provide electricity for the full facility. If both feeders were offline, there would be a power outage at the facility.

Xcel Energy has also recommended that Metro Transit install primary service when constructing a new bus operations and maintenance facility. While primary service requires more upfront capital from Metro Transit than secondary service does, in the event of an emergency, primary service lines tend to come back online before secondary service lines do. Secondary service is typically used at retrofits of existing bus operations and maintenance facilities, as the existing service is typically secondary service, and for safety reasons, the power utility does not mix service types at one address.

Implementation of Resilience Measures

Metro Transit has implemented a few resilience measures, with on-site dual utility feeders being the most developed.

Charging

Each bus has access to two different dispensers for charging from each parking spot. This means that if a dispenser stops working, then a bus can easily be connected to a different dispenser or charger without having to be moved within the garage. To ensure charging needs are met as an agency still early in its transition to ZEB, Metro Transit currently has one charger per bus but plans to have one charger per every two buses as the transition furthers. The impact of one charger being offline is greater with a smaller fleet size, so as Metro Transitʼs BEB fleet grows, this will not be as significant, and it is anticipated that one charger per bus will not be necessary.

Dual Utility Feeds

Metro Transit has installed these at a new facility. It has two feeders carrying 4 MW of load in standard operation with an automatic throwover switch. In an emergency situation, each

feeder can carry 8 MW of load. A similar model is under construction at a second facility with two feeders carrying 2.5 MW of load in standard operation with an automatic throwover switch.

Indoor Bus and Infrastructure Housing

Metro Transit fuels, washes, maintains, and stores all of its buses indoors, which is an important resilience measure for any propulsion type bus. One ZEB-specific benefit is that this prevents the agency from experiencing cold-weather pre-conditioning challenges, such as using battery energy for warming up the bus at the start of the day. The buses also have diesel heaters installed to increase range on winter days. This is not an adaptation measure that is new to the agency, as the agency has diesel heaters on its ICEBs, too. Metro Transit designs its service such that the BEBs may only be deployed on blocks where the BEB can complete the service under challenging winter conditions.

These measures ensure that cold weather will not prevent the buses from being able to meet service requirements.

Contingency ICE Fleet

Metro Transit has a backup contingency ICE fleet on site. If a BEB is not available for revenue service, a diesel bus is substituted.

Key Takeaways

Coordinating with the local utility (Xcel Energy) has been critical for Metro Transitʼs resilience planning efforts.

Montgomery County

Zero-Emission Fleet Status

MCDOT of Maryland currently has 377 buses in its fleet, with 4% of the buses being battery electric. Its first BEBs were put into service in 2020. Montgomery County currently has 14 BEBs in service, 13 fuel cell electric, and 73 BEBs in procurement, which will increase the agencyʼs ZEB fleet to 20%. Montgomery County competitively selected GILLIG for a partnership to deploy 100 ZEBs over the next 3 years. The agency plans to order the remaining 27 bus options in 2025 for an anticipated delivery in 2027.

Montgomery County is required to achieve a 100% fully ZEB fleet by 2035, and it is on track to meet this objective by 2033, provided adequate funding is available. Current plans show that fuel cell electric buses will be the predominant propulsion type in this fleet.

Resilience Planning Approach

Resilience has been part of the ZEB planning effort at Montgomery County from the start. Resilience is a key component of any capital project Montgomery County undertakes, and the agency relied on existing processes as the foundation for resilience planning for its ZEB fleet. Montgomery County has an understanding of the key threats experienced in its area and the required service levels the agency must provide in the event any of those threats occur. Through the agencyʼs resilience planning process, Montgomery County decided to install a microgrid at its Brookeville facility.

Key Concerns

There were a few key concerns that resulted in Montgomery County planning to build out a microgrid solution to support its BEB fleet. One was resilience and being able to charge buses

to provide service in the event of an extended power outage. Another was the timing of utility power upgrades. The uncertainty of electrical utility pricing was also a concern.

Threats

Environmental threats local to Montgomery County include, but are not limited to, hurricanes and storms, earthquakes, and any other sabotage to the power lines. A power outage resulting from these types of events was the main threat that the microgrid solution was implemented to mitigate.

Responsibilities During an Event/Consequences

Montgomery County expressed that during an emergency event, it is likely that it will have to run anywhere between 70 and 100 buses for its emergency service operations. Montgomery County focused its resilience planning for its ZEB fleet around this requirement.

Adaptation Measures Evaluated

Montgomery County has looked at a few different adaptation measures to mitigate the risks associated with threats to service resulting from extended power outages. A basic adaptation measure, which is particularly effective when ZEBs are a small percentage of the fleet, is an internal combustion engine (ICE) contingency fleet. Other measures evaluated include incorporating hydrogen fuel cell electric buses into its ZEB fleet plans and installing microgrids at its facilities.

Dual Feeders

Montgomery County has considered bringing in a separate feeder from a separate sub-station; having the ability to bring in a second feeder could resolve issues such as the microgrid going down or the feeder going down.

FCEBs

One of the reasons that Montgomery County is adding FCEBs to its fleet is that buses with todayʼs BEB technology can only complete 32% of the agencyʼs routesʼ range requirements. Resilience for FCEBs has slightly different components than resilience for BEBs. In addition to providing a backup power source in the event of a power outage, reliable sources of hydrogen supply must be available. Agency staff are looking into multiple sources of hydrogen, including on-site production and delivered sources. The carbon intensity of the hydrogen is also an important consideration for Montgomery County.

Fleet Diversity

Montgomery County has both GILLIG and Proterra buses, BEBs, and will be adding New Flyer FCEBs. The agency expressed that fleet diversification helps mitigate supply chain issues when experienced by original equipment manufacturers (OEMs). Limited manufacturer ZEB offerings are currently affecting the agencyʼs fleet diversification goals.

Microgrid

Montgomery County evaluated implementing a microgrid solution to support its BEBs as a potential measure that would address the key concerns listed above.

Montgomery County noted that when it was first planning to introduce BEBs to its Brookeville facility, it was considering deploying 70 buses, each with a 60 kW charger, with a total load around 4–5 MW. Introducing this size load onto the power grid could have triggered a 5–8-year planning cycle with the local utility. Installing a microgrid reduced the size of the power capacity needed from the utility, accelerating the timeline for installing charging infrastructure.

A microgrid provides multiple benefits for Montgomery County. If an emergency occurs, causing the power grid to go down, even for consecutive days, the microgrid enables the agency to have a source of power for its fleet. Less dramatically, this also allows the agency to be protected against power quality issues or intermittent power on the feeder servicing the site. The microgrid enabled Montgomery County to install charging equipment more quickly, as it reduced the utility load requirements the transit agency had. In addition, because microgrids are not reliant on the fluctuations of utility costs, Montgomery County can fix its costs for a 20–25-year period, which provides the agency with more budget certainty and has the potential to decrease its energy and fuel costs over a longer period of time.

Thermal Event Prevention

To decrease the chances of a thermal event occurring and mitigate the damages if a thermal event occurs, Montgomery County has determined some of the key indicators for thermal events in order for on-site staff to know how to catch the early signs of a fire emergency and take the most effective course of action to maintain safety and mitigate damage as much as possible. Montgomery County has also begun identifying areas where it can isolate equipment in the event of a thermal runaway.

Implementation of Resilience Measures

Resilience measures that Montgomery County has implemented include a microgrid, fleet diversity, contingency ICE fleet, and charger compatibility.

Resilience assessments are a standard component of any capital project Montgomery County undertakes. The threats Montgomery County is exposed to and its required service levels in different scenarios are known. ZE propulsion required new types of adaptation measures to ensure service needs could be met in the event of a threat occurring.

When planning for the microgrid installation, Montgomery County sized the microgrid based on how many buses it needs to operate during its emergency service operation. During an emergency, it is likely that Montgomery County will have to run anywhere between 70 and 100 buses, and the microgrid size was determined based on the power required to charge that many buses.

As part of the microgrid, Montgomery County installed natural gas generation; the agency plans to transition to hydrogen generators in the future so it can utilize both solar and green hydrogen to power its fleet.

One of the challenges with the implementation of resilience measures is funding. Implementing resilience measures can be capital-intensive, and many competitive funding opportunities do not prioritize resilience. Montgomery County used a public-private partnership (P3) model to fund its microgrid. Montgomery County has a 20–25-year energy-as-a-service agreement with partner Alphastruxure that was part of this agreement. Using this approach, Montgomery County did not have to secure significant amounts of capital funds upfront to fully cover the cost of the design, equipment, and construction of the microgrid. Montgomery County also included charging in the agreement. As a result, Alphastruxure is responsible for managing the chargers and ensuring they are available to charge buses. The provider is incentivized to resolve issues with the chargers quickly, as the provider is paid based on the amount of energy provided to the buses. This also reduces the need for Montgomery County to hire and train staff to maintain the chargers, a function that has historically been outside of the key functions of the transit agency. This approach shifts the cost of capitalizing charging infrastructure to an operating cost, thereby freeing up capital funding to cover the increased cost of ZE vehicles and well positions the agency for future grant submissions.

This has been a successful approach for the transit agency, and Montgomery County is in the early construction stage of an additional microgrid at a second facility.

Key Takeaways

Montgomery County provides an example of how existing resilience planning measures and emergency response plans can guide an agency in determining service level needs, a key input to evaluating any adaptation measure.

New York MTA

Zero-Emission Fleet Status

The New York MTA has been working on transitioning its fleet to ZE technologies for a number of years. In 2017, it made a public commitment to transition all 5,800 buses in its fleet across 28 depots to ZE by 2040, and this was followed by the New York Governorʼs office mandating that all state agencies convert their vehicles to ZE technologies.

MTA began exploring ZEB by leasing five 40ʼ BEBs each from New Flyer and Proterra, with charging infrastructure installed at a single depot. These buses were run for 3 years on a trial basis prior to MTA placing a purchase for 15 articulated 60ʼ BEBs. Those buses arrived in New York in December 2019 and are currently in operation in revenue services.

MTAʼs next delivery of BEBs is expected by the end of 2024 (sixty 40ʼ buses), with 470 more arriving in 2025–2026.

Resilience Planning Approach

As part of its ZEB resilience planning efforts, MTA conducted a study that evaluated multiple threats that the fleet might experience. There are six key priorities that have been identified for the potential implementation of adaptation measures. These priorities are:

• Power loss
• Cybersecurity
• Winter storms and extreme cold
• Extreme heat
• Hurricanes (Category 1–5)
• Extreme precipitation/flooding events

MTA is preparing a report on how to best prepare for these events.

Adaptation Measures Evaluated

There are a number of adaptation measures that MTA has explored. There has been significant emphasis on electrical grid resilience, as power loss is the highest priority threat for the MTA to mitigate.

Electrical Grid

MTA has redundancy built into its facilitiesʼ electrical design. All of its facilities have N+2 design architecture, meaning that every facility is supported by two primary feeders.

MTA would like to build out a bus depot pilot project with on-site battery energy storage powered by renewables or energy supplied by the utility during off-peak hours to charge vehicles.

Propulsion Type Diversification

MTA began its transition planning process focused on BEBs. However, the agency is monitoring the hydrogen fuel cell electric bus (FCEB) market as it develops. One way that MTA is viewing the hydrogen fuel cell technology is through the lens of resilience as applied to its six identified priorities. For example, hydrogen fueling stations and FCEBs require a lot less power for operation than BEBs and charging infrastructure. This technology has a lower level of risk associated with it in the event of a power loss.

Implementation of Resilience Measures

MTAʼs biggest efforts toward resilience measure implementation so far have been through its planning efforts.

One of the key components of this is MTAʼs approach to staffing the ZE transition. MTA has a dedicated program manager for the transition to ZEB, and there is an independent group that is managing those efforts. The program manager coordinates with dedicated working groups within individual departments at the agency that follow more classical labor groups in bus transit operations (such as maintenance, bus specifications, facilities, capital planning, operations, procurement, legal, and government affairs).

Another key aspect of planning to have resilience infrastructure is close coordination with the local electric utility. MTA has been meeting with ConEdison bi-monthly since 2020. MTA came to the table with its transition plan outlined, including volumes of buses and total power needs required across all of its depots. The agency has been able to work with the utility to prioritize the locations for upgrades and the timing of those updates. All of the facility designs have some level of redundancy, and MTA is coordinating with ConEdison and the Department of Public Services on transit-specific, ZEB charging rates to increase the affordability of the transition.

Key Takeaways

MTAʼs approach builds upon its existing resilience planning and transition planning efforts to identify key priorities for ZEB resilience. These planning efforts and the execution of any needed implementation are supported by staff focused on the integration of ZEB into MTAʼs fleet. This attitude of recognizing that there are unique characteristics of ZEBs and supporting infrastructure, but that the foundation of resilience planning is the same for ZEBs and conventional technologies, has been the foundation for MTAʼs successes in resilience planning for ZEBs.

Santa Maria Regional Transit

Zero-Emission Fleet Status

SMRT is committed to transitioning to a fully ZEB fleet sooner rather than later. As of April 2024, SMRT had two Proterra buses, six electric vans, and 14 electric minibuses. The agency had an order placed for four more Proterra buses, but the order is currently suspended until SMRT receives more information about how Proterra operations have transitioned to Phoenix Motorcars. In addition, SMRT had transit buses from New Flyer, GILLIG, KARSAN eJest, and paratransit vehicles from Lightning eMotors on order. The agency will be receiving many of these buses by the end of 2024 and early 2025, although deliveries have been delayed due to production and supply chain issues. With the addition of these vehicles, SMRT will more than likely have a 100% ZEB fleet, including paratransit, by the middle of 2025. The fleet will consist of 22 full-size buses, six vans, and 15 minibuses. This is well ahead of the California Air Resources Boardʼs Innovative Clean Transit Regulationʼs 2040 target.

Resilience Planning Approach

Although SMRT does not currently have many ZEBs in its fleet, this has not prevented the agency from evaluating compatible resilience measures and starting the implementation process. SMRT has approached this from the dual perspectives of ensuring maximum reliability and uptime of the fleet based on todayʼs market, and is in the process of evaluating a hazard analysis plan.

Key Concerns

SMRT identified several key concerns, largely related to reliance on a single bus or charger OEM, charger availability, charger space requirements, potential issues related to software updates, and potential power outages, particularly those caused by a localized grid issue that could result in a prolonged power outage that would limit the agencyʼs ability to meet service demands.

Threats

SMRT identified earthquakes as the most significant environmental threat to its operations.

Subsequent and related power outages are a significant threat to SMRTʼs ability to provide service, and many of the adaptation measures it is implementing are to mitigate that threat.

Responsibilities During an Event

SMRT is part of the municipal government, and the agency is identified as an organization that must provide support in the event of a large-scale disaster. Other life safety-related departments within the city would direct SMRT as to where vehicles are needed to support the emergency response.

In the event of supporting an evacuation effort, SMRT will not likely be expected to transport residents further than across town. However, it has some ability to evacuate residents to neighboring communities if directed to do so.

Adaptation Measures Evaluated

SMRT has evaluated a number of different strategies for increasing the resilience of its ZEB fleet, including maintaining an ICE contingency fleet, diversifying charging locations, and maintaining multiple bus models within the fleet.

Software Updates

SMRT mentioned that it is important to keep its bus chargers up to date and verify that software updates have successfully been installed to maintain operations. The agency plans to install updates to a limited quantities of vehicles and chargers first to ensure functionality has been maintained before rolling out updates across its entire fleet. This will ensure that there are viable vehicles and chargers available for service should any updates cause unexpected issues.

Opportunity Charging

SMRT is considering incorporating opportunity charging to be located at an additional but separately located redundancy site that would allow the agency to fuel buses off-site if a local issue caused a prolonged power outage at the main staging depot.

SMRT is also collaborating with neighboring cities on shared charging sites, so the agency will have the ability to utilize various locations outside its immediate area for charging if needed and vice versa. Depending on what each entityʼs needs are, they can help each other out and ensure they are able to meet their service needs.

Implementation of Resilience Measures

SMRT has begun implementing a number of resilience measures to ensure the success of its future ZEB fleet, including fleet diversification, dual port chargers, training, redundancy sites, utilizing third-party expertise, and an ICE contingency fleet.

Fleet Diversification

As agencies are transitioning to ZEB, they are diversifying their fleets with multiple vendors. SMRT is taking this same approach in order to avoid having to depend on only one bus manufacturer. For example, if supply chain issues occur and a bus manufacturer is not able to send needed bus parts to SMRT in a timely fashion, the agencyʼs services could be impacted. This impact is mitigated by having multiple bus models in the fleet. SMRT currently has orders for ZEB from Proterra (now Phoenix Motorcars), New Flyer, Lightning eMotors, and the KARSAN eJest.

Dual Port Chargers

SMRT has dual-port chargers (CP3). The agency is able to pair the chargers through a setting to increase the charging power if needed. This provides resilience in the event of an emergency, where service needs may be less predictable, and buses may need to charge as quickly as possible.

Redundancy Sites

SMRT is currently building a redundancy site to house some of its plug-in charging infrastructure and use as a remote transit yard. To help improve resilience in the event of grid issues, SMRT hopes to place this new yard on a separate primary feeder from its current depot. SMRT will likely have multiple sites to house ZEBs and infrastructure.

ICE Contingency Fleet

SMRT plans to have a backup diesel contingency fleet when it transitions to a fully ZEB fleet. SMRTʼs diesel vehicles will not have reached their end of life before SMRT phases them out of regular operation. For this reason, SMRT will be able to retain its diesel vehicles longer, and they should still work very well in the event of emergencies.

SMRT said that in order to receive funding for an ICE contingency fleet, agencies have to present a plan to FTA on how they will maintain their fleet and utilize it in the event of emergencies. SMRT has also worked with FTA to communicate that the BEBs do not have the same range capabilities as diesels and apply spare ratio requirements for SMRT accordingly.

Key Takeaways

SMRT is an example of a smaller agency with aggressive ZEB transition goals that is being proactive about resilience planning and is leveraging its experience with early ZEB deployments to address issues with earlier deployments from becoming catastrophic when it has a fully ZEB fleet. By planning for shared redundant charging stations, SMRT is also an example of integrating transit resilience planning into larger regional planning efforts.