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4Project Background and Objectives Transportation accounts for 28.5% of U.S. energy consumption and petroleum accounts for 91.5% of the transportation energy consumption in 2015. In 2014, buses consumed 98,000 barrels of petroleum per day or 413 million gallons of diesel over the year. This is equivalent to more than 4 million tons of carbon dioxide emissions in one year. In 2014, all highway vehicles accounted for 22.26 million tons of carbon monoxide, 4.49 million tons of nitrogen oxides, 2.16 million tons of volatile organic compounds, and 470,000 tons of particulate matter emis- sions (Davis et al. 2016). Reducing emissions and reliance on petroleum from the U.S. transpor- tation sector is seen as an important step in realizing health benefits, reducing global warming effects, improving national security interests, and creating jobs. Battery electric buses or BEBs, also known as all-electric buses, do not rely on petroleum for operation and have zero tailpipe emissions. BEBs are also attractive to transit agencies because they have proved to be quieter, simpler, and smoother than their conventionally fueled counter- parts due to all-electric propulsion and auxiliary systems. These attributes result in zero tailpipe emissions (including zero local criteria air pollutants and carbon emissions), zero dependence on foreign oil, better ride quality and experiences for passengers and drivers, and potentially lower operational costs. However, there are still challenges associated with the technology, includ- ing range limitations, long charging times, potentially high electricity rate charges (including demand charges), and higher capital costs. These challenges are being accommodated through a wide range of approaches, including improved planning methods, making operational changes (e.g., bus blocking and layovers), increasing the amount of resources (including number of chargers and/or buses), and striving for technology improvements. Ultimately, many of these challenges are expected to be addressed or mitigated through battery improvements with respect to costs, energy density, power density, and charge rate acceptance. As a result of the broad range of benefits, transit agencies are purchasing BEBs on a much larger scale than ever before and more and more BEB products are being introduced to market. A discussion about BEBs begins with the fundamental differences between them and conven- tionally fueled diesel and compressed natural gas (CNG) buses. BEBs are driven using an electric motor rather than an internal combustion engine and therefore are also referred to as an âelec- tric driveâ vehicle. Fuel cell and series hybrid electric vehicles (EVs) are also considered electric drive vehicles for the same reason. However, for BEBs, all of the energy used by the vehicle to power the traction motor and auxiliaries comes from the energy stored in an electrochemical battery pack. Compared with diesel, CNG, fuel cell, and hybrid technologies, all-electric vehicles significantly reduce the amount of energy conversion on board the vehicle and use very effi- cient electrical power conversion components to power the driveshaft and auxiliary systems, such as lighting and air conditioning. This is the simplest, most efficient, and cleanest method C h a p t e r 1 Introduction
Introduction 5 of powering a vehicle. While a fuel-cell-powered vehicle is also a zero emission, electric drive vehicle, it adds hydrogen energy storage and the fuel cell to convert hydrogen to electricity to be stored in the batteries and power the vehicle. This additional energy conversion step, while clean, is roughly 50% to 55% efficient and results in additional energy losses. The benefit of fuel cell technology is its ability to store more energy on board the bus and provide longer ranges than BEBs. Fueling with gaseous hydrogen as opposed to charging is also a faster way to add energy to the vehicle. A diesel or CNG series hybrid bus also works like a fuel-cell-powered bus but in this case the energy conversion efficiency of the engine is only 35% to 45%, resulting in greater energy losses in addition to the vehicles having tailpipe emissions (U.S. Environmental Protection Agencyâs National Vehicle and Fuel Emissions Laboratory 2017). Also diesel and CNG powered vehicles require that the engines are running during stops and brief idling, further reducing their efficiency. Finally, conventionally fueled buses without energy storage on board are not able to recover energy from regenerative braking, also further reducing vehicle efficiency. Ultimately, the U.S. Environmental Protection Agency states that only about 14% to 30% of the energy from gasoline put into conventional passenger vehicles (using combustion engines) is used to move it down the road while all-electric vehicles used 74% to 94% of the electricity put into the vehicle to move them down the road (Fueleconomy.gov 2017). Altoona Bus Testing reports provide a convenient way to compare overall fuel economy specifically for transit buses. The Altoona Bus Research and Testing Facility provides testing for all new bus models under the Federal Transit Administrationâs (FTAâs) bus testing pro- gram. âThe programâs goal is to ensure better reliability and in-service performance of transit buses by providing an unbiased and accurate comparison of bus models through the use of an established set of test proceduresâ (The Altoona Bus Research and Testing Center 2015). Evaluation of tests across New Flyerâs Xcelsior 40â² low floor bus platform provides a basis for a direct comparison of all four propulsion methods: diesel, CNG, hybrid-electric, and all- electric. The measured fuel economy for each technology is converted to the miles per diesel gallon equivalent (MPDGE) value to allow for comparison. As shown in Figure 1, the electric 0 5 10 15 20 25 30 CBD Arterial Commuter Average Fu el E co n o m y (M PD G E) Electric Bus CNG Diesel Hybrid Figure 1. Altoona measured fuel economyâNew Flyer buses. Source: Center for Transportation and the Environment.
6 Battery electric BusesâState of the practice bus fuel economy far exceeds the CNG, diesel, and hybrid bus fuel economy in every test track phase. The average fuel economy for the electric bus (20.5 miles per diesel gallon equiva- lent [MPDGE]) is greater than four times the average CNG (4.8 MPDGE) and average diesel (4.8 MPDGE) fuel economies, and just under four times more efficient than the average hybrid bus (5.84 MPDGE) fuel economy. Description of Bus Charging Methods Deployment of BEBs requires careful consideration of deploying the associated charging infrastructure. A topical understanding of power and energy is important when considering and comparing BEBs and their charging systems. Energy is the property that must be transferred to an object in order to perform work on the object. In this case, electrical energy is being consid- ered and will use the units of kilowatt hours (kWh). Power is the amount of energy consumed per unit time and can be expressed in SI units of watts or kilowatts (kW). BEBs are âfueledâ through charging. Three types of charging are used for BEBs in the United States today: plug-in charging, overhead conductive charging, and wireless inductive charging. The attributes, pros, and cons of each type are highlighted below. 1. The attributes of plug-in charging (manually plugging in the vehicle to a power supply) are as follows: â Typically installed at the depot, shop, or garage. â Typically used to charge overnight. â Typically used as sole charging method for buses with large battery packs and higher range. â Charge type: AC or DC. â Charge power: 40â120 kW. â Recharge times (depending on charge power and battery pack size): 1â8 hours. â Applicable U.S. Standards: SAE J1772; SAE J3068 (in progress). The pros of plug-in charging are as follows: â Minimal infrastructure and installation requirements. â Lower cost per charger than other options. â Able to take advantage of lower off-peak electricity rate when charging overnight. â More flexibility for route selection and future route changes. The cons of plug-in charging are as follows: â Buses must be taken out of service to charge. â Buses use larger, heavier battery packs that can reduce bus efficiency, reduce passenger capacity, and increase wear on suspension components. â Charging process is manually intensive (plugging in and monitoring). â Charging is typically slower than other options. â Charging can require a lot of space with a charger for each bus. â Charging can require a lot of power with each bus charging at the same time. 2. The attributes of overhead conductive charging (automated connection using an overhead conductive coupler) are as follows: â Typically installed on route or at transit center where layovers occur, allowing for oppor- tunity charging; may also be installed at the bus depot or yard. â Typically serve multiple BEBs operating on routes or from transit centers. â Typically used with buses with smaller battery packs and less range. â Charge type: DC. â Charge power: 175â450 kW. â Recharge times: 5â20 minutes. â Applicable U.S. Standards: SAE J3105 (in progress).
Introduction 7 The pros of overhead conductive charging are as follows: â Buses use smaller, lighter battery packs. â There is full-range charge in 5â20 minutes. â Can support 24-hour bus operation if implemented correctly. The cons of overhead conductive charging are as follows: â Higher cost of charging infrastructure. â Requires charging infrastructure, equipment, and civil work. â Peak demand charges can significantly affect operational costs. â Land use and/or rights must be obtained at deployment sites. â Overhead systems may interfere with road clearances or require dedicated/restricted pull-off. â Fixed infrastructure constrains route changes for BEBs in the future or can be costly to relocate. 3. The attributes of wireless or inductive charging are as follows: â Typically installed on route or at transit center where layovers occur but could also be used at bus depot. â Typically serve multiple BEBs operating on routes or from transit centers. â Typically used with buses with medium-to-large battery packs and medium range. â Charge power: 50 kW (up to 250 kW planned). â Applicable U.S. Standards: SAE J2954/2 (in progress). The pros of wireless or inductive charging are as follows: â Can remain in service while charging on route. â Decreased infrastructure footprint. â Charging interface does not interfere with road clearances or require dedicated/restricted pull-off. â No manual connection or moving parts. The cons of wireless or inductive charging are as follows: â Slightly less efficient than conductive methods (90% versus 95%). â Higher cost of charging infrastructure. â Requires charging infrastructure, equipment, and civil work. â Peak demand charges can significantly affect operational costs. â Land use and/or rights must be obtained at deployment sites. â Fixed infrastructure constrains route changes for BEBs in future or can be costly to relocate. BEB History and Development In the mid to late 1990s and early 2000s, a wave of BEBs hit the United States with transit agen- cies in Santa Barbara, California; Chattanooga, Tennessee; and Tempe, Arizona, ordering BEBs from start-up BEB manufacturers, including AVS and Ebus. Due largely to the bankruptcy of AVS and to the poor performance of lead acid and NiCad battery technologies at the time, the BEB industry stalled from about the years 2000 to 2010. Led by the success of start-up manu- facturer, Proterra, the BEB industry saw resurgence around the turn of the decade. Proterraâs early success was followed closely by BYDâs introduction to the U.S. market. The major North American bus original equipment manufacturers (OEMs) followed suit when New Flyer built upon their extensive electric drive experience (including trolleys and hybrid buses) to develop and offer all-electric bus products. NovaBus followed suit and, most recently, GILLIG began offering a BEB product. Complete Coach Works also introduced a remanufactured bus product complete with an all-electric drive system. The resurgence of the U.S. BEB industry was largely due to FTAâs investment into electric drive technologies with programs including the National Fuel Cell Bus Program, the Transit Investments for Greenhouse Gas and Energy Reduction (TIGGER) Program, the Clean Fuels Grant Program, and the Low or No Emission Vehicle
8 Battery electric BusesâState of the practice Program. The National Fuel Cell Bus Program helped develop new fuel cell, electric drive proto- type vehicles. The other programs have helped to offset the higher capital costs of BEBs, thus enabling more transit partners to deploy. In addition to FTAâs programs, the Fleet Rule for Transit Agencies from the California Air Resources Board (CARB) has helped spur the market by requiring that urban buses meet stricter California exhaust emission standards. Figure 2 highlights the growth in the U.S. zero emission bus market since 2009. From 2009 through 2016, the total number of BEBs awarded, contracted, and/or sold in the United States grew from 17 to 582, while the number of fuel cell electric buses grew from 35 to 76. There are approximately 78 BEB deployments planned or deployed in the United States and 72 of those are public transit operations, with the remaining being universities and private fleets, as shown in Table 1. Approximately 35 agencies out of the 72 have deployed BEBs and the vehicles are operating in transit service. In early 2017, King County Metro announced an individual order for 73 BEBs. One transit operator has successfully converted its full fleet to all-electric and mid-size California transit agencies are committing to convert their entire fleets to BEBs as well. Nine companies are currently manufacturing BEBs. Some are focused on a full suite of vehicle types, including conventionally powered to electric drive while other OEMs are solely manufacturing BEBs. As shown in Table 2, the OEMs offer a wide range of BEB and charging configurations geared toward meeting the unique individual needs of a variety of agencies. The wide variety of bus configurations and charging options provided by the bus OEMs are designed to meet a variety of deployment scenarios with range and charge time limitations. Transit agencies must consider their unique characteristics and needs when planning, procur- ing, and deploying BEBs and the associated charging infrastructure to determine the appropri- ate configuration and charging options best suited to their deployment. These characteristics include â¢ route demands (speeds, grades, stops, length, layovers); â¢ bus service or blocking demands (deadheads, duration, and frequency); â¢ seasonal temperatures; 0 100 200 300 400 500 600 700 Year 2009 2010 2011 2012 2013 2014 2015 FCEB BEB Figure 2. U.S. zero emission bus cumulative sales and awards. Source: Center for Transportation and the Environment.
Introduction 9 Modesto Transit 1 4 Monterey Salinas Transit 2 3 Mountain View Transportation Management Association (MVGo) 1 4 Nashville Metropolitan Transit Authority 1 9 Navajo Transit System 1 1 Park City Transit 1 6 Fleets with BEBs Awarded, On Order, or Deployed # of Deployments Total # of BEBs AC Transit 1 5 Albuquerque Rapid Transit 1 18 Anaheim Transportation Network (ART) 1 4 Antelope Valley Transit Authority 2 41 Ben Franklin Transit 1 1 California State University- Fresno 1 3 Capital District Transportation Authority 1 1 Central Contra Costa Transit Authority (CCCTA) 2 8 Chattanooga Area Regional Transit 1 3 Chicago Transit Authority 2 6 City of Columbia (COMO Connect) 3 16 City of Fresno 1 2 City of Gardena (GTrans) 2 6 City of Seneca 1 7 Clemson Area Transit 1 10 Dallas Area Rapid Transit (DART) 1 7 Delaware Transit Corporation 1 6 Denver RTD 1 36 Duluth Transit Authority 1 7 Everett Transit 1 4 Foothill Transit 3 31 Frederick County (TransIT) 1 5 Fresno County Rural Transit Agency 1 4 Hartsfield Jackson Airport 1 2 Indianapolis Public Transportation Corporation (IndyGo) 1 21 JLL Jones Lang LaSalle 1 10 King County Metro 3 84 Kitsap Transit 1 1 Lane Transit District 2 10 LEWT - Napa Valley Wine Tour 1 1 Link Transit 4 20 Long Beach Transit 2 13 Los Angeles Dept of Transportation 1 4 Los Angeles Metro 1 5 Massachusetts Bay Transportation Authority 1 5 Metro McAllen 1 2 Metro St. Louis 1 1 Miami-Dade County 1 4 Table 1. Current BEB deployments in the United States. (continued on next page)
10 Battery electric BusesâState of the practice â¢ passenger loads; â¢ available garage space and power; â¢ layover or transit center locations and space; and â¢ utility rate schedules and costs. Agency characteristics must be evaluated collectively and in conjunction with the various bus configurations and charging options as they affect the performance (specifically range), capital, and operating costs for BEBs. For instance, hot or cold temperatures can have a significant effect on air conditioning or heating loads, bus efficiency, and range, whereas the time, length, and amount of charging can have a significant effect on demand charges and total energy costs. Fleets with BEBs Awarded, On Order, or Deployed # of Deployments Total # of BEBs Pierce Transit 1 2 Pioneer Valley Transit Authority 1 3 Port Arthur Transit 1 6 Porterville Transit 1 9 Quad Cities Metrolink 1 2 Regional Transit Agency of Central Maryland (Howard County) 1 3 RTC (Reno Regional Transportation Commission) 2 8 San Joaquin Regional Transit District 4 11 Santa Barbara MTD 1 2 Santa Catalina Island Company 1 3 Santa Clara Valley Transportation 1 5 Santa Cruz Metropolitan Transit District 1 3 Shreveport Area Transit System (SporTran) 1 5 Solano County Transit (SolTrans) 1 2 Sonoma County Transit 1 1 Southeastern Pennsylvania Transportation Authority 1 25 Stanford University 2 39 Star Metro 1 6 SunLine 1 3 Thunder Bay Transportation 1 4 Transit Authority of Lexington (Lextran) 2 6 Transit Authority of River City (TARC) 2 16 Tri Delta 1 2 Tri-County Metropolitan Transportation District of Oregon (TriMet) 1 4 Twin Transit 1 1 UCLA 1 2 Univeristy of California Riverside 1 1 University of Georgia 1 19 University of Montana 1 2 Utah Transit Authority 2 6 VIA Metro 1 3 Visalia Transit 1 2 WMATA 1 1 Worcester Regional Transit Authority 1 7 Grand Total 102 655 Count 78 568 Table 1. (Continued).
Bus Manufacturer Model Style Infrastructure Energy Storage K7 30â² transit bus 80 kW Depot Charge 182 kWh K9, K9S 40â², 35â² transit bus 80 kW Depot Charge 324 kWh K11 60â² articulated transit bus 200 kW Depot Charge 547 kWh C6, C9, C10 23â², 40â², 45â² coaches 100-300 kW Depot Charge 135-394 kWh CCW ZEPS 40â² transit bus Depot Charge 213-242 kWh Double K Villager 30â² trolley Depot Charge Ebus 22â² city bus Depot Charge Ebus 40â² transit bus On Route Charge 89 kWh Gillig Standard LF 29â² transit bus Depot/On Route Charge 100 kWh Green Power Varies 30â²-45â² Depot Charge 210-478 kWh 99 kWh 198 kWh 297 kWh 60â² transit bus Depot/On Route Charge 250 kWh Nova Bus LFSe 40â² transit bus On Route Charge 76 kWh 79 kWh 105 kWh 220 kWh BYD Ebus New Flyer Excelsior 40â² transit bus Depot/On RouteCharge Proterra Catalyst FC 35â², 40â² transit bus On Route Charge Catalyst XR 35â², 40â² transit bus Depot/On Route Charge 330 kWh 440 kWh 550 kWh 660 kWh Catalyst E2 Source: Center for Transportation and the Environment. 35â², 40â² transit bus Depot Charge Table 2. BEB manufacturers and products.
12 Battery electric BusesâState of the practice There is no one-size-fits-all solution with BEBs and charging infrastructure; thus procurement and planning decisions must be made carefully based on the individual needs and characteristics of the transit agency in order to achieve and maximize the benefits of all-electric technology. To date, agencies have relied on high-level information as well as on trial and error to make decisions regarding BEB deployment. However, detailed analyses and tools are beginning to emerge to assist agencies in making objective, data-driven decisions. Additionally, most BEBs are being deployed on the least demanding routes and bus blocks in order to mitigate any risks to service. As the boundaries for BEB service are pushed, the need for information and tools to ensure that service can be met and deployments are cost effective will become even more critical. No two business cases or BEB deployments have been exactly alike. The pioneering effort of each agency that has chosen to deploy BEBs has contributed significantly to the body of knowledge. The following sections highlight these deployments and lessons learned contributing to more informed deployments of BEBs and mass adoption by the transit industry. This synthesis report is intended to be a resource for transit agencies looking to procure and deploy BEBs for the first time, as well as for experienced agencies to learn what others are doing and adopt best practices in their current and future BEB fleets. Technical Approach To document the current state of the practice of BEBs, three approaches were taken to col- lect, organize, and present data on BEB deployments. First, a literature review was performed; second, a comprehensive survey of experienced agencies was completed; and third, case exam- ples involving five agencies provided a more in-depth examination of their BEB deployment experience. The literature review section is organized to address the following topics. Planning â¢ Life cycle cost analysis; â¢ Bus technical specifications, operational requirements, and route selection; â¢ On-route charging infrastructure; â¢ Layover location characteristics; â¢ Electricity rate structure; â¢ Planning and support tools; and â¢ Scalability. Service, Maintenance, and Operations â¢ Training (maintenance, operators, first responders, and dispatching systems); â¢ Availability and reliability of buses; â¢ Resiliency and emergencies; â¢ Equipment longevity and risk mitigation (vehicles, battery, chargers, and unknowns); â¢ Technology for managing, charging, and dispatching; and â¢ Stakeholder involvement (utilities, operators, unions, communities, executive boards, regula- tory agencies, and so forth). Costs and Benefits (What benefits at what costs?) â¢ External funding opportunities (federal funding, carbon credits, and so forth); â¢ Customer acceptance; â¢ Social; â¢ Environmental;
Introduction 13 â¢ Health; â¢ Cost of energy (utilities); and â¢ Return on investment. Research into relevant literature included a Transport Research Information Documentation database search using the keywords âbattery electric busâ and other relevant terms. This search was augmented with other pertinent materials collected from industry-related sources and web sources. The survey questions were established to address the broad scope of synthesis topics using established survey methods. Based on actual BEB deployment experience and industry input, the questions are both quantitative and qualitative. Twenty-one transit agencies were surveyed to represent a wide range of BEB experience, agency size, agency location, OEMs, and bus and charging technology types. The survey was structured in a time-based manner to reflect the process an agency undergoes to accomplish a deployment project. This was partly done to get the respondents thinking through the process of procuring and deploying their BEBs and partly because the respondents were all at different stages of the process. The approach considered two stages: (1) planning and (2) experience after deployment. The planning stage addressed the events and considerations leading up to actually placing the BEBs in service and included assess- ment of procurement and preparation. The experience after deployment stage provided insights into the experience and results from active deployment, including assessment of operations, maintenance, and administration impacts as well as actual costs and benefits. Finally, five transit agencies representing a variety of locations and experience were inter- viewed for case examples. These interviews added an additional layer to the state-of-the practice assessment; the agencies reported their challenges, solutions to those challenges, and advice to other agencies. Content Organization The report is organized as follows: â¢ Chapter 1 provides the background and introduction into the study. â¢ Chapter 2 provides the results of the literature review and attempts to characterize the current state of available information regarding BEB deployment experience. â¢ Chapters 3 through 5 provide the survey results. The survey results section is split into three separate parts, based on the category of each question. Chapter 3 of this synthesis report is the first of the survey results and provides general information about the agenciesâ character- istics and BEB fleets. Chapter 4 delves into the planning aspect of BEB deployment, address- ing life cycle cost analyses, bus technical specifications and operational requirements, route selection, infrastructure planning, standards and interoperability, scalability, and other bus and infrastructure capabilities. Chapter 5 presents the agenciesâ postdeployment experience, addressing training, operations, charging specifics, service and maintenance, availability, stakeholders, electricity rate structure, public perception, and overall satisfaction with BEBs. â¢ Chapter 6 presents case examples of five agencies that have deployed BEBs and charging infrastructure. â¢ Chapter 7 provides a summary of major synthesis findings and suggestions for future research. â¢ Appendix A is the survey questionnaire and Appendix B provides the full survey details.