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Issues of the Environment: Ann Arbor Area Transportation Authority moving forward to become entirely zero emission

Matt Carpenter, CEO of the Ann Arbor Area Transportation Authority
Sean Carter
Matt Carpenter, CEO of the Ann Arbor Area Transportation Authority


  • Ann Arbor’sA2Zero plan is targeting net carbon neutrality by 2030 through various actions and one of those actions includes transitioning TheRide’s fleet to zero emission vehicles. The A2Zero plan estimated that TheRide’s fleet commits about 10,700 tons of CO2 equivalents or greenhouse gas emissions annually, which is about half a percent of the region's total emissions. The A2Zero plan reveals that TheRide’s fleets contribute less than 1% of the region's GHG emissions.
  • Currently, the AAATA is weighing the community priorities of expanding services and ridership vs. reducing emissions to combat climate change. Doing both full speed is not likely feasible financially. In November 2022, the AAATA sought input from the public regarding these priorities, as well as which choice of technology forZero Emission Buses (battery-electric buses and hydrogen fuel cell electric buses) is most prudent. The biggest hurdle for either technology is related to range limits, especially in cold weather, because AAATA covers a large service area, which includes all of Ann Arbor and Ypsilanti.
  • Both options for Zero Emission Buses (ZEB) require significant investments estimated to be at least $75 million in up-front costs over and above business as usual costs to purchase buses and overhaul the fueling garage from diesel to the new format. 
  • In summary, battery-electric buses use onboard batteries to power a motor, are generally less expensive to maintain, but the technology is less developed than for hydrogen fuel-cell buses. Historically, they are cheaper to fuel than diesel buses, partly because of the volatility of diesel costs compared to the stability of electricity costs, but there is a risk that electricity costs may rise. The standout drawback for BE buses is related to operating range limitations, which AAATA modeling estimates that about 62% of the ride service could be feasible in cold weather and therefore the ride would need to rethink how to deliver a service on cold days, which may include redesigning service, rescheduling buses, as well as increasing the bus fleet.
  • Hydrogen fuel-cell buses are the other option on the table. They have an on-board hydrogen tank that is used to create electricity to power the motor. Hydrogen buses have longer operating ranges compared to BB's but still less than fossil fuel buses. Our modeling showed that 90% of the rides service can be operated in cold weather conditions, showing that this technology provides a greater range of service. Although they tend to be cheaper to maintain, hydrogen fuel costs are higher, and a much more extensive overhaul of the garage would be needed. 
  • According to the AAATA, overall, adopting ZEBs could reduce AAATA’s fleet-based carbon footprint by 27-50% over a 12-year timeframe, which translates to a community-wide emissions reduction of less than 0.5%. In addition, the conversion could also eliminate 16,000 kg of nitrous oxide (NOx) and 113 kg of particulate matter (PM) per year. Further greening of the electrical grid, as well as green hydrogen sources, together with a 100% ZEB fleet will reduce the carbon footprint even further.
  • Another consideration is the “greenness” of the source fuel. DTE still uses a good deal of coal and natural gas to generate electricity, and heating on E-B buses requires burning diesel for a space heater, rather than harvesting heat as a byproduct of combustion from the engine. Conversely, the hydrogen supply line is still being built out with varying degrees of environmental “dirtiness” depending on the source. 
  • Matt Carpenter, Chief Executive Officer (CEO) for the Ann Arbor Area Transportation Authority (AAATA), notes that It's important to note that the state of Michigan has no mandate to transition to zero emission buses, and neither does the federal government. However, the federal government, through the Federal Transit Administration, has increased the amount of competitive funding available for acquiring ZEB’S to combat air pollution, particularly in historically disadvantaged neighborhoods. Some funding could come through the Inflation Reduction Act


David Fair: This is 89 one WEMU. And today, we're going to talk transportation on this week's edition of Issues of the Environment. I'm David Fair. And we're going to specifically look at public transportation as it, too, is moving to a more sustainable future. The Ann Arbor Area Transportation Authority is examining its role in helping Ann Arbor meet its carbon neutrality goal by 2030 and Washtenaw County's goal of hitting neutrality by 2035. That means changes in the kinds of busses TheRide uses in its fleet. But there are choices to be made and challenges to overcome. Our guest this morning is in the thick of the decision making process. Matt Carpenter is the CEO of TheRide. And thanks for the time today, Matt. I appreciate it.

Matt Carpenter: Thank you, David. Thank you for having us.

David Fair: Let's get a baseline. How big is TheRide's fleet right now?

Matt Carpenter: Our fixed-route bus fleet is about 103 40-foot, low-floor urban transit busses. We also have about ten paratransit busses. Those are the shorter vehicles that go door-to-door.

David Fair: And almost exclusively diesel or fossil fuel driven. Correct?

Matt Carpenter: At this point, yes. Although, we still have a sizable number of hybrid busses, much like the hybrid cars of a few years ago. They are a dual propulsion mode, but they do run on diesel fuel to power the electric batteries.

David Fair: What you've been looking at is the pros and cons of fully battery-powered electric busses and hydrogen fuel cell busses. There are advantages and challenges to both. What, in your exploration, have you found to be the best parts of potentially switching to all-electric?

Matt Carpenter: So, it's a really exciting opportunity, and we know how important climate action is to all of the people in our communities that we serve. And it's certainly very important to our board, and they've given the staff pretty clear direction that they want. They want us to go out and figure out how we could help reduce, you know, climate impact as much as possible. And there's kind of too broadways that we can do that. First of all, you know, attracting as many people out of their cars as we can. And we do that by providing frequent, affordable, reliable transit service throughout the Ann Arbor/Ypsilanti area. And that's something we definitely want to continue to grow. It may actually be our most impactful way of reducing air pollution and carbon emissions. The other side of this is reducing the footprint of our own base of operations, and that means beginning to shift away from fossil-fueled, internal combustion engines towards truly zero emission. So, we've begun looking at two zero emission modes of propulsion, and this is zero emission from the tailpipe to start with, as battery electric and hydrogen electric busses. We completely understand that upstream, you know, the electricity, you know, maybe still generates if it's generated by coal or natural gas, there is an upstream impact. Same thing with hydrogen. We understand that. But we're taking kind of a long term look at it and saying, "You know, if we can begin to transition our fleet now, maybe in a few years, those upstream energy generation sources will have gotten better, and we can meet them in the future to have a truly zero emissions impact." With the two technologies that we're considering, one of them is fully battery electric, and the other is hydrogen plus battery electric. The battery busses are very common. We see them in many places right now, but they're being deployed at a very small scale, only a few busses in each agency. And their utility, we're discovering, is a little bit limited because for these heavy duty vehicles, it's important to understand that they're very different than a personal car. You know, a personal car maybe gets driven 45 minutes in the morning. You can plug it in until lunch, drive it again, plug it in in the afternoon until you go home and charge it overnight. A heavy duty transit bus can be in continuous operation for 16 hours a day and leave the garage at 5 a.m. and not come back until 1 a.m.. And during that period, we would have two or three drivers operating it. And, in the winter, like it is snowy today, it has to heat the passenger compartment as well. That is a very different duty cycle. It draws a lot more voltage out of the battery system than a light duty car would. So, what we've discovered through this research is that the battery electric busses that are on the market today, on a cold day, would run out of juice about two-thirds of the way through their operating cycle through the day. So, that's a fundamental challenge with that technology. There are workarounds that can help, but they're very expensive, and they increase the complexity and likelihood of failure of the system. And there's also a lot of hope over the next several years that the battery technology will simply improve and allow the vehicles to stay out on the road a whole lot longer. So, that's kind of an example of where we're kind of on the cutting edge of this discussion, and some of the answers we need to make a fully informed decision and won't be available--

David Fair: Are years away.

Matt Carpenter: Yeah, there are a couple of years away. The hydrogen busses have been around a little bit longer, and they have the added benefit of greater energy density in the fuel tank. They can carry more room, if you will, and keep the bus out there for a full day. And they generate heat naturally from the fuel cell. So, that can help heat the passenger compartment. So, they're a little more practical today. However, they have their own drawbacks, and one of those is a bigger upfront cost to invest. So, there are pros and cons to both technologies. And what we're doing right now is we're just shopping that information around the community, frankly, kind of geeking out on it. It's pretty cool to us to learn this material. We want to share that enthusiasm with the community and ask everybody, you know, what their thoughts are after they've, you know, read our reports, watch the videos that we have, and offer us their feedback and what would they think we should do.

David Fair: 89 one WEMU's Issues of the Environment conversation with Matt Carpenter continues. Matt is CEO of the Ann Arbor Area Transportation Authority. Now, if I'm not mistaken, Matt, a switch to either electric or hydrogen busses would not only require fleet transition, but significant changes in your infrastructure. How would that change what you have to accomplish?

Matt Carpenter: You're absolutely right, David. One of the things we've learned through this research and discussions with other transit agencies is that this is not something you can just jump into. It has significant effects. You know, when you have a fleet as large as ours where there's no margin for error, that bus needs to go out at 6 a.m.. It needs to go out at 6 a.m., not 6:05, not 6:10. So, there's a fleet management scaling issue here as well. So, either option, battery electric or hydrogen electric, will require considerable renovations and expansions and changes to our main garage facility on South Industrial Highway in Ann Arbor. For an electrical thing, there's a lot. We have a 1984 wiring in the building. We're going to have to do some serious upgrades. We'll have to expand the building's footprint to put in a whole new, much larger electrical room. We'll have to work with DTE or whomever the electrical utility is to expand probably the grid in the nearby area. A lot of infrastructure in the building as well, possibly really advanced fire suppression systems. One of the things we've learned and seen is lithium ion batteries have begun to develop a real bit of a reputation as being something of a fire hazard. There's been some unfortunate incidents at busses, bus facilities, and even with the electric scooters where fires have spontaneously started. And it can be very difficult to extinguish when a battery starts burning. So, that's something that would require a lot of thought.

David Fair: Probably pretty touching on your insurance bill every year or two.

Matt Carpenter: You know, that's definitely something we would have to look at. Something got away from us in a tight garage where the busses are packed overnight at 3 a.m. That could be a real concern about service, continuity, and our ability to meet the needs of the community the next morning. Hydrogen also would require whole new fuel tank deliveries of hydrogen, possibly in the future our own electrolysis plant to make fully green hydrogen. But all that takes a lot of space and renovations to the building as well. The electrical busses--you can do sort of charging like en route. There are ways of doing sort of automatic overhead charging, but they represent their own costs and complications as well.

David Fair: We're talking with the CEO of TheRide, Matt Carpenter, on 89 one WEMU's Issues of the Environment. Now I fully understand that accurate budgets can't be completed until more decisions are made and plans finalized. However, you have to have some estimates on what it may take to even start and then ultimately finish the full transition. What kind of needed investment are we looking at, just upfront, to begin the process?

Matt Carpenter: Yeah. There's considerable investments, particularly from a capital perspective, needed to get started. And one of the things we want to make sure we do is make a good decision at the beginning because we really don't want to frankly pick the wrong technology and spend millions of dollars in pursuit of that, only to discover in five or ten years that it's not going to work and have to back out and spend more money to pursue the other option. So, that's why we're being very deliberate at this point. But, you know, your listeners might be surprised to learn that a regular transit bus today, a diesel bus, is expected to last 12 years at least, and it costs about $600,000. These new busses, the battery electric busses, cost at least 50% more. So, we're pushing close to $1,000,000 there. And the hydrogen busses cost a little bit more as well. Then, we have to roll in all of the facility changes that would be required, the operating changes that are there as well. And it helps us get sort of a holistic, comprehensive idea of the costs. And, yes, we do have some modeling and preliminary cost estimates about this. What we think best estimate at this point suggests that we would probably need to spend somewhere between $50 and $75 million more than we're already spending over the next, say, 20 years to fully transition the fleet to one or the other of these technologies. So, it is a considerable investment, a considerable amount of resources that would then not be available for other projects in the community. However, we're very excited about the federal government, and I know Representative Debbie Dingell and Senator Gary Peters and Stabenow have been very staunch supporters of the federal infrastructure bills and climate action investments at the federal level. And there are some very generous grants at a federal level that we might be able to tap that could offset a good deal of the investment--not all of it. We'd still have to bring some local money to the table, but we're very excited about the possibility of working with the federal government on this investment.

David Fair: And would you say some local investment would be necessary? That would be from our governmental units, which, ultimately, is taxpayer dollars. When budgets are determined, might we expect that you would be forced to put another millage issue before voters to cover the remainder?

Matt Carpenter: We do not anticipate that at this time. I want to be clear about this with you and your listeners. So, TheRide's finances are completely separate from all of our municipal partners: the City of Ann Arbor, City of Ypsilanti and Ypsilanti Township. Our budgets do not co-mingle at all. We have separate millages that come directly to this organization from the taxpayers. The millage that we were, you know, very fortunate to have approved in August actually has a capital set aside built into it exactly to help us pay for future capital investments, possibly including the zero emission bus investment. We also have some capacity here at TheRide itself for local investments, but any of that local match is going to need to come from this agency, TheRide. The state government is also usually at the table. They're very generous from MDOT in helping us win federal matches. But, at this time, we do not anticipate asking our local partners for additional contributions, and we don't anticipate asking the voters for anything in addition to what they've already blessed us with.

David Fair: So, I've taken you pretty far down the line. So, before I take you even further, let's talk about today. What is next in the process?

Matt Carpenter: So, where we are right now is finishing up this first document. And, you know, really at this point, you know, a journey of a thousand miles begins at the single step. We're at the single step point at this point. The initial research has been really helpful, and we're going to finish that document up before the end of the year. And we've already gotten a lot of great feedback from the public. People have given us comments in a couple of public meetings. So, we have a website page where people can type their thoughts in, and we've gotten some great feedback there. We're going to use that feedback and some reactions from our board to finish up that document, and then we can say, "Okay, that's done. That's the first step." And then we think we have more work to do. We have a lot of really great staff here in the organization, including our maintenance department. These are the guys who are--and girls--who are going to be fixing these vehicles, whatever they are. And I really need to hear from them what they think about this technology. So, we want to take some time and get their expertise in this. And that may mean, you know, flying them off to the places where these vehicles operate today, so they can talk to the mechanics who are really using them and get a real hands-on perspective. We need to work with our partners, the City of Ann Arbor in particular, because any modifications to our building are likely to be heavy and may require coordination with the Zoning Planning Commission or the fire department. So, we're setting up those meetings. And we need to think about with grant windows that come around about once every year and make a decision about, you know, what year we're probably going to be best prepared to win the money. And I think this is an important part is the federal government's investments here are competitive, so we need to put together a proposal that can beat every other transit agency in the country that is also going after this money. So, that means a lot of preparation, having our ducks in a row, having our budgets together, and being able to demonstrate to the federal government that we're a low-risk partner, that we would make good use of their money, and there would be a wonderful ribbon-cutting very quickly. So, a lot of prep work still to do. And, ultimately, we do have to make a decision about which one of these technologies we want to pick.

David Fair: And, finally, with all of that work that lay ahead, what is kind of best-case scenario to getting TheRide's fleet entirely zero emission?

Matt Carpenter: That's an excellent question, David. It is going to take time. This is not something that, you know, can turn on a dime. Transit busses, as I said, need to last about 12 years. And that's just a good life cycle and budgeting number. It's also what the federal government expects from their investment. So, we have 100 busses today and we replace about eight of them a year. It will take, you know, 12 years to turn over the fleet at the fastest we could go. Most likely, if we proceed a bit more cautiously, take some time at the beginning, I would guesstimate anywhere from 12 to 20 years to complete the entire transition. A lot depends on how much funding and how stable that funding can be. And we know that the Biden administration, with support from Senators Peter, Stabenow, and Representative Dingell, are very supportive of this work. And if that federal support continues consistently over that period, we may be able to accelerate it. If federal investments are disrupted, that might be a setback. So, I think once we get our plan together and ducks in a row, the actual execution will depend a lot on how much money is available.

David Fair: Well, we'll look forward to learning about all of the big decisions you have to make in a relatively short period of time. But I thank you for your time and for the information today, Matt.

Matt Carpenter: Thank you so much, David. Have a wonderful day.

David Fair: That is Matt Carpenter. He is the CEO of the Ann Arbor Area Transportation Authority, discussing the progress and challenges of ultimately making TheRide fleet entirely zero emission. For more information, visit our website at WEMU dot org. Issues of the Environment is produced in partnership with the Office of the Washtenaw County Water Resources Commissioner. And you hear it every Wednesday. I'm David Fair, and this is your community NPR station. It's 89 one WEMU FM Ypsilanti.

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