The Rocky Road to Bus Electrification
While electric vehicles are becoming much more commonplace, transit agencies have had mixed experiences with electric buses. Many are still exploring how best to reduce fleet emissions.
Early last year, the Denver Regional Transportation District (RTD) placed an order for 17 new battery-electric buses, part of a bigger push to replace its bus fleet with low-emissions vehicles and help advance Colorado’s ambitious climate goals. But earlier this spring, RTD, which runs the area’s public transit service, canceled the order.
While the agency is still committed to replacing its bus fleet with zero-emissions vehicles, a spokesperson said, an “extensive assessment determined current facilities could not support the latest low/no-emission propulsion technologies.” In other words, RTD doesn’t have the right infrastructure to store and charge the latest battery-electric buses.
And Denver isn’t alone. Even with advances in electric vehicle technology and new federal support for electric buses, many public transit agencies are finding it difficult to transition their fleets at a major scale. The reasons why range from a lack of infrastructure to concerns about cost, reliability and range. Meanwhile, zero-emission vehicle technology continues to evolve, leaving open questions about which types of buses can best serve transit agencies’ service, climate and budgetary goals.
In Denver, some RTD board members expressed “embarrassment” for canceling the contract, according to a report in The Denver Post. But the agency is still pursuing a carbon-reduction strategy. A spokesperson said that RTD “has a plan to look holistically at technology and resources needed to transition facilities to accommodate [the] latest low/no-emission vehicles.” That includes facilities as well as personnel, the spokesperson said. The plan should be complete by the end of 2024, she said, and the agency doesn’t have its next major bus purchase scheduled until 2026, she added.
“Rather than continuing down a narrow path that limits RTD to one type of battery-electric technology, canceling the contract ensures RTD can plan for the future with a holistic strategy for its facilities and fleet,” she said in an email.
Public Transit Benefits Climate, Electrified or Not
Many agencies want to move aggressively to reduce greenhouse gas emissions, but may have good reasons to take bus electrification slowly, says Christof Spieler, a vice president and director of planning at the consulting firm Huitt-Zollars and a lecturer on transportation at Rice University. Spieler recently wrote a piece for TransitCenter, the New York-based advocacy group, arguing that electric buses will help promote climate goals, but that agencies are “right to be cautious” as they seek to electrify.
Many agencies don’t have the infrastructure in place to store, charge and repair large numbers of electric buses, and there are also questions about whether local utilities are prepared to supply all the power agencies need to keep buses charged. Other obstacles include the reliability of new models of buses and the relevant expertise of maintenance workers, along with scheduling challenges that may arise when buses need lots of time to charge.
“Some of [these issues] have been known for a long time and some of them are things that agencies are finding out as they’re piloting new buses,” Spieler tells Governing.
Agencies have different experiences with electrification based on a variety of factors, including how committed leaders are to adopting zero-emission vehicles, how knowledgeable their workforce is, the topography of their cities, and the availability of funding and incentives. And while electrification is good for the environment, Spieler says, agencies shouldn’t prioritize it over running fast and reliable service — because getting people onto transit is a more effective climate strategy than running lower-emission buses.
“The difference between whether somebody is in a car or a bus is a huge environmental factor we should be talking about,” he says. “If we do electrification instead of growing service or ridership, then we’re actually making the planet worse off.”
Agencies are testing out new bus models. Since 2018, Dallas Area Rapid Transit (DART) has been using seven short-range electric buses it bought from the manufacturer Proterra. Those buses, which DART uses on a single route, go about 30 miles apiece before needing a charge, according to the agency. Earlier this spring, DART also put its first long-range battery-electric bus into service. The bus, another Proterra model, has a range of about 300 miles. DART was able to get a grant to buy its first batch of short-range buses, and used some leftover money from the same grant to buy the longer-range model, says Darryl Spencer, the agency’s vice president of engineering and construction.
“We wanted to continue to experiment with battery-electric buses,” Spencer says. “We want to really learn its behavior and learn its capacity, learn the range.”
While Texas is not a state that puts pressure on its transit agencies to decarbonize, DART is hoping to keep pushing forward with electrification — slowly. It recently put out a solicitation for five more long-range electric buses. But it has no current plans to build a dedicated bus depot for electric vehicles. So it will be limited in how much electrification it can do by how well it can retrofit existing facilities for charging.
“Infrastructure, costs and range are the factors and the challenges ahead of us on deploying more electric vehicles," Spencer says.
Other agencies have had headline-grabbing snafus, like battery fires and recalls that have delayed electrification. The Southeastern Pennsylvania Transportation Authority (SEPTA) bought 25 Proterra electric buses in 2016, but soon had to sideline them because of cracked chassis and other maintenance issues. For several years, SEPTA has been involved in legal discussions with Proterra, which haven’t been resolved yet. But Emily Yates, SEPTA’s chief innovation officer, says both parties are working to get the buses back in service.
In the meantime, SEPTA hasn’t bought any additional battery-electric buses. That’s partly because of its first experience — “Once bitten, twice shy,” Yates says — but also because the zero-emission technology keeps evolving. Agencies like SEPTA want to be on the vanguard of technology that makes their service cleaner, more pleasant and less carbon-intensive, but there are benefits to waiting for innovations to mature.
“Some of the challenges that we’re experiencing today might not be a challenge in three years,” Yates says. “Some of the challenges are space to properly and safely charge buses. The batteries right now are huge, so space is a challenge. But now that it’s out on the market that is a challenge with transportation authorities in general, will that … drive the innovation of more spatially effective batteries?”
While SEPTA sorts out the issues with its first fleet of battery-electric buses, it’s finishing a full transition to hybrid diesel buses. And in February, it approved the purchase of 10 hydrogen fuel-cell buses. Those vehicles are quieter and cheaper to maintain than traditional diesel buses, the agency says, with much lower greenhouse gas emissions. But they come with their own challenges, too, Yates says, like securing a reliable supply of hydrogen in a way that doesn’t cancel out the emissions saved by the vehicles themselves.
While SEPTA and many other agencies have committed to reducing their emissions, they’re all watching each other to see what strategies to imitate and what to avoid.
“We’re all kind of trying to figure out what the next step is,” Yates says.