Chances are that Muni passengers over the last 18 months have ridden on a 40-foot battery-electric bus in San Francisco on routes such as the 9-San Bruno or 44-O’Shaughnessy. The buses under test have featured sliding doors and a unique livery – like a massive lightning bolt – on the outside of the bus.
The battery-powered buses are part of a plan by the San Francisco Municipal Transportation Agency to eventually have Muni buses be emissions-free by 2040, a state-mandated requirement by the Clean Air Resources Board.
The agency intends on purchasing more battery-powered buses from select manufacturers to continue testing the technology following an evaluation report released by the agency as part of its Battery-Electric Bus Program, which initially included piloting buses from four bus manufacturers in 2022: New Flyer, BYD Auto, Proterra and Nova Bus.
Julie Kirschbaum, director of transit for the SFMTA, said emissions from Muni’s fleet currently makes up less than 1 percent of greenhouse gases emitted in the city’s transportation sector:
“The SFMTA already operates the greenest fleet of any North American city, and we are committed to continue to be even greener.”
The results of the evaluation, shared with the SFMTA Board of Directors on Tuesday, showed that New Flyer buses outperformed those from other manufacturers, including performance, procurement, and ease of inspection and issue diagnosis.
Overall, New Flyer received 371 points out of 519 points, followed by Nova with 281 points, though their overall was out of 497 points due to limited data. BYD Auto scored 261 points, followed by Proterra with 244 of 519 points.
Harley Miller, who is part of the group at the SFMTA responsible for the delivery and procuring of the pilot buses, said the agency took a holistic approach in testing the buses:
“We didn’t want to just focus on one area of the bus performance. We put these buses into real revenue service, carrying passengers, and tried to get them out into our streets as much as we possibly could.”
All of the pilot buses did meet the technical requirements and specifications, including the buses being able to travel at least 160 miles a day or more on a single charge allowing the SFMTA to use the bus for an entire day of revenue service, Miller said. The buses were able to carry passengers on any street grade just like any other 40-foot Muni bus.
New Flyer and Nova had more experience working with larger transit agencies and manufacturing buses in North America, which is reason why they scored higher, he added:
“We found that they just had a better combination of manufacturing experience and expertise, but they also focused more on customer experience, which led to them scoring higher.”
Overall, the reliability of the buses did not meet the expectations of the agency due to first-generation “technology bugs.” Miller said battery electric bus propulsion technology is fairly new in buses from North America, and added he believes the manufacturers will improve the technology by the time SFMTA needs to put more buses into service.
The report recommended not to purchase future buses from Proterra, as the company declared bankruptcy during the pilot evaluation and is under new ownership with an unclear future. Miller said Nova is also no longer in consideration, as the manufacturer announced plans to exit the U.S. market.
BYD had “significant bus quality issues” with the SFMTA having to return the buses to get fixed before they could go back into service. Miller added that BYD, headquartered in China, would not qualify for federally-funded procurement.
The SFMTA plans to purchase 18 more electric buses, including four 40-foot and three 60-foot buses from New Flyer. Additionally, the agency will purchase five buses from Gillig, a bus manufacturer based in Livermore, and buses from Solaris, a European company that plans to expand to the U.S., Kirschbaum said.
She added that the agency continues to invest in trolley buses:
“We are excited to see the trolley vehicles of today become more flexible as we prepare for the trolley vehicles of tomorrow.”
The agency is testing in-motion charging on several trolley buses where the buses can go off-wire for several miles with a charged battery. Kirschbaum said they are finding that buses can go off-wire between four to six miles before having to return to the overhead wires to recharge.
Transit officials are looking at the potential of expanding trolley routes using in-motion charging as a way to avoid a costly expansion of the overhead wire system.
Upgrading aging SFMTA facilities to accommodate battery electric buses will be costly and complex to minimize operational cost and service disruptions, the report said. Each bus yard will need to have more power to charge the buses which will require utility upgrades.
The report did not specify a cost for upgrading the Muni bus yards but said installing the electric charging equipment is just a piece of the puzzle. Many of the agency’ s bus yards are old and need other structural improvements, including seismic upgrades.
Given the complexity of upgrading the bus yards with charging infrastructure and bus yard upgrades, the report said the SFMTA will need to purchase hybrid buses in small quantities for the “foreseeable future” and purchasing trolleybuses.
That point was made Tuesday, as directors approved a $118 million contract with New Flyer for 94 40-foot hybrid buses to replace older ones.
After this purchase, Kirschbaum told directors that they would need to request exemptions from CARB on these types of purchases at least through the end of this decade due to the technology and facility restraints with battery electric buses and added that other transit agencies will most likely also need to request exemptions.
The public can read the battery electric bus evaluation report online.
