In the last decade, electric vehicles have become mainstream. Having captured a small but growing share of the passenger-car market, and an enormous amount of media buzz thanks to Tesla, the EV industry is now setting its sights on the bus market.
Several companies that manufacture battery-electric buses, or BEBs, are selling the product to cities interested in zero-emission buses that operate without trolley wire. (While many cities already have extensive networks of electric trolleybuses, such as Zurich and San Francisco, these buses require overhead wires to operate.) Manufacturers include the longstanding Canadian bus manufacturer New Flyer, China’s BYD, and the American startup Proterra.
As part of generous government subsidies to BYD, Shenzhen has replaced its entire fleet with BEBs. Cities in Europe and the United States are also experimenting with them. Moscow plans on replacing its trolleybuses with BEBs, and small and medium-sized American transit agencies have begun leasing or buying this technology. Part of the rationale behind this shift is to reduce local-diesel bus pollution; part of it is about cutting greenhouse-gas emissions, and part is the perception that BEBs are a futuristic technology.
But is the technology really ready?
There are reasons for skepticism. So far, it looks like BEBs struggle when it’s too cold (below freezing) or too hot, and on routes with hills. The global frontier of public-transit innovation in Western Europe is cautious about adopting BEBs and prefers a hybrid form of trolleybuses and battery-electric technology called in-motion charging, or IMC. Some Swiss cities are adding trolley wire at low cost while using IMC to extend the range of their existing trolleybuses several miles beyond the wire.
Range anxiety, but for buses
Battery-electric vehicles’ biggest problem has always been range. At the dawn of the automobile age, electric cars competed with gasoline and steam-engined vehicles: In 1900, 38 percent of U.S. cars were battery-powered, and only 22 percent boasted internal combustion engines. As late as the 1910s, Thomas Edison was working on an electric car and a network of charging stations. But in time, gasoline-fueled cars came to dominate the market, partly because a car’s range on a full tank of gas was far greater than on a full battery charge.
Dramatic improvements to battery technology have fed the recent EV renaissance, allowing such models as the Tesla Model 3 and BYD Qin to travel about 200 miles on one charge. That’s helped alleviate the “range anxiety” that keeps many U.S. drivers from considering an electric vehicle.
Still, the energy density of batteries remains well below that of gas. And, unlike most passenger cars, city buses run for the entire day. The big American transit agencies run buses for about 25,000 to 40,000 miles a year, which is two to three times the average distance a car is driven—and buses have a more energy-intensive urban driving cycle (with little highway running), totaling 100 to 200 miles of city running per weekday.
Moreover, the routes most likely to get battery-electric technology are the strongest ones, where fleet utilization is higher, since electric buses are more expensive to buy than diesel buses. This pushes up the required range for operating without midday charging.
On heavy-duty buses, the range has not been enough. Albuquerque provides one example: It found its BYD buses’ range to be only 177 miles on one charge, compared with a contractual promise of 275, and this was not enough to run a full day’s service. In Vancouver, a BEB trial talks up rapid recharging during layovers—there is no expectation of being able to run a bus for an entire day without recharging. Rapid recharging is labor-intensive, since a worker must supervise it, unlike recharging or refueling at the end of the day.
An electric bus produced by China’s BYD is parked at the announcement of the opening of an electric-bus manufacturing plant in Lancaster, California, in 2013.
In Moscow, Mayor Sergey Sobyanin has made a big push for BEBs, which in his view are more modern than the city’s expansive trolleybus network. The city recently purchased 100 buses each from two Russian automakers, Kamaz and Gaz. The London-based transit advocate Martin Wright compared Moscow’s procurement and operating costs and talked to Russian observers. Wright said (as of early fall) that Moscow’s trial routes for BEBs—trolleybus Routes 73, 76, 80, and 83—have had to use more buses just to run the same service, pointing to before and after slides. The four routes appear to have gone from 46 trolleybuses to 82 BEBs without any increase in service frequency, presumably because BEBs have considerable down time for midday charging.
