A growing number of agencies are purchasing zero-emission buses, primarily involving batteries as the energy storage of choice. As with any procurement choice, the reasons for the growing trend vary by city, but the primary rationale has been a political commitment to the cleanest propulsion possible. As with any new breakthroughs, careful attention will need to be paid to how such new propulsion affects the entire operation.

Batteries follow other electronic, digital trends
The advances in zero-emission buses have been a rapidly moving target in recent years. Take operating range as but one example. Today, manufacturers are boasting ranges of more than 300 miles on a single charge. Another example is battery life before they need to be retired. Thanks to advances in battery chemistries, some bus builders are now claiming their batteries will last as long as the full design-life of a heavy-duty transit bus, which is mandated to be 12 years in the U.S.

Of course, some of these claims come with significant caveats. Duty cycle is one; climate and passenger-load factors are two others. Buses operating in extreme climates or with steep hills, and/or with heavy heating and air-conditioning demands, as well other onboard electronic features that can gobble juice voraciously, and with heavy passenger demands, can affect both range and battery life dramatically.

That said, a growing number of agencies are all-in on these buses, committing to a conversion of their entire bus fleets within a few short decades. The most dramatic of these is in Los Angeles, where Metro has committed to conversion of its entire 2,400-bus fleet by 2030. The sheer size of this commitment, with the orders that it will produce over the next 12 years, will have a major impact on the U.S. transit bus market.

Meanwhile, just as the costs of battery-electric buses have come down, several other technologies have been getting much better. For example, the cost, range, and reliability of buses powered by hydrogen fuel cells has been improving as well, though, not as rapidly because the volumes ordered to date have not been produced and operated at the levels as their battery-electric counterparts. Yet another technology that shows great promise is the development of natural gas engines designed to use so-called “renewable” natural gas; that is, gas recovered from landfills and other sources where it is a byproduct of some other activity. Some analyses, on a comprehensive “wells to wheels” basis have the benefits far outweighing costs, including monetized environmental ones.

Is this another game-changer?
These developments make for complicated decision-making. How best to transition to a new era will have profound implications for route planning, operations, maintenance facility design, training, and a long list of other considerations. For those who marvel at how much change has taken place in public transportation in the past two decades, buckle up. The pace is quickening — rapidly.