Skip to content

Recent Studies Shine Brighter Light on Battery Electric Bus Problems

By Jeffrey Clarke, NGVAmerica

If you did not dig deeper, you might not realize that battery electric buses (BEBs) are failing to live up to the hype. That is because recent reports gloss over problems or proclaim success where it doesn’t exist. NGVAmerica’s report Maximize Clean Transit Investment: Natural Gas Outperforms Electric issued in 2020 shown a bright light on the problems with electric buses: too expensive, lack of operational savings, the need to deploy larger number of buses to do the same work as other technologies, and so forth. Much of the data in that report came from the ongoing study involving Foothill Transit’s fleet, which the National Renewable Energy Laboratory has been tracking for several years now.

The Foothill studies have demonstrated that existing natural gas vehicles outperform the current generation of electric buses in virtually all key categories: operational costs, capital costs, and reliability. The electric buses have not only not been less costly to operate but they have been deployed in routes that accumulate fewer miles, which further undermines the argument that these buses are ready for prime time and that they will save transit agencies money over their lifetime. And in a real stunner, we learned last week that Foothill Transit is throwing in the towel with respect to the Proterra bus fleet that is the focus of NREL’s series of reports. Foothills’ Board voted last week to return or permanently retire the buses, which have been out of service for months due to problems including a fire and issues with in-route charging. We also learned that the transit operator plans to ask the Federal Transit Administration (FTA) to waive penalties or costs associated with early retirement and that it is suggesting the FTA or Congress consider reducing the required lifetime for electric buses. Buses funded with federal dollars currently must be capable of service for 12 or more years, but Foothill authorities apparently no longer believe that is realistic with electric buses.

In the latest NREL Foothill Transit report issued in June, we learn that the electric buses operated out of the Pomona bus garage have been parked for some time, and that natural gas buses are being used to fill-in on the previous BEB routes. We also learn that over the life of the evaluation, the natural gas buses had an average cost to operate of $0.60 per mile while the two different types of electric buses evaluated had an average cost of $0.94 and $1.01 per mile, which is really astounding since electric vehicle proponents typically claim that the cost to operate electric buses results in operational savings of 50 percent or more. In terms of availability, electric buses over the life of the evaluation were available 80 and 76 percent of the time, while the natural gas buses were available 94 percent of the time, far exceeding the industry target of 85 percent.

NREL indicates that the June report is the final report for the Pomona buses, but that it is now tracking Foothill electric and natural gas buses operated out of a garage located in Arcadia. The Arcadia buses are newer (most were built in 2017), and NREL started tracking their costs in 2020 (likely because they can’t track the Pomona buses anymore since those electric buses are out of service). For the Arcadia buses, Foothill plans to rely mostly on bus depot charging and not on route fast charging. The results so far show that the natural gas buses cost $0.06 less per mile when fuel and maintenance and repair costs are combined, with the natural gas costing $0.72 per mile and electric buses costing $0.78 per mile. The capital cost to acquire the natural gas buses was $575,000 per bus and the electric buses costs $898,854 per bus. It will be interesting to follow these buses as they currently are under warranty and the electric buses initially benefit from a 5-year preferential rate for electricity that excluded demand charges.

Several other recent transit bus evaluations are worth reviewing. These include AC Transit’s June 2021 report that does not include natural gas buses but reveals once again that savings and performance with electric buses is questionable. In that report, a key takeaway is that the electric buses had a dismal availability rate of 57 percent (i.e., were not available 43 percent of the time). Operationally they cost more than the diesel buses operated by the transit agency but were able to show a net cost savings due to the sale of low-carbon fuel credits. After including the credits, the electric buses on average cost $0.78 per mile and the diesel buses cost $0.88 per mile. Without credits, the electric buses cost $1.39 per mile to operate. Even assuming the buses are operated the same number of years and miles, if the buses are operated for 450,000 miles, they will only save AC Transit $45,000. This is not nearly sufficient to offset the added cost of the electric buses which cost $938,184 a piece compared to the $488,247 per diesel bus.

The last note here is to consider the recent “success” story touted by the San Joaquin Transit agency in this BEB report. The transit agency based in Stockton, California successfully lowered its fuel costs from $2.31 a mile to $0.68 by working with its local utility to address demand charges and institute preferential fueling rates for its electric buses. To put this in perspective, the Foothill electric buses on average have cost $0.42 to $0.45 per mile to operate when just looking at fuel costs. By comparison, Foothill’s cost of natural gas fuel has been $0.28 and $0.37 per mile.