Why the Solution is Propane and Electric for Bus Fleets

June 2, 2024

INDIANAPOLIS – A Sunday Green Bus Summit session invited districts with propane and electric school buses to compare the two and share how they are both being used to meet emissions goals.

David Walters, director of autogas business development for session sponsor the Propane Education & Research Council (PERC), reviewed the cost and emissions savings that propane has brought districts but noted that many of today’s mandates require zero-emissions vehicles, which means electric school buses (ESBs).

Stephen Whaley, formerly of PERC and now eastern alternative fuels manager for Blue Bird, compared propane implementation with the more expensive electric implementation. He noted that both were significant aids on the path to zero emissions.

“The energy has to come from somewhere,” he said, adding that the carbon intensity – the measurement of the total amount of carbon emitted per unit of energy consumed by different fuels – for propane is 79 compared to electric’s 130.

Propane has the added advantage of being plentiful in the U.S., familiar, easily scalable, and reliable in cold weather.

Transportation Director John Thomas said Eastern Carver Country Schools in Minnesota started its propane journey in 2009 over frustration with diesel prices and currently has 92 propane buses out of its fleet of 140. The first electric bus joined the fleet four years ago through grants from the VW Mitigation Fund and the American Lung Association.

Meanwhile, Director of Transportation Brooks McQuinn from Malone Central School District in upstate New York shared that half of the district’s 44-bus fleet is propane with the recent addition of four electric school buses. New York requires only electric school bus purchases starting in 2027, which McQuinn said U.S. Environmental Protection Agency grants are assisting with.

Fueling. McQuinn shared that propane dispenses similar to diesel, while ESBs take eight hours to charge on a level 2 charger in the middle of the day, with one charge costing about $30. Thomas agreed and added that overnight charging is cheaper, but the district’s partner utility helps keep the rate low overall.

Terrain. Propane buses take on hilly terrain better than diesel buses, and ESBs return to the transportation facility with a higher charge due to regenerative braking on the downhill ride, McQuinn said. “Driver training is a huge factor in this,” Thomas pointed out.

Staff Training. McQuinn said his mechanics saw little difference between propane and diesel bus maintenance, while ESB maintenance is handled by Cummins. Thomas said his early propane adoption gave mechanics a learning curve and time to get over their fears, but they are comfortable now and must perform less maintenance than on diesel buses due to no DEF.

Funding. Thomas said his diesel buses are too new to make use of most federal EV grants and there are challenges with space for charging infrastructure. But he confirmed he thinks EVs are the future. McQuinn likewise confirmed he is capped on charging infrastructure so he is looking at reconstructing the parking lot and is seeking space across the street.

Mandates. McQuinn shared he is buying propane and diesel until the 2027 EV mandate deadline. Walters noted that eight states that adopted the California Air Resources Board’s Advanced Clean Truck regulations have mandates on EV purchases, but those governors have “expiration dates” and policies may change, so districts should stay informed. Whaley mentioned that some forward-thinking fleets are using drop-in fuels that can be easily swapped out.

The Future. McQuinn said propane is his first choice but ESBs are growing on him. Thomas agreed and noted the need to be versatile and get ahead of EV mandates. McQuinn said he sees the New York mandates being pushed back as infrastructure isn’t adequate and bus demand isn’t being met. Whaley weighed in from the OEM perspective, saying that market demand and supply chains drive bus production. Blue Bird starts with the same type of chassis and builds in different fuel options, he confirmed.