Neosho Schools Propane Case Study

By adding propane buses to its fleet, Neosho School District has noted savings on fuel and maintenance. On average, propane autogas costs up to 50 percent less than diesel. As part of its negotiated contract, Neosho pays a locked-in rate of $1.39 per gallon of propane. By comparison, the district pays $2.01 per gallon for diesel, although it has been closer to $3 over the past few years. In addition, the district capitalizes on federal tax credits of 50 cents per gallon.

The district runs about 185,000 miles with its propane buses. Looking at the average of diesel costs from the previous four years, savings totaled $29,077 annually for the 18 propane buses. For the 2017-2018 school year, Embrey estimates fuel savings, along with the alternative fuel tax credit, brought total savings to $34,000 for the 18 propane buses. “Any savings from alternative fuel buses helps our transportation department serve as better stewards of the district’s money,” Embrey said.

With propane autogas, no exhaust after-treatment or diesel emissions fluids are required like with diesel to meet today’s strict emissions regulations. Propane vehicles don’t need particulate trap systems, turbochargers and intercoolers. Plus, propane uses less engine oil. For example, an oil change for a Blue Bird Vision Propane school bus uses seven quarts, compared with over 17 quarts for a typical diesel engine. The district reports that service time and costs for oil and filter changes for each propane bus were approximately 50 percent less than for diesel. The district has decreased its oil and paid less for filter packages. After finalizing one school year of cost data for its 18 propane buses, the district found its air filter savings totaled $1,350, fuel filter savings were $540 and DEF fuel savings came to $931. Plus, the district paid $630 less for each of its oil changes.

“The mechanics especially like the location of the propane engine as they can easily work within the space. Plus it takes them a lot less time to do each service,” Embrey said. The district mechanics have noticed a longer wait time to obtain propane bus parts than for diesel buses.

More saving shows up for the district in the winter. Due to the chemical properties of propane autogas, the propane buses warm up faster and have no cold start issues. Unlike diesel vehicles, these buses can start up in temperatures as low as -40 degrees Fahrenheit. The district’s electric bill is significantly lower because the propane buses don’t rely on block heaters. Improvements Inside and Outside

The quiet operation of propane buses has benefited both drivers and passengers. “It took a while for students to realize they didn’t have to talk so loud when they were in the propane buses,” Embrey said. “When drivers can hear student conversations in the back of the bus, it adds to safety and comfort.”

A warm cab is another comfort for drivers, and the improved atmosphere extends outside the bus. When the district’s buses are parked nose to tail at student pick-up time, exhaust fumes can fill the air around and even inside buses. Unlike diesel buses, propane vehicles emit virtually no particulate matter and far less nitrogen oxides (NOx). Buses fueled by propane also emit fewer greenhouse gases and total hydrocarbon emissions when compared to diesel buses.

“The propane buses allow us to greatly reduce our idle time with the buses as well as reduce the amount of diesel emissions we had within our district,” Embrey said. The district’s mechanics also appreciate the lack of harmful fumes in the service garage.

In terms of environmental impact, the propane buses emit 571 fewer pounds of particulate matter and 13,600 fewer pounds of NOx annually compared to the diesel models they replaced.