Two newly released industry case studies and other evidence around the country are powering arguments in favor of alternative fuels’ ability to reduce costs and improve performance while easing environmental impacts.
A case study by Blue Bird and ROUSH CleanTech demonstrates Student Transportation, Inc.’s switch to 435 propane autogas buses to serve the Omaha and Millard (Neb.) Public Schools districts resulted in “saving almost 50 percent per gallon on fuel costs compared to diesel” in a single year. Additionally, these buses are expected to emit 42.6 million fewer pounds of carbon dioxide over the fleet’s lifetime.
A case study by the Propane Education & Research Council (PERC) indicates the Indian River County School District in Vero Beach, Fla., “realized a (return on investment) on its propane autogas school buses within eight months after deployment.”
Several transportation directors with decades of experience reinforce those findings, touting the operational, environmental and financial advantages they’re tallying with various alternative fuels.
“There’s just too much of this stuff that’s been perfected to ignore it,” said Ralph Knight, transportation director at Napa Valley (Calif.) Unified School District and co-chair of this month’s STN EXPO. “Change is uncomfortable but there’s a lot of us out here proving it can work.
“Why not jump on the bandwagon and save yourself some money?”
‘LESS COMPLEX, MORE ADVANCED’
The Omaha case study focuses on the Metropolitan Omaha Education Consortium’s push to “reduce costs and the carbon footprint” of its school fleet and its work with STI, North America’s third-largest provider of school-bus services, to shift to alternative fuel sources.
STI ordered the 435 Blue Bird Vision buses for integration into the Omaha area fleet for the 2013-14 school year. Its drivers received operational training from ROUSH CleanTech and gained a quick appreciation for the vehicles’ “quick start-up, quiet engine and smooth ride.”
“Although drivers are trained to accelerate slowly to optimize fuel efficiently, many drivers are impressed by the ‘get up and go’ that these propane autogas buses deliver,” according to the study. It quotes veteran STI driver Willie Campbell: “These buses have more pick-up than our diesel buses. You can quickly get through an intersection or across a railroad after being stopped.”
The quicker start-up characteristics of propane are noteworthy in Omaha, where winter lows average in the teens and highs barely top freezing. “STI’s diesels are started the night before, but STI doesn’t need a ‘start up crew’ to warm the propane autogas buses. This fact alone saves the school district more than $1,000 each cold weather day. Crews report that buses start up without issue and quickly produce heat,” the case study states.
STI also has been able to reduce maintenance costs. “The design of the chassis and engine allows for more engine bay access for maintenance crews to perform routine upkeep. Regular filter and oil changes are less expensive compared to diesel, and propane autogas doesn’t require diesel exhaust filters. School buses fueled by propane autogas use about one-third the amount of oil when compared to a diesel bus,” the study notes.
STI Omaha Shop Manager Brian Urwin indicated the cost of interval maintenance parts is approximately $25 for propane autogas buses compared to $90 for their diesel counterparts.
“Propane autogas maintenance is cheaper and simpler to handle. These systems are less complex mechanically than diesel but more advanced technologically,” Urwin said.
During the study period, propane autogas averaged $1.75 per gallon while the diesel that fueled the remaining 20 buses averaged $3.60 per gallon. Despite the fuel economy of diesel over propane by several miles per gallon, that price disparity was significant enough to save the district nearly $5,000 per day as the propane autogas buses traveled more than 3 million miles over the course of a year. The alternative-fuel vehicles also generated an estimated 4.2 million fewer pounds of carbon dioxide per year.
STI operates 12,000 vehicles to serve 165 school districts across the nation, and more than 10 percent are fueled by propane autogas.
“Now, STI is working on maximizing fuel usage through collaboration with ROUSH CleanTech to develop integrated ‘Fuel-savings’ training,” the study concludes. “With 96 percent of its school buses running on propane autogas, Omaha is projected to become the first school system with a 100-percent propane autogas bus fleet.”
‘GO GREEN & SAVE GREEN’
The PERC study, titled “Florida School District Goes Green, Saves Green with Propane Autogas,” noted the Indian River County District began researching alternative fuels in 2009 to respond to the economic recession and comply with new U.S. Environmental Protection Agency (EPA) and California Air Resources Board (CARB) emissions standards.
The district, which transports approximately 9,550 students twice each day, was the first in Florida to “adopt the new liquid injection propane autogas school buses.” Officials purchased three Blue Bird Vision Type C propane autogas buses to test them on the district’s intercity, mid-range and long-distance routes.
Satisfied with the results, the district was committed to replacing older diesel buses with more Blue Bird Visions equipped with ROUSH CleanTech fuel systems and Ford 6.8-liter engines. However, officials were concerned that deep budget cutbacks would prevent the district from making the transition if the move to alternative fuels required steep start-up costs.
“Fortunately,” said George Millar, Indian River’s director of transportation, “propane autogas was both inexpensive and environmentally friendly.”
The study states that the propane autogas- powered buses “emit 40 percent fewer smog-forming hydrocarbon emissions than gasoline and 80 percent fewer than older diesel engines.”
“Propane autogas runs so clean that I can swipe my fingers around the edge of a tailpipe on a bus we’ve been running and there will be absolutely no soot residue on my hand, not even after extreme usage and many miles on the road,” according to Millar.
Total costs were also a crucial consideration in the Indian River County district’s move; minimal modifications to its existing facilities were a plus when weighed against CNG fueling station costs of $1 million or more. Indian River currently operates a 1,600-gallon capacity propane tank and one-hose dispenser but is weighing an upgrade to an 18,000-gallon storage tank with two double-hose dispensers to serve its expanding fleet.
The study notes: “On-site propane autogas infrastructure is compact and easy to install, and only requires a large propane tank and no-spill low emission dispenser. Indian River worked with its local propane retailer to identify the best infrastructure for the fleet and agreed to a slight mark-up on fuel cost in order to cover installation and maintenance. The district also opted to install a fuel management system in order to receive an accurate record of their fuel data and for added security.
“Overall, the district reports seeing ROI within eight months of use and saving $4,800 a year per bus on fuel costs with propane autogas when compared with conventional diesel.”
Added Millar, “Our overall mpg with propane is about 3.6, but even with a lower fuel economy, we’re still saving money due to the low cost of propane autogas. Cost per mile, we’re ahead of the game.”
The propane-powered buses’ design and engineering also factor into the maintenance equation in a district where approximately 45 percent of routes run on gravel or dirt. Millar indicated rear-engine vehicles, including all CNG buses, tend to experience more clogged filters when traveling on dirt roads, while front-engine propane buses do not.
‘LITTLE TO NO WEAR’
Knight, who oversees one of the nation’s leading hybrid/electric school bus fleets, has enthusiastically experimented with new technology since the district purchased two electric buses in 1995.The Napa Valley fleet consists of 42 CNG vehicles, five electric buses currently that are out of service, six propane special needs vehicles, 11 older diesels, six clean-diesel Collins, six Thomas C2e hybrids, one IC Plug-In hybrid and three Collins/Ford/ Azure hybrids. The clean diesels and C2e’s operate on bio-fuel.
When diesel supplies were tight and prices soared, fuel for the district’s 37 natural gas buses remained plentiful. However, hybrid vehicles do require drivers to rethink their habits because “the miles-per-gallon is really in their hands,” Knight said.
“If you want the most miles out of a charge, you have to learn to drive that vehicle. It doesn’t mean you have to be a ‘grandma’ driver, but if the driver is full throttle and full brake you’re not going to get the MPGs,” Knight said.
Individual alternative-fuel vehicles are rolling up 350,000 miles or more for the Napa Valley district and are requiring just one oil change per year.
“We’re being told we can go 50,000 miles, but that’s two years for us and I just can’t do that,” Knight said. “We dump all the CNGs every summer and the oil is as clean as when it went in there. We’re seeing the same thing with propane. With diesel, it runs 10 miles and it comes out gooey black. You’re talking a lot of money there.” Knight, who has secured $12 million in grants for alternative- fuel vehicles, encourages other transportation directors to seek such funding, including money from companies that support new technology.
A GOOD BALANCE
Mark Swackhamer, senior manager of fleet operations for Houston ISD, the largest district in Texas and seventh largest in the nation, has added 91 propane buses in the past three years to his 1,060-bus fleet that also includes 160 green diesel buses.
“It’s good to have a balance,” Swackhamer said.
Each propane bus saves the district an average of $3,000 in fuel costs per year, depending on federal tax incentives. Those incentives expired at the start of the year, but Swackhamer said he believes the odds are “pretty strong that they’ll come back.”
“They’ve gone away in the past and come all the way back retroactively,” he added.
Additionally, the district’s use of biodiesel offsets 105,000 gallons of petroleum each year.
“It’s cost neutral, invisible to the user and greener,” Swackhamer said.
He said he has given consideration to hybrid and CNG vehicles but isn’t prepared to take either step yet. He said he favors propane as of now because it is “cost effective and has good availability, the fueling time is as quick and easy as diesel, and the fueling infrastructure is cheaper.”
Meanwhile, Ron Latko, the recently retired Mesa (Ariz.) Public Schools director of transportation, said an ongoing challenge with diesel vehicles will be in keeping pace with emissions standards. Regulatory changes since 2007 have forced more engine modifications and higher costs — and they aren’t over yet. So far 90 of Mesa’s 544 buses are powered by propane.
“We have to keep adding and adding and adding things. At a certain point, you’re making the engine work harder,” he said. “What are we going to do, supercharge the supercharger? This whole process is much more complicated and increases the vehicle’s cost. I don’t know what’s next, but the EPA is not going to give up, and more regulations are coming.”
Latko said diesel buses also have a shorter lifecycle in the district — 13 years compared to 18 for propane — and the cost to change out an engine is about four times greater. Routine maintenance averages $0.03 per mile for diesel buses and $0.015 cents per mile for propane.
“We deal with excessive heat, but we don’t have any problems with propane, and we don’t have to do emissions testing,” he said. “How much is that worth to you? It’s a normal, run-ofthe- mill thing you have to do during the course of the year, but it still costs you.”
Districts that might have issues with gas or diesel pilferage are less likely to face similar issues with propane. “There are a lot of gas and diesel cars and trucks running around,” Latko continued, “but not very many propane.”
