Looking to the Future
to Solve Today’s Problems

Companies are thinking completely out of the box
to solve the industry’s current fuel and emission problems

By Stephane Babcock

For the past few years the school bus industry has been slowly easing into the use of alternative fuels. But now, with diesel prices rising by leaps and bounds and recent and impending mandatory emissions reduction standards, school districts are looking to jump in with both feet and embrace technology that until just recently seemed out of reach.

The School Bus of Tomorrow
While building a transit bus for the Federal Transit Administration (FTA), Dale Hill got a late night idea that has transformed into a school bus that could potentially emit zero emissions, would cost about $750 a year to run 10,000 to 12,000 miles and might eliminate certain incremental costs, such as oil changes.

In 2004, the FTA approached Hill and his company, Proterra, to reassemble a design team that in 1997 had built a fleet of 36 hybrid-electric buses for the Denver Regional Transportation District, which use a four-cylinder Ford engine fueled by natural gas that runs a generator to charge the batteries. Taking grants from FTA, the California Air Resources Board and the Department of Defense, Hill and his team designed a transit bus that is battery-dominant with a cavity in the rear for an auxiliary power unit to replenish the batteries, which could include a fuel cell, a diesel generator or a CNG generator.

“I woke up in the middle of the night and I said, ‘This bus will go 50-70 miles on just battery, and a school bus drives 25-40 miles and then it sits all day,’” recalled Hill. “So we took our basic design and designed an all-electric school bus.”

The result is a school bus that has zero emissions and only costs $0.05/kwh for nighttime charging, which equates to paying about $0.35 a gallon for diesel instead of $5 or more. But it also has power to go along with economy. It can pull an extended amount of weight, according to Hill, who hooked it up to a 10,000-pound forklift that “almost didn’t phase it.” With an average school bus running 10,000 to 12,000 miles a year and using $8,000 to $9,000 of fuel a year, the $750 annual cost of running the Proterra bus seems implausible albeit intriguing.

“This is some really exciting technology,” said Marc Horner, fleet manager for Jefferson County Public Schools, in Golden, Colo., located just minutes from Proterra’s manufacturing facility. “There’s no magic bullet in alternative fuels. The global fuel situation is such a complex problem. Here, you have a bunch of people trying to do the right thing for the right reason.”

Horner’s department donated a junk bus to the Proterra team for a crash test to show a comparative analysis of Proterra's composite body and a normal school bus body. To construct the body, multiple layers of fiberglass, epoxy and netting are combined, with the wheel wells strengthened with carbon fiber. The composite body, which comes in two pieces, was tested by using 4,000-pound car traveling at 25 miles an hour and hitting the bus at its midpoint.

“It only scratched the paint,” said Hill. “The composite also does not corrode due to salt or magna chloride on the roads.”

The cost of the first 10 buses will be higher than most districts are used to spending on a school bus, but Hill is aiming at dropping the initial $300,000 price tag to $200,000 as soon as possible, a price similar to that of IC Bus’ hybrid. He has also set up a 12-year leasing plan that would allow districts to finance the purchase over the life of the bus.

“We have $200 million of lease finance money available on 12-year terms with no money down and no payment in the first year. It allows them to pay the incremental costs of the bus out of their fuel savings,” said Hill, who added more than one transportation director has already put their name down for one of the first 10 to be produced.

“An all-electric school bus would work out great with us in that we run in the morning and in the afternoon, so we could plug-in midday,” said Horner. “Also, it’s mutually collaborative in that we are located near Proterra, and we could help by providing a lot of research and development data.”

The Hybrid Retrofit
Like Dale Hill, when Rob Lykins started working on a hybrid school bus retrofit, he first approached his hometown school district with the idea. Now, almost two years later, Lykins, owner and president of Productive Concepts Inc. (PCI), not only has the support of the Randolph Eastern School Corporation in Union City, Ind., but also the state school bus committee.

“When you first start approaching people, it’s like you're speaking a different language,” said Lykins about his past and current discussions concerning his hybrid system, which acts as a retrofit to a 2004 model year or newer bus. ”We believe we can cover about 80 percent of school buses out there that have front engines.”

The system is currently on one Union City school bus, which was installed in December 2007 and received final approval from the DOE this past January.

“We are very excited to be the beta system for this great project,” said Cathy Stephen, superintendent of Randolph Eastern School Corporation. “It is good for the environment, the health of our students, and it is good for the school and local economy.”

Lykins’ hybrid went through all the standard durability testing, and the Indiana State Police also wrote new inspection criteria. This includes making sure the ground circuit interrupters are working properly, everything is mounted to the proper flanges on the frame rails and other system-related specs.

“We are primarily confirming our fuel savings. We’ve put it out there that we’ll save between 25 and 35 percent on fuel, and we want to confirm those numbers and see exactly where we’re at. We had the bus in service for about three months and tried to circulate it through almost every route our school district runs. We have some preliminary data, and now we are just doing the final confirmation of those numbers,” said Lykins.

Once the figures have been confirmed, PCI will be ready to start a full production run of the system, which, unlike other hybrid-electrics, does not need to be plugged in. On initial startup the diesel will idle for between 30 seconds and a minute and a half (depending on the leftover charge) to get the initial power boost required to fill the ultra-capacitors. From there, the system uses regenerative braking — anytime the driver lets off the gas to slow down or steps on the brake, that kinetic energy is captured and transferred back through the system and stored as electricity in the ultra-capacitors.

“We’re expecting to convert several buses in the state of Indiana itself,” said Lykins. “We’ve started the process of setting up conversion centers in other states. But, first, we need to go to each department of education and go through a similar process to the one we went through in Indiana.”

The initial cost of $35,000 to $40,000 for the system and complete installation does not seem excessive to Randolph Eastern's Stephen when put in the grand scheme of the current state of the economy.

“When costs are high for everything, our families need for us to provide more transportation, not less. And they certainly cannot afford to pay for transportation services,” she said.

A Different Type of Hybrid
In 1983, Portland, Ore., Public Schools experimented with the use of alternative fuels by converting three school buses to run on propane. Fast forward 25 years later and 84 percent of the district-owned buses and 88 percent of the contractor-owned buses now operate on the alternative fuel.

“We pretty much run on dedicated propane, but it has some cold weather issues,” said Phil Weber, Portland’s director of student transportation. “We are currently looking into a dual-fuel system.”

The system would use a combination of propane and gasoline to run the bus.

“The bus starts on gas, and once it warms up, it converts to propane. But then if they need power, like for hills, it reverts back to gasoline,” said Steve Huillet, pupil transportation consultant for the Oregon Department of Education. “As the newer technology with fuel injection came along, they were having problems with propane not having enough power to make the engines run; it didn’t have enough BTU content. So they had to go back to being able to use gasoline.”

The district requested and was granted a variance from the DOE to run its buses on this new system, which is produced by IMPCO, a Southern California-based company that produces alternative fuel system technology and components for internal combustion engines.

“We’re hoping to get the first system installed by mid-August. If it’s solid by the end of September, we’re going to move ahead with the installation on about 22 of our other Type-A buses,” said Weber, who has already seen the benefit of running propane buses. “We pay about $1.85 a gallon for propane and we get $0.50 a gallon back from a federal cash rebate back to the district through the IRS.”

The IMPCO system runs about $3,500 for the kit and $2,000 for installation.

Meanwhile, Blue Bird and Clean Fuels USA are promoting the new Propane-Powered Vision that promises the same oomph as diesel but emissions that meet 2010 EPA requirements.