Cleaning Up

James Shamburger prepared to fuel one of the district's CNG buses. The fleet is one of the largest of its kind in the nation.

While diesel still reigns supreme in the school bus industry, many school districts are adopting alternative-fuel vehicles as quickly as their budgets allow. California’s largest school district, Los Angeles Unified, has been operating alternative-fuel vehicles for more than two decades, piloting buses powered by electricity, methanol, compressed natural gas, liquefied natural gas and propane autogas.

With hundreds of CNG- and propane-powered school buses, you could say LAUSD has the best of both worlds. The district has committed to these two options whenever it has the funds to replace older yellow buses. Thanks to partnerships developed over many years with local, state and federal air-quality organizations, LAUSD has been able to replace more than half its fleet with new, cleaner emission vehicles.

Currently the district operates the largest fleet of CNG school buses in the country. According to, there are an estimated 2,500 to 3,000 CNG school buses operating nationwide — out of the 480,000 total — but that number is growing.

Donald Wilkes, director of LAUSD’s Transportation Services Division, said his fleet of school buses is 100-percent clean, with 60 percent running on either propane or CNG, and the remainder on biodiesel. Most of the latter are equipped with diesel particulate filters (DPFs) to further reduce emissions.

Wilkes told STN the major metropolitan district has had three propane fueling stations since 2009 and more recently, has installed three CNG fueling stations, with one still under construction downtown. “We’re going to have a station there that will be able to slow-fill about 100 buses and will also have fast-fill capabilities,” he said. “Slow fill is a major time-saver. When drivers return for the day and park their buses, they simply plug in. So it fills as they are away from the bus.”

The district has installed far more slow-fill dispensers than fast-fill, he explained, with about 350 slow-fill posts at its Gardena lot alone. All 529 of their CNG buses are Type D transit models that have a range of about 300 miles on a full tank.

Time saved is money saved. LAUSD has realized additional cost savings by diversifying its fleet with two different alternative fuels. Wilkes estimates they are saving approximately $450,000 annually on fuel with the CNG and propane buses vs. the biodiesel across the district-owned fleet.

Currently he manages a yellow bus fleet of approximately 1,300 and a white fleet of 2,500 trucks, vans and cars used by school police, administration, maintenance and operations, and food services. While the district’s heavy-duty trucks run on LNG, he said similar options by Original Engine Manufacturers (OEM) are just not available for their light-duty trucks and vans.

“We’re making strides in that area,” Wilkes said. “It’s hard to find a light-duty, alt-fuel truck or van. For larger vans, you can upgrade to get a propane fuel system. So that’s one of the things we’ve been doing.”

“Ultimately we would like to move away from diesel fuel,” he continued. “Our district has passed an initiative to become all alternative fuel. When we replace vehicles, we always look for an alternative-fuel option.”

A Clean Fuels Leader

Included in that collective “we” is the district’s bus contractor, Student Transportation of America, a subsidiary of Student Transportation Inc. STA services approximately 10 percent of the district’s contract bus routes, all with propane buses, said Wilkes. The remaining routes are district owned and operated, including approximately 1,000 routes servicing students with special needs. Roughly two-thirds of the special needs buses in service run on propane fuel as well.

STI Chief Operating Officer Patrick Vaughan told STN the company will introduce its first 22 CNG buses for LAUSD as part of a new five-year contract taking effect this month. The company will source the compressed natural gas from other private contractors or the City of Los Angeles. “While these are STA’s first CNG buses for LAUSD, the company operates a large CNG fleet in service to other customers, including the CNG fleet serving the Riverside Unified School District,” said Vaughan.

He added that STA anticipates any new buses added to its LAUSD fleet will be ultra-low-emission or alternative-fuel vehicles.

“LAUSD has been in the forefront of alt-fueled buses for many years,” he said. “In 2003, the LAUSD Board of Education adopted its ‘Healthy Breathing Initiative’ that mandated a preference for alt-fuel and clean diesel in all future contracted service procurements. As a leader in the clean fuels movement, the district saw the health benefits to the community.”

In 2008 STA proposed a fleet of 75 propane vehicles in its successful bid to service 71 routes in LAUSD’s San Fernando Valley, Vaughan continued. In December 2009, the district purchased 90 Blue Bird buses with a General Motors 8.1-liter engine and CleanFuel USA liquid propane autogas injection system from A-Z Bus in Riverside, Calif., through a clean school bus grant from the Southern California Air Quality Management District (SCAQMD). CleanFUEL USA established the refueling infrastructure, and Delta Liquid Energy supplies the propane autogas.

Wilkes added that the district has also been operating Thomas Built Buses’ Type D CNG buses since 2010.

Pilots: Then and Now

Wilkes attributed much of the district’s success in alt-fuel implementation to the alliances it has with local utilities and fuel providers such as Southern California Gas and Trillium, as well as with agencies like the SCAQMD, California Energy Commission and the state Air Resources Board.

In 1990 ARB approved standards for cleaner burning gasoline and low- and zero-emission vehicles. In 2004 new statewide standards were passed to reduce diesel soot and smog-forming emissions by 90 percent from new large diesel engines. Two years later, ARB implemented the Lower Emission School Bus Program to reduce children’s exposure to both cancer-causing and smog-forming pollution, according to the organization’s website.

Wilkes said LAUSD’s use of CNG dates back to the early 1990s, when Alan Tomiyama helmed the Transportation Division. Southern California Gas first approached the district about piloting CNG vehicles in 1991. During Tomiyama’s tenure, Wilkes noted the department experimented with methanol, CNG and electric buses.

“We didn’t have a lot of success with the methanol. Electric wasn’t quite ready for the terrain we traveled, and the range was very limited,” recalled Wilkes, who has been at the district since 1983. “Even with CNG, there were some things that needed to be worked out — things that needed to be shared back with manufacturers of the bus types. It has just steadily gotten better and better as we’ve moved forward.”

He told STN the district has held talks with the Clinton Global Initiative, which recently launched pilots at two California school districts utilizing fully electric school buses that send power back to the grid when “plugged in” after hours.

“We’re on the list and hopefully we’ll be considered for this pilot,” Wilkes said. “We will look at how best to align ourselves to move in that direction four to five years down the line. There’s a lot of learning to be done there.”

He added that his department is already sending power back to the grid through its Gardena bus lot, which features solar panels like many of the District’s new school buildings.

Vital Partnerships

Wilkes emphasized that long-term partnerships have been “extremely important and helpful” to his department, which works diligently to tap grant funding opportunities without the benefit of having grant writers on staff.

According to SCAQMD representative Tina Cox, LAUSD has applied annually since the 2001 commencement of the agency’s Lower Emission School Bus program for school bus funding. To date, the district has received more than $94 million in funding from the SCAQMD and has replaced 620 older buses with new alternative-fuel buses and has retrofitted 319 newer diesel buses with particulate traps, she said.

“Of the over $94 million provided to LAUSD, roughly $9 million was provided for fueling infrastructure. LAUSD has used about half of the roughly $9 million provided for fueling infrastructure to further reduce their match to purchase school buses,” continued Cox. “For example, the school match is $15,000 for a bus, and we provide $14,000 per bus toward fueling infrastructure. LAUSD has used the $14,000 to further offset their match for the school bus, dropping their match for the bus to $1,000.”

Wilkes added, “AQMD has been a major resource in helping us receive the necessary funding and also accessing the compressors network with some other utilities that have done these types of installations. AQMD helped us to understand who’s out there, who’s done this and who’s had success.”

For example, the agency connected LAUSD with vendors who have a track record of successful CNG infrastructure installations. Wilkes said the district has successfully partnered with such vendors for lease-to-own programs and has thus been able to avoid high up-front costs.

“SoCalGas also offered a great deal of assistance in helping us understand getting compressors on site —the build-out of it, plus the permitting and licensing. They helped us through many of those hurdles, as well as the retrofitting of garages,” Wilkes continued, noting there are special ventilations required when technicians are servicing CNG vehicles, or any vehicle using a gas that’s under pressure.

“As the technology continues to advance, who better than a local utility to help you engage and work through all of the issues with the new technology in regard to the engine and the infrastructure, and also the maintenance?” Wilkes said.

He also pointed out that school districts don’t need to be as massive as LAUSD to benefit from alternative fuel vehicles, as they can find the same types of partnerships and opportunities for installing infrastructure.

“If you are medium to large and you know you’ll have a continued need for the services you provide, be they with your yellow fleet or our white fleet, I think that looking at installing your own infrastructure is the best and most cost-efficient manner to go,” advised Wilkes.

“As far as gas and diesel, I think the fluctuations in price are going to continue, but I think they’re going to steadily trend upward. In regard to cost of CNG and propane — which are certainly cleaner — those prices are always going to remain lower and to be much more steady. So I think that’s going to be a tremendous help to you as you budget and plan for the future.”