CAZENOVIA — During the Nov. 18 Cazenovia Central School District Board of Education (CCSD BOE) meeting, Christine Goossens, transportation advisor at Leonard Bus Sales, delivered a presentation on “clean” diesel buses titled “Understanding Vehicle Emissions.”
CCSD Assistant Superintendent/School Business Official Thomas Finnerty introduced Goossens and explained why the district invited her to speak.
He stated that for the past five years or so, CCSD has purchased nothing but gasoline buses. However, the administration would now like to consider clean diesel as an alternative to gasoline.
According to Finnerty, electric buses, another alternative, are currently cost-prohibitive at $400,000 to $500,000 per bus.
“For the next couple of years, we’d like to consider possibly entertaining the idea of clean diesel to give us an option,” he said. “Because right now, we have one provider for gasoline, so that kind of locks us into ‘one provider, one price,’ whereas clean diesel is an option with a few other providers.”
Goossens, who handles Central New York for Leonard Bus Sale, began her presentation by clearing up some common misconceptions about diesel emissions.
She addressed the idea that gasoline engines are cleaner than diesel by first noting that gasoline and diesel engines both have exhaust emissions.
“Where one leads, the other falls short,” she said. “I’ll show you some slides on different emissions that come out of the tailpipe and what those levels are. [Today, both] are well below the [US Environmental Protection Agency (EPA)] standards for on-the-road vehicles.”
She also distinguished between on-road vehicles, such as diesel buses, and off-road vehicles, such as diesel farm tractors, which must meet different standards.
Goossens next discussed the misunderstanding that gasoline engines are naturally clean. She explained that gasoline engines rely on catalytic converters, positive crankcase ventilation, and multiple sensors to burn clean; without such systems, they would not meet EPA and California Air Resources Board standards.
When addressing the claim that diesel engines are “highly polluting,” Goossens said that statement would have been true for on-road vehicles 25-30 years ago; today, however, modern aftertreatment systems allow for low emissions from the tailpipe.
She responded to the misconception that gasoline engines are cheaper to operate by stating that studies conducted over multiple years and fleets show that gasoline- and diesel-powered buses are pretty much cost-neutral when compared to one another over their lifecycles.
Finally, the speaker argued against the idea that diesel bus technology has not changed over the years.
“That is a big misconception because the modern aftertreatment systems are designed to meet and exceed tailpipe emissions standards,” she said, adding that as the standards have evolved, so too has technology.
According to Goossens, engine manufacturers must meet new EPA standards every few years. The next new standard is set to be released in 2027.
“It’s even going to be better than it is today,” she said. “You’re going to reduce NOx [(Oxides of Nitrogen)] emissions. Just as a disclaimer, really the only zero-emission vehicles will be electric, but there are a lot of challenges [with] electric when it comes to infrastructure, etc. But for the time being, diesel is extremely clean.”
Goossens next presented the BOE with several figures. Each graph showed how diesel, gas, and propane engine outputs compare to each other and the EPA standard for a particular emission type.
The first, a graph of NOx, showed diesel outputs as higher than gas and propane but well below the standard.
The next showed that gas and diesel outputs of non-methane/hydrocarbon are equal and well below the standard.
When looking at the carbon monoxide exiting the bus’s tailpipe, the diesel output is lower than the other engine types and well below the standard.
Another figure showed diesel particulate matter output as lower than the standard but, in certain cases, higher than propane and gas.
“Diesel is a little bit higher on this end of things,” said Goossens. “We have found that it’s mainly because of [vehicle weight]; diesels tend to be a lot heavier. They are showing that there is a lot of particulate matter coming from the tires these days, but that is very tough to measure.”
According to Goossens, tires generate 6 million tons of particulate matter annually, and 200.000 tons end up in the oceans.
She also reported that US automobiles emit five pounds of tire particles per year, per vehicle; tire emissions from electric vehicles are 20 percent higher than those from fossil-fueled vehicles; and particulate matter from tires and brakes far exceeds the mass of emissions from tailpipes.
Goossens presented the references she used for her presentation and then opened the floor to questions from the board.
BOE member Ron Luteran inquired whether diesel or gas is more cost-effective in terms of mileage.
Goossens said it ultimately depends on the cost of diesel versus gasoline.
“I can tell you that on average, [if] you pull it from the EPA, diesel engines get about nine miles per gallon,” she said. “If you’re getting nine miles per gallon from your diesel, you’re probably getting [about] 4.5 to five on your gas. So, if you think about the cost of that, it’s almost double.”
From the audience, CCSD Transportation Supervisor Karen Brouillette announced that the district’s gas buses currently get about four miles per gallon.
When Goossens informed the BOE that Leonard Bus Sales currently offers electric buses in addition to diesel buses, Superintendent Christopher DiFulvio inquired how soon CCSD could hypothetically get an electric bus if voters authorized the district to try one out.
NYS has mandated that all new school buses purchased must be zero-emission by 2027, and all school buses operating within the state must be zero-emission by 2035.
In response to DiFulvio’s question, Goossens explained that Leonard’s factory has a new electric vehicle (EV) manufacturing facility.
“A lot of the bus goes through the line with the other diesel buses, and then they bump out and go to this EV center,” she stated. “With that being said, we could probably get an electric bus within four or five months — six months by the time it’s delivered. I think right now, they are comfortably manufacturing 15 buses a day.”
According to Goossens, the district would likely get an electric bus sooner than a diesel bus. However, the company would not add an electric bus to CCSD’s fleet unless the district already had a charging station for that vehicle.
During a discussion on electric buses later in the meeting, Finnerty stated that out of the district’s 24 bus routes, 15 could possibly be completed by an electric bus.
“Nine of them simply cannot; there is not enough range,” he said.
BOE member Dr. Jan Woodworth commented that, based on the number of hills in the district and the mileage decrease she notices in her hybrid car in the winter, she suspects the number of routes an electric bus could complete would end up being lower.
“I just wouldn’t trust those numbers without trying a bus out for a little while,” she said. “That’s just my gut [feeling]. I see a 25 percent difference in my gas mileage between the winter and the summer.”
In response, Finnerty reported that the best claim he has seen is that an electric bus can travel 120 miles, but he thinks the reality is closer to 80 to 100 miles.
BOE President JoAnne Race suggested the district contact northern school districts with electric buses to ask how their vehicles run in the cold.
BOE meetings are open to the public, and community members are encouraged to attend. Meeting dates are listed on the district website and the school calendar. For more information, visit cazenoviacsd.com. To contact the entire board, email [email protected].
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