File photo

File photo

There is a compelling economic, air-quality, and common-sense case to be made for investing in new diesel technology to get kids to and from school. New diesel-powered school buses are now a cost-effective, safe, reliable, durable, and near-zero emissions option for all school districts.

Today, 94% of the roughly 500,000 school buses operating in the U.S. are powered by diesel engines. With 1.6 million more kids riding in the newest diesel buses this year — ones outfitted with the cleanest, most fuel-efficient engine technology — diesel clearly remains the fuel of choice for most school districts.

Why is that, particularly when we continually hear about new options like electric and propane?
The answer: diesel provides the best combination of safety, reliability, operating range, durability, low-cost ownership and operation, widely available fueling and repair networks, expanded utility beyond routine routes, and ability to use high-quality renewable biofuels. Additionally, today’s generation of diesel features an important new attribute: near-zero emissions.

Thanks to diesel’s low cost relative to other propulsion options, more emissions can be reduced by replacing older buses with the new generation of diesel buses. On the road since 2010, these buses are equipped with the most advanced emissions-control technology available: diesel particulate filters and selective catalytic reduction systems. These technologies capture nearly all fine particulate matter and eliminate smog-forming nitrogen oxide (NOx) emissions to near-zero levels.

Many school districts have also found they can further lower their carbon footprint and overall emissions by switching from 100% petroleum diesel to blends of advanced, renewable biodiesel fuels. This other low-carbon, greenhouse gas emissions-cutting option does not require additional investments in refueling infrastructure, and can cut carbon emissions by at least 50% overnight. In the case of renewable diesel fuel, the greenhouse gas-eliminating power is over 80%.

Another important consideration is purely economic. Is the high-priced investment in electric school buses — vehicles that only travel a few thousand miles a year, for just a few hours a day, and operated only nine or 10 months a year — a strong case for the use of limited education funding dollars?

Some analysts conclude that all-electric buses may come with a price tag three times that of a new diesel bus. School districts looking to replace older buses frequently operate within very tight budgets. According to the Manteca/Ripon Bulletin, California’s Manteca Unified School District determined that going all-electric would cost almost $4 million more — big money for a small school district — than replacing its aging fleet of 32 buses with new diesel options.

Beyond direct costs, many rural and suburban districts operate in remote areas or in extreme temperature conditions, with established routes that may extend beyond the range capability of a battery. Other school districts may not have the financial wherewithal to invest in a network of expensive charging stations.

The city of Aspen, Colo., determined that the cost of purchasing and installing a single charging station for transit buses came with a $160,000 price tag, according to CleanTechnica. That’s about the cost of another new diesel bus, which amplifies an important point: acquiring electric buses and the requisite infrastructure actually can have the unintended consequence of having more kids riding on older buses, generating higher overall fleet emissions, due to cutbacks on the basic turnover of the existing fleet.

Ezra Finkin is the director of policy for the Diesel Technology Forum.

Ezra Finkin is the director of policy for the Diesel Technology Forum.

For most fleets, choosing the new diesel option may actually reduce emissions because for the same amount of limited pupil transportation dollars, more aging and higher-emitting buses can be replaced at a lower cost than buying a few electric buses. The state of Arizona determined that, for a fixed investment in new school buses, three times as many emissions could be reduced by replacing more aging buses that produce higher emissions with the diesel option than with all-electric buses.

All fuels and technologies have pluses and minuses. Electric buses may have no tailpipe emissions, but the electrons that flow into the buses’ batteries are generated mostly by fossil fuels that produce emissions.

The bottom line: Getting more kids to school safely, affordably, and reliably within the means and budgets of school districts is best done by investing in the latest generation of advanced diesel technology.

Ezra Finkin is the director of policy for the Diesel Technology Forum, which advocates for clean diesel technology. The nonprofit education organization is dedicated to raising awareness about the importance of diesel engines, fuel, and technology. Learn more at