Propane is Decarbonizing School Bus Fleets

Written on: January 31, 2024

Renewable propane autogas will provide affordable, effective greenhouse gas reduction.

propane autogas for buses usa School is back in session, and propane is increasingly earning top grades for decarbonization.

This month, the U.S. Environmental Protection Agency (EPA) announced its latest Clean School Bus Grants. The number and percentage of propane autogas bus projects receiving grants increased. This demonstrates how propane autogas can substantively lower the carbon emissions of older gasoline and diesel school buses — more affordably than transitioning buses to electricity.

The arrival of renewable propane and other innovative blends will bring the carbon impact of autogas buses closer and closer to zero.

How Autogas Lowers Emissions

Converting a diesel or gas-powered school bus to propane makes a huge difference in its carbon intensity (the amount of carbon dioxide generated to produce a given amount of energy). Conventional propane’s carbon intensity is 14% lower than gas or diesel and 40% lower than the average U.S. grid-sourced electricity!

Propane school buses also have sulfur oxide emissions that are up to 24% lower than gasoline and up to 15% lower than diesel. Propane can lower sulfur oxide emissions by up to 44% compared to gasoline. Propane emits virtually no particulate matter and generates about 20% less carbon monoxide. This means better air quality for the children and adults that use these buses.

Less Expensive Than Electrification

While propane autogas’s environmental benefits are astounding, it also has an exceptional advantage over bus electrification in terms of affordability. Consider that the approximate cost to set up infrastructure for 10 electric vehicles with five level 3 fast EV chargers can reach $480,000. By contrast, you’ll only spend about $60,000 to set up a 1,000- to 2,000-gallon propane tank, which can service 10 autogas vehicles.

The Propane Education & Research Council has calculated that $1 billion, the rough amount the Environmental Protection Agency is spending on 2,350 electric buses, could purchase 29,000 propane school buses.
Propane buses can also qualify for the Alternative Fuel Tax Credit, which is part of the Inflation Reduction Act.

Operational Cost Benefits with Autogas

A recent case study presented by the Alternative Fuels Data Center of the U.S. Department of Energy shows the fantastic cost and performance benefits that Pennsylvania experienced by investing in a propane autogas bus fleet. Pittsburgh Region Clean Cities (PRCC) and the Eastern Pennsylvania Alliance for Clean Transportation (EP-ACT) helped 20 school districts deploy about 1,000 autogas buses over the last five years.

Tony Bandiero of the EP-ACT estimates that this fleet “reduced 5,000 tons of carbon dioxide per year.”

The switch to propane also lowered the total ownership cost of each bus by around $143,000 compared to diesel. As a predominantly U.S.-sourced fuel, propane regularly costs 30% to 50% less than gasoline or diesel, per Alliance AutoGas.

Autogas buses tend to run quieter and cleaner than diesel. This lowers the maintenance costs, extends engine life and improves performance in freezing conditions.

“Propane buses provide many advantages, like ease of start-up and cold weather usability,” says John Gonzales of the National Renewable Energy Laboratory.

This cold weather benefit is significant when comparing propane and electric vehicles, which are revealing more start-up issues in icy winter conditions. Two Michigan school districts have needed to pay for additional battery heaters to maintain capacity in colder months.

Meanwhile, in 2023, a Minnesota propane school bus reached the 250,000-mile mark. After 10+ years of service, it is still on its original transmission and has only needed to replace one fuel pump, one radiator, a headlamp, spark plugs and tank coating!

Renewable Propane Autogas

Propane autogas is a green alternative fuel that promises to become even greener as renewable propane gas and other innovative blends join the scene. Renewable propane’s organic and recycled feedstocks combine with a low-carbon production process, and the resulting fuel has a carbon intensity (CI) score that’s far lower than U.S. grid electricity.

Renewable propane made from unrendered, domestic used cooking oil has roughly 16% the CI of gird electricity. When you use camelina sativa, a seed plant that can grow on otherwise fallow land, as a feedstock, the fuel’s CI can be only about 5% that of the electric grid. Incorporating renewable dimethyl ether, you can bring the CI close to zero and potentially into net-negative territory. And today’s autogas engines can use all these renewable products without modification.

Autogas blends containing renewable propane promise superior carbon reduction at a price point that works for school districts. No wonder more and more communities are choosing propane buses over electric.

Reach out to the Renewable Propane Alliance for more information about autogas vehicles.