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Aug 25

Why propane and school buses are perfect for each other

Posted on August 25, 2017 at 8:09 AM by Andy Tudhope


Across the country Clean Cities coalitions are making strides in reducing petroleum use, but we know there’s always more that can be done. That’s why we were happy to see a new study from the U.S. Department of Energy (DOE) which shows the real-life benefits of an often overlooked alternative fuel: propane autogas.

Propane autogas, also called liquid petroleum gas, is increasingly becoming a viable fuel substitute for many vehicle vocations, particularly within the medium duty vehicle market. Due to its modest up-front cost and simple infrastructure, propane can be economically used even for moderate fuel-use purposes. A recent DOE case study underlines this benefit by exploring the applicability of propane autogas for school buses.

The DOE’s case study, which reviewed five school districts nationwide with a combined 1,057 propane school buses, found that all five districts experienced lower operating costs. Several school districts observed a 50 percent reduction in maintenance and fuel costs per mile.

While fuel cost reduction was a substantial part of the savings, operators also noted significantly lower oil change expenses from the reduced volume of oil required along with longer drain intervals for the vehicles. Contrary to conventional belief, buses fueled by propane autogas even experienced similar fuel economy to diesel after adjusting for the energy content of each fuel.

Here in western Washington, at least ten school bus operators have made the decision to switch to propane autogas. We decided to check out the technology firsthand and visited Bryson Bus Sales in Everett, Washington. At first glance, we noted several advantages to buses powered by propane autogas that fall outside a traditional cost-benefit calculation. Propane buses warm up much more quickly than diesel buses, equaling less time to defrost windows and reductions in fuel waste. The buses are also much quieter than their diesel counterparts, making them less disruptive in residential neighborhoods and allowing bus operators to keep closer tabs on their passengers.

Perhaps the biggest benefit in replacing old diesel school buses with ones powered by propane autogas is the elimination of diesel particulate matter, a known carcinogen, which has been shown to disproportionally impact the health of children and older populations.[1]

Given the early reports (both local and national), it appears that propane autogas may just be the perfect fuel for school buses. Thinking about a conversion to propane for your organization? Check out the case study and let us know what you think! We’d be happy to talk it through with you.


-Western Washington Clean Cities Team