Reducing emissions beyond the tailpipe with propane autogas

June 8, 2021
A recent study is making fleet owners think twice about the common perception that EVs offer the lowest emissions for public transit agencies.

The future of transportation looks greener every day and fleet owners in public transit see that vision better than most. Between government regulations and pressure from communities to reduce emissions, public transportation will continue to evolve over the next decade to achieve near-zero emission levels. 

As fleet owners evaluate the best way to achieve their sustainability goals, they need to take a close look at the energy source they select. Not just at what’s happening at the tailpipe of their vehicles, but also all the emissions that go into creating the energy source that powers the vehicle. As such, selecting “zero-emission” vehicles, like electric vehicles (EVs), may be short sighted. 

A new study is debunking the common perception that EVs offer the lowest emissions for medium- and heavy-duty fleet vehicles. In fact, in most of the United States, propane autogas produces fewer emissions than comparable electric vehicles. As the study shows, there is no such thing as a zero-emissions vehicle. 

Evaluating Emissions 

In a comparative analysis conducted by the Propane Education & Research Council, researchers found propane-powered medium- and heavy-duty vehicles provide a lower carbon footprint solution in 38 U.S. states and Washington, D.C., when compared to medium- and heavy-duty EVs that are charged using the electric grid in those states. This is due to the amount of carbon that is produced from each state’s unique energy mix for electricity generation using coal, petroleum or other energy sources. In addition, battery production is significantly energy and carbon intensive.  

While electric vehicles may have zero tailpipe emissions, emissions are generated prior to the wheels turning on the road through the electric grid and the powertrain (chiefly battery manufacturing) production. When comparing the difference in life cycle equivalent carbon dioxide (CO2eq) emissions of a single medium-duty vehicle, propane autogas on a national average emits 125 tons of CO2eq less than an electric medium-duty vehicle.  

Looking to the Future 

Many are quick to point out that the electric grid is going to keep getting cleaner. However, it’s important to note that propane autogas is also getting cleaner by leaps and bounds through new engine technology and renewable propane.  

Renewable propane is a byproduct of the renewable diesel and sustainable aviation fuel production process, which converts plant and vegetable oils, waste greases and animal fat into fuel. It has the same chemical structure and physical properties as conventional propane and can be used in any existing propane autogas engine. Because it’s produced from renewable raw materials, renewable propane has a lower carbon intensity than conventional propane and is cleaner than other energy sources.  

As such, the study found when renewable propane is considered, propane-powered medium-duty and heavy-duty vehicles currently provide a lower carbon footprint solution in every U.S. state except Vermont where most of the electricity is generated by hydroelectric powerplants.  

Cost-Effective Emissions Reductions 

While selecting a near-zero emissions energy source is a priority for many public transit fleets, at the end of the day, emission reductions also have to be cost effective for fleets to be able to implement these new solutions. But fleet owners that choose propane autogas don’t have to worry. When factoring in the cost of a new vehicle, regardless of fuel type and the costs for fuel, fluids, maintenance and repairs, propane autogas has the lowest cost of any fuel for the lifetime of the vehicle. 

The incremental capital cost for a medium-duty propane autogas vehicle, relative to its gasoline or diesel counterpart, is on average 15 percent. Comparatively, a similar medium-duty EV is more than 250 percent. Not to mention, the cost to purchase and install refueling equipment for a fleet of medium- or heavy-duty propane autogas vehicles is lower than the cost to purchase fast charger equipment for charging a comparable electric vehicle fleet in a comparable time frame.  

As the future of public transit becomes even cleaner, I encourage fleet owners to take a moment to see for themselves why propane autogas is an important energy solution for our environment. Learn more at 


Steve Whaley is the director of autogas business development for the Propane Education & Research Council. He can be reached at [email protected].

Propane Education and Reseach Council
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