Transportation Fuel Conversions

Natural gas has been fueling vehicles since the early 20th century. Because it is a gas, it must be stored in either a compressed gaseous (CNG) or liquefied state (LNG), the difference being primarily vehicle specific. For example, most consumer vehicles can run on a dedicated CNG supply or a bi-fuel application, having the flexibility of CNG and gasoline.

Most LNG applications are available for commercial trucks that need a longer range. Heavy duty trucks that run on two fuels are referred to as “dual-fuel” vehicles.

The use of CNG as a transportation fuel is continuing to emerge as an emissions-reducing and cost-effective alternative to diesel and gasoline, with estimates of a 10% growth in usage by 2025 worldwide. Pennsylvania has seen a number of transit agencies, delivery services, waste hauling vehicles and heavy-duty trucking companies make the switch to CNG in the past decade, thanks to abundant and lower-cost natural gas supplies. PIOGA members are directly involved in this market segment, providing engineering, mechanical and contractor expertise.

Among the advantages of CNG over other types of transportation fuel are reduced maintenance costs and engine wear and tear, increased life of lubricating oils and cleaner emissions. Emissions of carbon dioxide, carbon monoxide, nitrogen oxide, sulfur dioxide, particulate matter and unburned hydrocarbons from CNG are all far lower than those from diesel or gasoline, and equivalent fuel costs for CNG are about $1 less per gallon than the cost of diesel. It is estimated that the pay-back period to recover the cost to convert an engine to CNG fuel is 18-24 months.

Pennsylvania continues to install CNG fueling stations to serve both private fleets and the public. The state currently offers 90 such public stations along the turnpike and state and federal highways, with many more planned for the years ahead.

Did you know?

  • Natural gas is fueling electric vehicles too
    • Pennsylvania natural gas is fueling approximately 33% of Pennsylvania’s electric grids.
  • One-third of all new transit buses run on natural gas
    • Replacing one older diesel bus with a natural gas bus is the equivalent to taking 21 cars off the road.
  • 30% of heavy-duty trucks will convert to natural gas by the end of 2025.


For more on fuel comparisons, engines, safety, laws, public fueling stations:

More on Commercial Vehicles and Fleets:


Pennsylvania Resources and Grant Opportunities for Alternative-Fueled Vehicles

The Pennsylvania Department of Environmental Protection (DEP) offers grant funding for clean, alternative fuel projects in Pennsylvania and investment in Pennsylvania’s energy sector. The primary goals of the Alternative Fuels Incentive Grant (AFIG) Program are to improve Pennsylvania’s air quality and reduce the consumption of imported oil through the use of homegrown alternative fuels that will help the state’s economy and environment.

DEP also is administering new grant and rebate programs to improve air quality in Pennsylvania, funded by the $118 million settlement with Volkswagen Group of America as Pennsylvania’s share of the settlement for allegations of cheating on U.S. Environmental Protection Agency diesel emissions tests.

Announced in May 2018, the initiative, Driving PA Forward, is aimed at permanently reducing nitrogen oxide emissions statewide by as much as 27,700 tons by accelerating the replacement of older diesel engines with cleaner technologies. Eight grant and rebate programs will be available over the next five years, with as much as $39 million available for disbursement in the first year alone.

More information on the grant and rebate programs, including program guidelines and application instructions for open grant and rebate programs, can be found at