Compressed Natural Gas Vs. Propane

Compressed Natural Gas

• Compressed natural gas (CNG) is a clear, odorless and non-corrosive fuel used as an alternative fuel for vehicles. It is natural gas that has been compressed to a pressure of 3,600 PSI and kept in a gaseous form, instead of being turned into a liquid. Compressed gas is delivered to CNG fueling stations via distribution pipelines, where the CNG is stored underground. Vehicle operators pump the CNG into the vehicle from stations that look very much like traditional, liquid gas stations. A vehicle must be specifically designed and manufactured to run on CNG or have dual fuel capabilities to run on CNG, diesel or "regular" liquid gasoline.

Propane

• Propane fuel comes in two distinct types -- liquid and vapor. Most homes that use propane do so with the vaporized, gaseous form. The familiar containers used for barbecue grills and the big outdoor tanks outside of homes contain propane in its vapor form. Vaporized propane is distributed via pipelines, similar to how natural gas is delivered. The liquid form of propane is referred to as "LP." Like CPG, LP is an alternative fuel for vehicles fed through pipelines to LNG fueling stations or transported to the stations by truck for pumping by vehicle operators.

Similarities

• Both CNG and propane "compete" with natural gas, electricity and liquid petroleum gasoline. Because both are listed on the 1990 Clean Air Act as clean energy alternatives and qualify for applicable federal and state tax credits. CNG and propane come from domestic resources in the U.S. and reduce dependency on foreign energy. However, the other similarity that CNG and propane share is somewhat of a downside. Both lack a widespread infrastructure of filling stations to make them a convenient alternative fuel for automobiles. As of 2010, only Honda provided an all-CNG model -- the Honda Civic GX CNG. Both CNG and propane have a way to go in getting consumers to make the switch, and manufacturers and suppliers have a long way to go to make them accessible for use.

Differences

• Propane is the clear winner over CNG in terms of variety of uses and applications. Propane can power and fuel everything, from cars to barbecue grills and indoor fireplaces. CNG fueling choices are limited. CNG is exclusively used for vehicles. Natural gas -- CNG's "mother" -- steps in when gas is chosen to fuel residential and commercial equipment and appliances. CNG and propane also have differences in terms of their suitability as an alternative fuel choice for vehicles. CNG is best suited for light- to medium-heavy-duty vehicles, ranging from automobiles to medium-size trucks. This is because CNG tanks take up quite a bit of storage space. As a result, LPN (liquid natural gas) wins out over CNG as a fuel alternative for big trucks with commercial loads that need the space for transporting items -- not fuel.