Logistics & Materials Handling Blog

Choosing The Right Forklift Fuel Type Part 3: Gas

by Paul Hinz
Filed under: Forklift Basics

Compressed Natural Gas (CNG) and Liquefied Petroleum Gas (LPG) … what’s the difference?

CNG and LPG are both gasses that forklifts use to operate. There are a few differences between the two and in today’s post the positives and drawbacks of each will be mentioned.

Compressed Natural Gas (CNG)

The process of producing CNG is quite simple. It is composed of methane which is a natural gas which is then filtered and compressed.


  • Produces significantly less emissions and pollutants compared to petrol (40% less Co2) which Help mitigate greenhouse gases
  • Safer than other fuels in the event of a spill/leak (lighter than air, and disperses quickly when released)
  • Considered to be safer than gasoline-powered vehicles
  • Due to the absence of any lead or benzene content in CNG, the lead fouling of spark plugs is eliminated
  • Lower maintenance costs – compared to other fuel powered vehicles (less caustic and cleaner, therefore engine will generally last twice as long)
  • Increased life of lubricating oils, as CNG does not contaminate or dilute the crankcase oil
  • Less likely to auto-ignite on hot surfaces, since it has a high auto-ignition temperature (540c)
  • Quick refuelling, taking less than 5 minutes (opposed to electric)


  • Greater emissions compared to LPG; requires more fuel to be burn to produce the same amount of energy.
  • Requires a greater amount of space for fuel storage than conventional gasoline powered vehicles, as it is stored as a gas at high pressure.
  • Less power than petrol/diesel/LPG
  • High pressure poses greater risk
  • Not as widely available, cost outlay usually higher due to converting LPG to CNG
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Liquefied Petroleum Gas (LPG)

LPG is a gas that is produced by mixing a variety of items including propane, butane and other chemicals and is artificially produced.


  • Low carbon emitting – burns cleanly with no soot and very few sulphur emissions.
  • Widely available
  • Non corrosive, non toxic and free of any additives, high octane rating (108RON)
  • Less tax and therefore cheaper to purchase
  • Safer option due to its lower pressure
  • Quick refuelling, taking less than 5 minutes (as opposed to electric)


  • Lower energy density per volume of unit compared to petrol, therefore fuel consumption is higher.
  • Heavier than air, thus will flow along floors posing ignition & suffocation hazards if not dealt with immediately.
  • Classified as “dangerous good” due to its destructive nature
  • Slightly more expensive than CNG. Costs approximately $21 a day in LPG (based on 70c/litre – using 3.75 litres/h for a 8 hr shift)
  • Less power than diesel/petrol (90%)