Difference Between LPG and LNGLPGLiquefied Petroleum Gas (also called Autogas). LPG mostly propane (C3H8) or butane (C4H10), most commonly, mixes including b
CNG is generally cheaper than propane, primarily due to the lower cost of natural gas in comparison to propane gas. According to industry statistics, the cost of CNG is typically 30-50% lower than gasoline, while propane falls in between gasoline and CNG in terms of cost. cCwNO.