An LPG-Air, Propane-Air or also called SNG (Synthetic Natural Gas) system, is a system that creates a gas that has nearly identical characteristics to Natural Gas, thus providing an ideal alternative to NG. Liquid LPG or Propane is converted to gas and mixed with air at a pre-set ratio. This resulting mixture is directly compatible with NG and can replace NG virtually in all applications without making any modifications or changes to the existing equipment. Such systems can also be connected directly to Natural Gas pipelines.  This makes operating the equipment easy, avoids lengthy and costly change-overs and guarantees uninterrupted energy supply. Propane has a vapor BTU content of approx.2500 BTU’s per cubic foot, whereas as NG has a BTU content of approx.1000 BTU’s per cubic foot. Since propane’s BTU content is much higher, it has to be "diluted". The vaporised LPG/propane is run through a propane / air mixer that mixes approximately 47% air and 53% of vapor propane, to create a mixture compatible with Natural Gas.

There are typically four main areas of such system usage:

• As a primary fuel source - In areas where Natural Gas is not available or will be available in the future
• As a Standby System - During "interruptible service" of NG from utility companies
• As a back-up System to restore supply when NG supply fails in instances such as natural disasters, maintenance works and accidental-drilling or due to problems with the NG network and
• For Peak Shaving