BioCNG differs from natural gas in that it is a renewable energy source produced biologically through anaerobic digestion rather than a fossil fuel produced by geological processes. Biogas is primarily composed of methane, carbon dioxide, and trace amounts of nitrogen, hydrogen sulphide and ammonia.  The precise composition of biogas depends on the type of feedstock and the production pathway; these include the following main technologies:

Biogas contains about 55-65 % of methane, 35- 44 % of carbon dioxide and traces of other gases, such as Hydrogen Sulphide, Nitrogen and Ammonia. Biogas, in its raw form, that is without any purification can be used as clean cooking fuel like LPG, lighting, motive power and generation of electricity Further, Biogas can be purified and upgraded up to 98% purity of methane content to make it suitable to be used as a green and clean fuel for transportation or filling in cylinders at high pressure of 250 bar or so and called as Compressed Bio-Gas (CBG) or Biomethane.