Biogas power is the product of the fermentation of organic matter from plant or animal in an anaerobic environment. This fermentation also called bio-methanation occurs naturally in certain environment with little or no oxygen, or spontaneously in the process of decomposing organic matter (p. ex. composting) and artificially in digesters of biomethanation power plants (p. ex. energy crops, agricultural organic waste, agro-industrial waste, or sewage sludge, etc.).

Bio-methane is a mixture consisting essentially of methane (CH4) from 50 up to 70% and carbon dioxide (CO2), with residual water, and hydrogen sulfide (H2S) in form of steam. The biogas energy comes mainly of methane, howerver biogas is a renewable form of fossil energy, respectively of natural gas containing methane, as well as butane, propane and other gaseous elements.

The gas is purified to remove carbon dioxide and hydrogen sulfide, bio-methane can be injected directly into the gas distribution network. Nevertheless refining process of bio-methane uses expensive advanced technologies, mainly profitable for agro-industrial types of power plants, then the bio-methane can also be converted through unit combined power-heat into heat and electricity commonly called TOTEM (Total Energy)!