In the last decades, many companies have erected biogas plants worldwide. A lot of experience was cumulated, leading to a continuous process optimization of anaerobic fermentation and the development of new and more efficient applications. Overall, the basic knowledge of biogas production, the microorganisms involved, and the biochemical processes were widely extended. Biomass embraces products that are derived from photosynthesis that annually, saves an amount equivalent to several times the annual global energy consumption. Thus, biomass is unique in saving solar energy among various types of renewable energy sources. Biomass conversion processes can be physical (e.g. drying, reducing the size or compression), heat (such as coal) or chemical (e.g. biogas production). The final product of the conversion process may be in forms of either solid, liquid or gas. The flexibility to choose the physical form of fuel in biomass resources is an important advantage over the other sources of renewable energy.

Chemical energy in plants is absorbed by animals and humans who digest them. However, biomass is a renewable energy source in the sense that we can always grow the plants and trees, and there is always farmland for agricultural endeavors. There are some examples for the biomass fuels as wood, corn, fertilizer, and disposed garbage. Chemical energy of biomass fuels is released as heat while wood or other flammable garbage may be burned to generate steam and electricity. Burning biomass is not the only way to release their energy but they may be used in other forms of energy, such as methane, ethanol, and biodiesel. Methane is the main component of natural gas. Stinking materials like rotten garbage, agricultural waste and human waste, which are categorized as biogas or methane gas. India and China in the early 1930s began to construct the biogas system extensively. Sporadic studies in Iran in 1970s were conducted by research and academic institutes for biogas production that has led to the construction of biogas. By reviewing the pertinent literature and the energy production and consumption technologies of renewable resources, this study is going to recommend criteria for selection of biomass conversion technologies that are appropriate for energy production from rural solid waste in Tinouj village near Qom. The main objective of this study is to facilitate the selection of an appropriate design for domestic biogas installations.