Which one of the following is the largest composition in biogas?

Biogas is a renewable fuel produced through the anaerobic decomposition of organic matter such as farm waste, animal dung, and municipal waste [3]. Its composition primarily consists of methane (CH4) and carbon dioxide (CO2). Methane is the largest constituent, typically ranging from 50% to 75% of the total volume [2][4]. Carbon dioxide is the second most abundant gas, usually making up 25% to 50% [4]. Other components like hydrogen, hydrogen sulfide, nitrogen, and ammonia are present only in trace amounts, often less than 1-3% [4]. Methane is the primary energy-bearing component, making biogas chemically similar to natural gas and suitable for heating, electricity generation, or as a vehicle fuel after upgrading [1]. Therefore, methane represents the largest portion of the biogas mixture.

Sources

1. [3] https://www.epa.gov/lmop/renewable-natural-gas
2. [2] NCERT. (2022). Contemporary India II: Textbook in Geography for Class X (Revised ed.). NCERT. > Chapter 5: Print Culture and the Modern World > Biogas > p. 117
3. [4] https://www.sciencedirect.com/topics/engineering/biogas
4. [1] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > 4.1 BONDING IN CARBON – THE COVALENT BOND > p. 60