What is the Difference Between Biogas and Biomethane?

The primary difference between biogas and biomethane lies in their composition and purity. Biogas is a mixture of methane, carbon dioxide, and small quantities of other gases, produced by the anaerobic digestion of organic matter in an oxygen-free environment. On the other hand, biomethane, also known as "renewable natural gas," is a near-pure source of methane, typically produced by upgrading biogas. The main differences between biogas and biomethane are:

1. Composition: Biogas contains 50-70% methane and 40-50% carbon dioxide, along with trace amounts of other gases. Biomethane, after the purification process, has a methane content of around 95% or higher.
2. Purity: Biogas is a relatively impure form of gas, containing carbon dioxide, hydrogen sulfide, and water vapor. Biomethane, in contrast, is a highly pure form of gas, with most of the impurities removed during the upgrading process.
3. Applications: Biogas can be used directly for heat and electricity generation. However, to be used as a transport fuel or injected into the gas grid, it requires purification to become biomethane.
4. Upgrading Process: Biomethane is produced by upgrading biogas, which involves removing carbon dioxide, hydrogen sulfide, and water vapor. This process can be carried out using various technologies, such as water scrubbing and membrane separation.

In summary, biogas is a mixture of gases produced from the anaerobic digestion of organic matter, while biomethane is a purified form of biogas with a high methane content, making it suitable for a wider range of applications, including transportation and injection into the gas grid.

Comparative Table: Biogas vs Biomethane

Here is a table comparing the differences between biogas and biomethane:

In summary, biogas is a mixture of gases produced from organic matter in an oxygen-free environment, while biomethane is a refined form of biogas with a higher methane content. Biomethane is often considered a renewable natural gas substitute due to its higher methane content and versatility in various applications.