Biogas vs Biomethane: Differences, & Comparison

In this guide, we discuss biogas and biomethane.

We explain what each one is, but also identify the main differences between them, and compare them as well.

We also outline how compressed natural gas (CNG), and also liquefied natural gas (LNG), both relate to biogas.

 

Biogas vs Biomethane: Main Differences & Comparison

Biogas is essentially the raw gas that is produced from the digestion of organic material and organic waste.

Raw biogas can be refined into biomethane, which has had carbon dioxide and other elements removed so it can meet natural gas industry standards.

So, biomethane is a type or form of biogas.

That’s the main difference between the two.

 

Biogas

What Is Biogas?

Biogas is gas derived from the anaerobic decomposition of organic waste or organic material

 

Types Of Biogas

In an anaerobic biogas digestor, raw biogas is typically produced.

However, biogas in the form of methane is also produced at landfills from decomposing organic waste. This is known as landfill gas (sometimes called LFG).

Both of these biogases can be captured and used.

Biomethane, CNG and LNG can also be made from raw biogas.

 

How Is Biogas Made?

Biogas occurs in nature, in landfills (when organic waste dumped at landfills breaks down), and at livestock manure management systems.

However, biogas is produced industrially at biogas plants, whereby a range of organic materials and types of organic waste can undergo anaerobic digestion in a biogas digestor.

Raw biogas is produced from these digestors.

 

What Is Biogas Used For?

Raw biogas can be used with little or no processing or refinement. It can be burnt for heat, or can be used for electricity using a range of methods.

 

Biomethane (Renewable Natural Gas – RNG)

What Is Biomethane?

Biomethane is also referred to as renewable natural gas, or RNG.

It is raw biogas that has been processed or refined, so that it can meet natural gas industry standards.

 

How Is Biomethane Made?

To make biomethane, elements like carbon dioxide, water vapor and other trace gases are usually removed from raw biogas.

 

What Is Biomethane Used For?

Biomethane can be used in existing natural gas infrastructure, such as pipelines.

It can replace a certain percentage of natural gas used.

It can be used for the same purposes as natural gas, such as heating and cooking.

 

What About Compressed Natural Gas (CNG) & Liquefied Natural Gas (LNG)?

Biomethane can be converted into either CNG or LNG, and used as a vehicle fuel.

 

What About Landfill Gas?

Landfill gas is mostly methane.

Methane is produced when organic waste breaks down is landfills under anaerobic conditions.

Landfills with landfill methane capture systems can capture and use the methane as an energy source. 

This form of biogas is usually different to the biogas that comes from controlled biogas digestors, as the nutrients can’t be recycled, and obviously the conditions of digestion can’t be controlled.

 

Sources

1. https://www.eesi.org/papers/view/fact-sheet-biogasconverting-waste-to-energy

2. https://www.nationalgrid.com/stories/energy-explained/what-is-biogas

3. https://en.wikipedia.org/wiki/Biogas#Benefits_of_manure_derived_biogas

4. https://www.eia.gov/energyexplained/biomass/landfill-gas-and-biogas.php

5. https://www.iea.org/reports/outlook-for-biogas-and-biomethane-prospects-for-organic-growth/an-introduction-to-biogas-and-biomethane

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