Biogas, composed largely of methane and carbon dioxide, is an exciting player in the field of emerging, renewable fuels chiefly because of its production process, which allows nature to do her thing under some controlled conditions, then picks up after her.

biogas train

photo by Barbarien


Producing biogas relies on a naturally occurring process in which organic matter is broken down by anaerobic digestion. The by-product of this digestion, mostly methane gas, is then upgraded to be the equivalent to natural gas, and can be compressed (CNG) or liquefied (LNG)—but unlike natural gas, biogas is renewable because its feedstock comes from a variety of solid wastes, sewage sludge, and manure and other animal by-products.

CO2 Emissions

However, the production of biogas, which captures methane, prevents that methane from reaching the atmosphere, reducing greenhouse gas emissions.

Fuel Blends

Like natural gas, biogas can be blended with hydrogen to create hydrogen/natural gas blends (HCNG), a blend with even fewer nitrogen oxide emissions than natural gas.


Biogas can very easily use the entire infrastructure already in place for natural gas.


It is renewable, and its production uses materials that otherwise collect in places such as landfills.

It is a high octane, clean-burning fuel which doesn’t threaten soil, surface water, or groundwater.

Its extremely similar to natural gas, meaning it is highly compatible with an already well-established energy source that currently provides the US with one quarter of its energy needs.


Its hydrocarbon emissions are far lower than gasoline, with the exception of methane, in which case they’re higher.

Again, like natural gas, on-board vehicle storage is an issue. In order to achieve a reasonable driving range, CNG needs to be stored at a very high pressure, around 3,600 pounds per square inch. LNG attempts to solve this space problem, but in order to turn the gas to a liquid, it must be cooled to -260°F (-162°C), a temperature so cold that it requires its own special on-board storage.

The Future

2007: United States Department of Energy estimates 12,000 biogas-powered vehicles worldwide, a number expected to increase to 70,000 by 2010.



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