Renewable Natural Gas (Biomethane)

Renewable natural gas (RNG)—also known as biomethane or biogas—can provide a clean, easily controlled source of renewable energy from organic waste materials, replacing fossil fuels with a sustainable carbon neutral fuel option.

What is biogas?

Biogas is generated when bacteria degrade biological material in the absence of oxygen, in a process known as anaerobic digestion. Biogas is a renewable fuel, primarily a mixture of methane (also known as marsh gas or natural gas) and carbon dioxide (CO₂).

Landfill gas is biogas produced by organic waste decomposing under anaerobic conditions in a landfill. The waste is covered and compressed mechanically by the weight of the material that is deposited from above. This material prevents oxygen from accessing the waste and anaerobic microbes thrive. This gas builds up and is slowly released into the atmosphere if the landfill site has not been engineered to capture the gas.

Biogas can provide a clean, easily controlled source of renewable energy from organic waste materials, replacing fossil fuels with a sustainable carbon neutral fuel option.

What is biomethane?

Municipal solid waste landfills account for over one quarter of the total methane emissions in the United States. Landfill gas is a particularly attractive natural gas supply option because it is a low-cost feedstock source due to the minimal processing required to remove the impurities to produce biomethane.

Biogas is normally rich in methane (about 65%) and impurities of hydrogen sulfide (H₂S), CO₂ and water. Technology is commercially available to remove H₂S, CO₂ and water contaminants present in the biogas and landfill gas through processing to produce high-purity natural gas (biomethane) suitable for vehicles.

Therefore, biomethane is simply pipeline quality natural gas that can be used directly or added to existing supplies.

Why biomethane?

Capturing landfill gas or biogas for processing into biomethane suitable for vehicles has significant benefits, in addition to the benefits of natural gas.

• Using biomethane as a renewable fuel has significant greenhouse gas (GHG) benefits.
• Unlike naturally occurring methane emissions, biomethane is converted to CO₂ during combustion (a 21 times greenhouse gas savings).
• Biomethane is a renewable resource that can displace fossil fuel by 100%.
• Biomethane does not compete with food production.
• The biomethane that is used as fuel in place of petroleum-based fuels produces less GHG than the fuel it replaced.