What is RNG? An introduction to renewable natural gas

Renewable natural gas (RNG) is a clean, domestic energy source that turns waste streams into usable energy. While natural gas currently accounts for 36% of U.S. primary energy consumption, according to the U.S. Energy Information Administration (EIA), it is a fossil fuel that contributes to climate change. Natural gas powers turbines for electricity and serves as a major heating source, making it the top source of U.S. utility-scale electricity generation. However, burning natural gas releases carbon that was once stored underground, creating a tension between its widespread use and global climate goals. RNG offers a way to bridge that gap.

What is RNG?

Renewable natural gas (RNG) is a form of natural gas that is produced from organic waste. Chemically, RNG is essentially interchangeable with traditional natural gas, as both are primarily composed of methane. Yet the methane in traditional natural gas comes from fossil sources, while the methane in RNG comes from anaerobic digestion of organic waste.

Renewable natural gas (RNG) is considered renewable because its feedstock—organic materials like food waste or decaying plant matter—can be regrown and helps draw carbon back into the soil. Unlike conventional natural gas, which releases greenhouse gases that would otherwise remain locked underground for millennia, RNG emits carbon that would have entered the atmosphere naturally if the organic waste were left to decompose.

As a result, RNG adds virtually no new emissions beyond those associated with its production and distribution. In fact, it can even be considered climate-positive because it captures methane that would have otherwise been released into the atmosphere and converts it into carbon dioxide (CO2). Methane is a much more powerful climate pollutant, with a significantly higher warming impact than CO2, especially in the near term.

Carbon dioxide (CO2) may be the focal point of many climate discussions, but methane is actually about 30 times more potent at trapping heat, especially in the short term.  For this reason, methane capture offers more immediate and significant climate benefits than capturing CO2. The EPA has stated: “Because methane is both a powerful greenhouse gas and short-lived compared to carbon dioxide, achieving significant reductions would have a rapid and significant effect on atmospheric warming potential.”

So, RNG addresses both waste management and greenhouse gas emissions challenges in an especially effective manner.

Typically, the term RNG is used in North America, while biomethane is used in Europe, yet the two have the same meaning.

How is RNG produced?

The RNG production process includes five primary steps:

1. Organic waste collection: First, the feedstock for the RNG needs to be collected. This organic waste might come from agricultural waste, food and other landfill waste, wastewater facilities, etc.

2. Anaerobic digestion: Next, microbes break down the organic waste in an anaerobic environment, meaning an area without oxygen. This process has two byproducts:  

• One byproduct is digestate, a mixture of liquid and solid material produced during the digestion process. It has practical applications, such as being used as a nutrient-rich fertilizer.

• The other is biogas, which can be used directly as an energy source, but it has a higher amount of carbon dioxide than natural gas, so it's not a 1:1 replacement at this stage.

3. Biogas purification: Once biogas forms, it can then be upgraded into RNG through a process that removes impurities like carbon dioxide and moisture, which increases the concentration of methane. Biogas generally has a methane content of roughly 45-75%. After purification, the resulting RNG has a methane content of typically at least 90%, but often 96-98% when used in natural gas pipelines.

4. Pipeline injection: After going through sufficient purification, RNG can be injected into pipelines where it mixes with natural gas.

5. RNG delivery: RNG gets delivered to end customers through existing natural gas pipelines, similar to how renewable electricity from solar gets delivered to customers after the electrons mix with other sources in a power grid. To prevent double-counting of emissions reductions and to ensure that the right parties are credited with the purchase of RNG, the gas is tracked via environmental attribute certificates.  

Benefits of RNG

RNG can provide both environmental and economic benefits to those who produce and buy the gas. Some of the top benefits of RNG include:

• Reduced emissions: RNG usage prevents emissions that would otherwise come from natural gas usage, and it also removes emissions that would otherwise enter the atmosphere from organic waste decomposition.  

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Altogether, depending on the feedstock, RNG can reduce greenhouse gas emissions by up to around 125%, compared to traditional natural gas emissions.

• Improved waste management: Instead of allowing organic waste to decompose and potentially create environmental hazards, anaerobic digestion captures and controls the process to produce RNG. This approach leads to cleaner, more efficient waste management for farms, municipal wastewater treatment plants, and similar facilities. Additionally, it creates new revenue opportunities—for example, farmers can sell agricultural waste for RNG production.

• More cost-effective renewable energy source: While some decarbonization strategies involve converting from gas to electric appliances and expanding electric grid infrastructure, the fact that RNG uses existing natural gas infrastructure can make it significantly more cost-effective than electrifying homes and businesses to receive other types of renewable energy. According to the American Gas Association (AGA), RNG could reduce emissions at anywhere from one-tenth to one-third of the cost of all-electric homes using heat pumps.

• Improved energy security: There's currently enough feedstock to produce enough RNG to meet the energy needs of every U.S. household that currently uses natural gas, according to a recent study by the AGA. That could help the U.S. improve energy security, rather than relying on imported fossil fuels.  
  
  While RNG can often be more cost-effective than certain electrification strategies, electrification still offers benefits—such as reducing carbon monoxide emissions from gas combustion. The advantage is that RNG can also generate electricity, giving buyers an additional renewable option where electrification is implemented. This flexibility helps strengthen energy resiliency and diversify clean energy sources.

RNG Use Cases

RNG can be used anywhere natural gas is currently utilized and can also generate electricity for vehicles and systems transitioning from petroleum or natural gas engines to electric power. Some of the most common applications for RNG include:

• Heavy-duty vehicle transportation: Heavy-duty vehicles like buses and trucks often run on compressed natural gas (CNG) or liquified natural gas (LNG); either way, RNG can be used as a direct replacement for these fuels.

• Maritime fuel: RNG can replace petroleum products like heavy fuel oil (HFO) used to power marine vessels like container ships. Relatedly, it can also power electrified port operations.  

• Sustainable aviation fuel: RNG can be converted into a liquified jet fuel, helping the aviation industry as it shifts more toward sustainable aviation fuel (SAF).

• Hydrogen production: Hydrogen is often produced from natural gas, where the methane in the gas reacts with steam to separate the hydrogen atoms. Instead of using a fossil fuel source, however, the same production could be done with RNG, resulting in green hydrogen that can lower the carbon intensity of other products made from hydrogen, such as ammonia-based fertilizers and other industrial chemicals.

• Thermal energy: RNG can replace natural gas that's used as a thermal energy source, such as heating boilers and furnaces. This can be useful at both an industrial and residential scale.

• Electricity: While not always as efficient at producing electricity as other renewable sources, RNG has the advantage of being able to drop into existing infrastructure that powers much of the U.S. electrical grid from natural gas. RNG can also be produced on demand to fill gaps created by renewables like wind and solar.

RNG regulations/policies

Multiple policy frameworks, at the US federal and state levels, as well as in Canada and Europe, reward the use of RNG as a replacement for fossil fuels through policy and financial incentives. These include:

U.S. Federal policies

• Renewable Fuel Standard (RFS): This EPA standard mandates replacing petroleum-based fuels with increasing amounts of renewable transportation fuels, including RNG.

• Investment & production tax credits: RNG producers and infrastructure developers may qualify for clean-energy-related federal tax credits, such as under the Inflation Reduction Act (IRA) and One Big Beautiful Bill Act (OBBBA).

• Bipartisan Infrastructure Law: The 2021 Bipartisan Infrastructure Law provides federal funding to upgrade waste and agricultural facilities for more RNG development and distribution.

These federal programs and incentives remain active in 2026 and have not been rolled back, continuing to support RNG and other clean fuels nationwide.

U.S. State policies

• California Low Carbon Fuel Standard (LCFS): This fuel standard uses a credit-based system for transportation fuels. Low-carbon fuels like RNG can generate credits that can be sold to other regulated parties that have not achieved sufficient carbon-intensity reductions.

• Oregon Clean Fuels Program (CFP): Oregon's CFP is similar to California’s LCFS, with RNG producers able to receive financial incentives to lower the carbon intensity of fuels.

• Other state-level RNG mandates and incentives: States such as New York, Colorado, and Washington are implementing policies and subsidies to encourage clean energy usage, including RNG, in areas like transportation, waste management, and heating.  

EU policies

• FuelEU Maritime Regulation: This regulation sets greenhouse gas intensity reduction targets for marine fuels used by ships calling at EU ports. Low-carbon fuels such as biomethane can help operators meet targets and avoid penalties; while pooling and credit banking mechanisms provide compliance flexibility.

• ReFuelEU Aviation: Requires increasing shares of Sustainable Aviation Fuel (SAF) in jet fuel at EU airports, creating demand for advanced biofuels and synthetic fuels. RNG-derived SAF can generate compliance value and support lifecycle GHG reduction goals.

• Other EU renewable fuel incentives: Under the Renewable Energy Directive (RED II/III), biomethane and RNG qualify for Guarantees of Origin, sustainability certification (e.g., ISCC-EU), and access to credit systems in transport sectors. Additional benefits include zero-rating under EU ETS, national support schemes, and funding through REPowerEU and biomethane partnerships.

Canadian federal policies

• Canada Clean Fuel Regulations (CFR): This federal program uses a credit-based system requiring fuel suppliers to reduce carbon intensity. Low-carbon fuels like RNG can generate tradable credits, and additional credits can be earned through electrification and other GHG-reduction projects.

Canadian provincial policies

• British Columbia Low Carbon Fuel Standard (LCFS): Like California’s LCFS, BC’s program allows RNG and other renewable fuels to earn credits for lowering carbon intensity. Credits can be sold to regulated parties that need compliance flexibility.

• Other provincial RNG mandates and incentives: Provinces such as Ontario, Alberta, and Quebec have renewable fuel blending requirements, RNG injection targets, and funding programs to encourage clean energy adoption in transportation, heating, and waste-to-energy projects.

Compliance and reporting requirements

To meet regulatory obligations or qualify for incentives, RNG producers must adhere to specific compliance and reporting standards, including:

• Documentation standards: RNG producers must maintain detailed documentation on feedstock sourcing, production processes, and lifecycle emissions to demonstrate compliance. This also includes accurate tracking of RNG distribution, end-use, and Renewable Identification Number (RIN) generation.

• Third-party verification: Many regulatory programs such as California's LCFS and cap-and-trade systems require third-party audits. These audits verify emissions reductions or other compliance requirements, and it can also make RNG fuels more credible to buyers.

See how RNG fits into your climate strategy

RNG offers significant potential for organizations to reduce greenhouse gas emissions and achieve other environmental and economic goals, but it can be hard to navigate this new market alone.  

Anew is one of the largest independent RNG marketers globally, and we can help you more easily reach your climate targets with an end-to-end RNG solution, streamlining the path from production to offtake.  

For RNG producers, Anew helps you navigate regulations, bring RNG to market, and grow revenue. For RNG buyers, we help you secure a reliable RNG supply and gain a better understanding of this market.

Contact our climate experts today to cut through the complexity and see how RNG can benefit you.

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