What Is Renewable Natural Gas? Definition, Uses, Pros, Cons

Renewable natural gas is biogas that has been cleaned and upgraded to match the quality of conventional natural gas from underground reserves. You produce it by capturing methane from organic waste sources like landfills, farms, and wastewater plants, then removing impurities until what remains is nearly pure methane. The result is a fuel you can inject directly into existing gas pipelines or use to power vehicles without modifying infrastructure.

This article explains how RNG works in practical terms. You'll learn where it comes from, how businesses use it for heating and transportation, and what makes it different from fossil gas. We'll cover the real benefits and limitations you need to know, compare performance metrics, and outline what matters most when planning an RNG project. Whether you're evaluating RNG for your operation or designing systems for clients, you'll get the facts without the marketing spin.

Why renewable natural gas matters

You face a pressing challenge with methane emissions from organic waste. Landfills, farms, and wastewater facilities release methane directly into the atmosphere, and this gas traps 86 times more heat than CO2 over a 20-year period. When you capture and convert this methane into renewable natural gas, you stop those emissions at the source while creating a fuel that works in existing infrastructure. Your heating systems, pipelines, and vehicle fleets require no modifications to run on RNG instead of fossil gas.

The infrastructure advantage

RNG solves what is renewable natural gas's biggest practical advantage: immediate deployment without capital-intensive retrofits. You inject purified biomethane into the same pipelines that carry conventional gas, and your customers use it through the same meters, burners, and appliances they already own. This compatibility means you can displace fossil fuels today rather than waiting years for new energy systems to be built out. The gas grid becomes a delivery network for renewable energy, turning a liability (waste methane) into a revenue stream while meeting decarbonization targets your clients demand.

RNG projects create measurable emission reductions you can verify and monetize through carbon credits while addressing regulatory pressure to reduce methane from waste operations.

How to use renewable natural gas in practice

You deploy RNG through three primary channels that leverage existing infrastructure and equipment. Pipeline injection represents the most common approach: you upgrade biogas to pipeline quality (typically 98% methane or higher), then inject it into the natural gas distribution network where it flows to residential, commercial, and industrial customers. These end users burn RNG in their existing furnaces, water heaters, and industrial boilers without any modifications to their equipment. Your clients simply receive renewable fuel through the same meter connection they've always used.

Pipeline injection and distribution

Your processing facility connects directly to a natural gas transmission or distribution pipeline after meeting the grid operator's quality specifications. You need to match pressure requirements (usually 200 to 1,000 psi depending on the pipeline), heating value (typically 967 to 1,050 BTU per cubic foot), and strict limits on contaminants like hydrogen sulfide, oxygen, and water vapor. Once injected, the gas mixes with conventional supply and reaches customers who use it for space heating, cooking, and manufacturing processes. Local utilities often purchase this gas under long-term contracts with premium pricing that reflects its renewable attributes and carbon reduction value.

Pipeline injection lets you monetize RNG immediately through existing commercial relationships with gas utilities while earning renewable energy credits that stack on top of commodity gas prices.

Transportation fuel applications

You compress or liquefy RNG to create vehicle fuel that directly replaces diesel or gasoline in fleet operations. Heavy-duty trucks, refuse haulers, and transit buses run on compressed natural gas (CNG) stations where RNG provides the same range and performance as conventional natural gas but with carbon intensity reductions of 80% to 90%. Liquefied RNG works for long-haul trucking where weight and range matter most, offering diesel-equivalent energy density while qualifying for low-carbon fuel credits in regulated markets.

Key benefits and limitations of RNG

You gain immediate carbon reduction when you replace fossil gas with RNG because the methane you capture was already in the natural carbon cycle. Organic waste decomposes and releases methane whether you capture it or not, so converting that methane into fuel prevents atmospheric emissions while displacing fossil extraction. Your projects qualify for renewable energy credits and low-carbon fuel standards in many jurisdictions, creating revenue streams that stack on top of commodity gas pricing. These financial incentives often make what is renewable natural gas economically competitive with conventional supply despite higher production costs.

Economic and environmental advantages

RNG delivers proven carbon intensity reductions between 80% and 90% compared to diesel or conventional gas when you account for avoided methane emissions from waste sources. Your operation requires no infrastructure modifications because pipelines, compressors, and end-use equipment already handle methane. Production facilities built near waste sources create local jobs while reducing dependence on imported fossil fuels, and capturing methane from landfills or farms solves an environmental liability your clients face regardless of energy projects. Many waste operators pay you to take their biogas, inverting the traditional fuel supply cost structure.

RNG projects turn waste management costs into energy revenue while generating tradeable carbon credits that provide income certainty through long-term contracts.

Technical and operational constraints

Your feedstock supply determines project viability because you need consistent biogas volumes with predictable composition to maintain steady production. Intermittent waste streams force you to oversize equipment or accept capacity underutilization that hurts economics. Contaminant removal drives capital and operating costs higher than fossil gas extraction, particularly for siloxanes, hydrogen sulfide, and halogenated compounds that damage processing equipment if not removed. Equipment manufacturers often quote prices for standard configurations, but your actual costs rise when dealing with difficult feedstocks that require additional cleanup stages or specialized materials.

Smaller projects struggle with economies of scale because upgrading equipment carries minimum practical sizes below which per-unit costs become prohibitive. Your processing system needs to justify itself against the biogas volume available, and many potential sources produce too little gas to support dedicated upgrading infrastructure. Transportation costs limit how far you can economically move biogas before processing, confining projects to locations where waste sources sit near pipeline access or fuel demand centers.

RNG compared to conventional natural gas

You work with chemically identical fuel whether you burn RNG or fossil gas because both consist of methane molecules with the same molecular formula. Pipeline specifications require 95% to 98% methane purity for either source, and once upgraded, RNG delivers the same heating value (approximately 1,000 BTU per cubic foot), pressure characteristics, and combustion properties as conventional supply. Your equipment cannot distinguish between the two fuels, which means burners, engines, and appliances operate at identical efficiency levels regardless of which methane source feeds them.

Carbon and cost differences

RNG carries carbon intensity between negative 300 and positive 50 grams CO2e per megajoule, while fossil gas registers 75 to 90 grams per megajoule. This stems from avoided methane emissions when you capture biogas from waste. Production costs run $15 to $35 per million BTU versus $3 to $8 for conventional gas.

What is renewable natural gas delivers identical performance to fossil supply while cutting lifecycle emissions by 80% to 90% through waste-based methane capture.

Your RNG commands premium pricing over fossil supply because it generates tradeable credits under renewable fuel standards. Long-term contracts lock in these premiums for 10 to 20 years, offsetting higher production costs and making projects financially viable.

RNG project considerations for developers

You need to evaluate feedstock availability and composition before committing to equipment specifications because biogas characteristics directly determine your processing requirements and operating costs. Projects fail when developers underestimate the capital needed for contaminant removal or overestimate the consistent gas volumes a waste source will deliver. Site selection matters as much as technology choice: you want proximity to both your biogas source and either pipeline infrastructure or fuel demand centers, because moving raw biogas or finished RNG adds costs that erode project economics quickly.

Feedstock assessment and site selection

Your first step involves securing long-term feedstock commitments with documented gas composition data spanning at least 12 months to capture seasonal variations. Landfill gas typically contains 45% to 60% methane with high siloxane loads, while agricultural digesters produce 55% to 70% methane with lower contaminants but variable flow rates tied to farm operations. You conduct gas analysis for hydrogen sulfide, siloxanes, halogenated compounds, and oxygen levels because these drive your equipment selection and operating expense projections. Pipeline access within 5 miles of your processing site keeps interconnection costs manageable, though direct fuel sales to fleet customers can work when pipeline injection proves impractical.

Understanding what is renewable natural gas production requires matching your cleanup technology to actual feedstock chemistry rather than relying on vendor assumptions about typical biogas composition.

Processing technology and specifications

You select upgrading technology based on scale and gas quality requirements your project must meet. Membrane systems work efficiently above 100 standard cubic feet per minute with lower capital costs but higher methane slip, while pressure swing adsorption delivers superior methane recovery at smaller scales where every molecule counts toward project returns. Your equipment must meet pipeline specifications for methane purity, heating value, and contaminant limits, with typical targets of 98% methane, less than 10 ppm oxygen, and dewpoint below negative 20 degrees Fahrenheit at pipeline pressure.

Final thoughts

You now understand what is renewable natural gas delivers in practical terms: pipeline-quality fuel from waste sources that works in existing infrastructure while cutting carbon emissions by 80% to 90%. Your projects succeed when you match processing technology to actual feedstock characteristics rather than relying on theoretical performance claims from equipment vendors. Site economics depend on securing consistent biogas volumes, minimizing transportation distances, and accessing either pipeline networks or direct fuel customers who value renewable attributes enough to pay premium pricing over conventional gas supply.

Equipment selection drives your operating costs and methane recovery rates more than any other factor in project viability. 99pt5's proven BioGas processing systems with guaranteed performance specifications give you the certainty your project financing and client contracts require.