Renewable natural gas is methane collected from landfills, dairy and hog manure digesters, wastewater plants and food waste, cleaned to pipeline quality and injected into the natural gas grid. At the pump it is identical to fossil CNG. 69% of public CNG stations (462 of 674) report dispensing it. The badge means the station has RNG in its supply, usually by contract, not that every molecule you buy was made from waste.
What it is and where it comes from
Anywhere organic matter rots without oxygen, bacteria make biogas: roughly half methane, half carbon dioxide, with traces of hydrogen sulfide and water. Landfills make it for decades. Dairy lagoons and hog farms make it constantly. Wastewater digesters and food-waste digesters make it on purpose. Left alone, that methane leaks to the atmosphere, where it traps far more heat than the CO2 it would become if burned.
An RNG project captures the biogas, strips the CO2, sulfur and water, compresses the result to pipeline pressure and injects it into the same grid that serves every CNG station. The producer sells the physical gas at market price and, separately, sells the environmental attributes of that gas to whoever wants to claim them, typically a fuel supplier serving natural gas vehicles.
| Source | Share of U.S. RNG supply | Notes |
|---|---|---|
| Landfills | The largest share | Big, steady, decades-long output; moderate carbon benefit |
| Dairy and swine manure | Fast-growing | Smaller volumes but the strongest carbon benefit, because the methane would otherwise vent from open lagoons |
| Wastewater treatment | Small | Many plants already burn biogas for heat; upgrading to RNG is a newer step |
| Food and agricultural waste | Small | Purpose-built digesters |
What the RNG badge on a listing means
The DOE station record has a yes/no field for renewable natural gas. When it is yes, the station has RNG in its supply, and the listing on this site shows the green badge. Three things it does not tell you:
- The share. A station can be 100 percent RNG by contract or a blend. The DOE does not record the percentage.
- The physical molecules. Because RNG is injected into a shared pipeline, the gas in your cylinder is grid gas. What the station bought is the right to claim the RNG that entered the pipe somewhere else. This is the same book-and-claim system used for renewable electricity.
- The fill. Nothing about fueling changes. Same pressure, same nozzle, same price at the dispenser unless the operator chooses to price it differently.
For an individual driver the badge is a footnote. For a fleet it decides whether fuel purchases can be reported as low-carbon under a customer's or a regulator's program.
The carbon math
Burning RNG releases CO2 just like fossil gas. The benefit comes upstream: capturing methane that would otherwise have escaped. Under California's Low Carbon Fuel Standard, which scores fuels on lifecycle grams of CO2-equivalent per megajoule, fossil CNG scores a little below diesel, landfill RNG scores far below it, and dairy RNG scores negative, because the avoided methane outweighs the CO2 from burning it. That negative score is why some fleets report their natural gas trucks as carbon-negative, and it is also the part of the accounting that is most argued over, since it depends on assuming the manure lagoon would otherwise have vented.
Industry trade groups report that most natural gas used in U.S. vehicles is now RNG; in California, where the credits are richest, the share has been reported above 90 percent for on-road use. The 69% of public stations carrying the badge on this site is consistent with that.
Credits and who benefits
- Federal RINs. RNG used as vehicle fuel generates credits under the Renewable Fuel Standard, sold by the producer or fuel supplier.
- California LCFS and similar programs in Oregon and Washington generate additional credits based on the carbon score.
- The station price. Those credits accrue to the supplier, not usually to the driver at the pump, though fleet contracts sometimes pass a share through as a lower price.
- Fleet reporting. Shippers increasingly ask carriers for scope-3 emissions; an RNG-supplied CNG fleet has a documented low number to report.
Whether a particular station's RNG is dairy or landfill, and what share, is a question for the operator. The networks page shows the RNG share of each operator's stations as recorded by DOE, and the state pages flag every station that carries it.
FAQ
What is renewable natural gas?
Methane captured from landfills, manure digesters, wastewater plants and food waste, cleaned to pipeline quality and injected into the natural gas grid. It is chemically the same as fossil natural gas and is used in the same vehicles and stations.
Is RNG really carbon-negative?
Under lifecycle accounting such as California's Low Carbon Fuel Standard, RNG from dairy manure can score below zero because capturing the methane avoids more warming than burning it causes. Landfill RNG scores low but positive. The negative score depends on assumptions about what would otherwise have happened to the manure, which is why it is debated.
Does the RNG badge mean the gas I buy is renewable?
It means the station has renewable natural gas in its supply, usually by contract. Because RNG is injected into a shared pipeline, the physical gas in your tank is grid gas; the station has bought the environmental attributes of RNG that entered the pipe elsewhere, the same way green electricity is sold.
Does RNG cost more at the pump?
Usually not. The credits that make RNG valuable go to the producer and fuel supplier rather than being charged at the dispenser. Some fleet contracts pass a share of that value through as a lower price.
How many CNG stations sell RNG?
About seven in ten public CNG stations in the DOE database report dispensing renewable natural gas. The exact count is shown at the top of this page and refreshed weekly.
Find a station
Every public CNG station, with the badges this guide explains.