Per Wikipedia (emphasis added), "Biogas [RNG] is considered to be a renewable resource because its production-and-use cycle is continuous, and it [biogas] generates no net carbon dioxide. As the organic material grows, it is converted and used. It then regrows in a continually repeating cycle. From a carbon perspective, as much carbon dioxide is absorbed from the atmosphere in the growth of the primary bio-resource as is released, when the material is ultimately converted to energy."

As defined by the U.S. Department of Energy "Renewable Natural Gas (RNG) is a pipeline-quality gas that is fully interchangeable with conventional natural gas and thus can be used in natural gas vehicles. RNG is essentially biogas (the gaseous product of the decomposition of organic matter) that has been processed to purity standards."