RNG can be produced from various sources, including landfills, wastewater treatment plants, and livestock operations. Landfills are a significant source of RNG, as the decomposition of waste in landfills produces a gas rich in methane. Wastewater treatment plants also produce RNG, as the treatment process involves decomposing organic matter to produce methane-rich gas. Livestock operations, such as dairy and pig farms, can also produce RNG, as the manure from these operations can produce biogas. The production of RNG from these sources involves using anaerobic digesters, which are systems that break down organic matter without oxygen to produce biogas. The biogas is then upgraded to produce RNG, which can be used as a replacement for traditional natural gas.