Renewable natural gas (RNG) offers the tantalizing promise of carbon-negative methane derived from waste streams. Recognizing this, states and corporations have set ambitious targets for RNG. Combined with state and federal subsidies, RNG production has boomed over the past five years. What is the potential scale of future RNG development? Can industry bring down costs? What sources of RNG are prevalent today? Where will we source RNG in 5 to 10 years?