Rio de Janeiro has taken a decisive step toward energy transition by creating a package of tax and regulatory incentives for clean fuels, making biogas, biomethane, and B100 biodiesel viable alternatives to natural gas and fossil diesel. Through State Law nº 9,635/2022 and Decrees nº 48,972/2024 and 48,053/2022, the state reduced the ICMS tax base for biogas and biomethane, aligning their taxation with that of natural gas, and established special tax treatment for pure biodiesel. This decision created a stable and competitive regulatory environment, which is already stimulating private investment and expanding the use of low-carbon energy in transportation and industrial processes. Currently, Rio has 12 biogas and biomethane plants in operation, which have already generated R$ 731 million in ICMS revenue and 2,300 direct and indirect jobs, with an estimated R$ 1.2 billion in new investments. By aligning tax incentives, grid infrastructure, and industrial demand, the state demonstrates how traditional economic instruments can accelerate decarbonization, generate local jobs, and transform waste into clean energy.