What are the leading biomass and biogas energy operator companies in the United States that develop, manage, and operate renewable energy facilities using organic waste, landfill gas, and agricultural residues? These companies focus on converting waste materials into renewable electricity and renewable natural gas (RNG). The question aims to identify major U.S. players based on operational scale, technology adoption, and project portfolio. It also highlights their role in reducing carbon emissions and supporting the circular economy through waste-to-energy solutions.