Efforts to decarbonize the economy require a mix of thoughtful and effective policies. In the case of natural gas utilities, they have two options: decrease gas consumption or decarbonize the pipeline. In the case of the former, some of that decrease may arise from electrification. Decarbonizing the pipeline, however, offers a real alternative to fuel switching. This ICF white paper reviews the design principles of a Renewable Gas Standard, one of the main policy mechanisms that can help gas utilities cost-effectively reduce carbon emissions.