This report analyses the legal framework for marketing of renewable energy produced at a wastewater treatment plant for three different countries (Germany, France, Denmark). Looking at the energy types of electricity (for self-supply or grid supply), heat and biomethane, the report describes taxes, fees, levies, and subsidy schemes which directly affect the potential revenues of the WWTP operator. The analysis shows that there are large differences between the countries that have a decisive impact on the economic attractiveness of the different options. While electricity use for self-supply is favored in case of high purchase costs for grid electricity (e.g. Germany), subsidy schemes for grid supply can also make this option economically relevant. In all countries, the grid injection of biomethane is a viable option which will be increasingly attractive for WWTP operators in the future. Reliable legal frameworks are required to offer stability for longterm investment at WWTP level, which is today often not the case due to the dynamic nature of the energy markets and policies.