In Italy, if biomethane/RNG is not certified as "sustainable", it is not entitled to economic incentives. But how to obtain the certification of sustainability? First of all, it is necessary to ensure that it has not been produced using raw materials which derive from soils with a high carbon content, such as forests or peatlands. The most delicate aspect, however, concerns greenhouse gas emissions: the biomethane must be produced by reducing emissions by at least 65% in relation to the reference fossil fuel. The parameters for the calculation are contained in the UNI/TS 11567 standard. How to unravel these parameters and not make mistakes in the calculation? We asked the CIB - Consorzio Italliano Biogas.