A Decision Support Tool (DST) has been developed that will aid Distribution Service Operators (DSOs) in their decision making process on which investments to make in the gas distribution grid in order to facilitate the use of biogas. The DST considers both the conversion of biogas to electricity as well as upgrading the biogas to green gas and consequently injecting it into the gas grid. Based on a starting configuration - i.e. a gas grid, gas consumers connected to this grid, and biomass locations -, in combination with several building blocks - e.g. a digester installation, an upgrading plant, and a CHP installation -, the tool generates several solutions to utilize the biomass. The DST generates solutions and determines for each solution two performance criteria: CO2 emission reduction and costs. Showing these solutions, gives the DSOs insight in the available options and which trade-offs can be made. A case study has been performed for the gas grid of the Dutch municipality of Zutphen. This case study showed that cost-wise there is a preference for centralization, i.e. digesting biomass at a central location and upgrading the biogas at a central location to green gas. Furthermore, conversion of biogas to electricity led to the highest CO2 emission reduction, but also to the highest cost. Furthermore, the case study showed that the DST basically works, and that it is a good way to explore the possible investment options. The tool however needs further improvements. For instance, more performance indicators (e.g. energy usage and reliability) will be included. Furthermore, the interaction with the electricity grid will be incorporated and multiple gas qualities in the distribution grid will be introduced. Also more boundary conditions should be added to the DST, for instance taking the topology of the area into account when laying pipelines