A methodology was developed to determine the location and biomethane potential of on-farm biomass feedstocks and furthermore, the quantity of this biomass situated away from an existing gas grid network. The development of decentralised systems which can be integrated with large industry in such locations offers a potential alternative deployment opportunity to centralised gas grid injection. The total biomethane resource from all on-farm feedstocks in a chosen case country (Ireland) was estimated at 67 PJ. Thematic maps were developed to show the quantity of each on-farm feedstock in different regions of Ireland and their distance from the existing gas network. Approximately 17% of the on-farm biomethane resource in Ireland, though in excess of 15 km from the grid, was within a 15 km radius of a large energy user. Two large energy users were presented as case studies, of which their entire heating demand could be met by the on-farm biomethane resource within a 2.5 km radius of each site. Coupling decentralised biomass with large industry users can potentially offer an alternative energy management strategy.