Upgraded biogas injected into a natural gas grid may provide considerable increase of renewable energy share within the natural gas-fired systems. The goal of the study is to determine the costs of biomethane produced in distributed biogas plants and injected into the natural gas grid. The analyzed system includes biogas upgrading and transport to the natural gas pipeline including the infrastructure. The total costs of biomethane production for 3 different scenarios and 5 biogas upgrading methods are determined. The results show that under the most favourable scenario the injected biomethane is approximately 19% more expensive than the natural gas.