The aim of the project is to contribute to understanding of the effects of the Tariff Network Code (TAR NC) implementation in the Energy Community Contracting Parties. Calculations using the methodology set as counterfactual in the TAR NC (capacity weighted distance) were prepared for Serbia and Ukraine, in close cooperation with local Regulatory Authorities. At the end of the project, results were presented to tariff regulation experts from other Energy Community Contracting Parties. Proper understanding of the possibilities delivered by the TAR NC should help other regulators from these countries to prepare for the legislative and regulatory challenges ahead in the field of gas transmission tariff setting.