Unaccounted for gas in natural gas transmission networks: Prediction model and analysis of the solutions

In this paper the authors investigate the UAG sources and evaluate the criticalities related to UAG estimation-prediction, besides the possible actions aimed at reducing UAG quantity in different NG transmission networks. To this purpose, the authors investigate the UAG in some relevant NG transmission networks, statistically analyzing annual and monthly trends of UAG and evidence UAG sources, with particular reference to the influence of the uncertainty of the measuring plants. In fact, inaccurate measurements can be responsible of large UAG, with potentially significant economic losses for all players in the system. Finally, the authors point out that the main UAG sources are related to some systematic measurement errors associated to climatic conditions and propose a simplified model to predict UAG value.