System operations
Unaccounted for gas (UAG)
Unaccounted for gas (UAG) is gas that is lost, or otherwise not accounted for, on the National Transmission System (NTS). National Gas investigates the causes of UAG, which is one of the components of NTS Shrinkage.
Gas unaccounted for due to metering errors
Gas that is unaccounted for in the National Transmission System (NTS) is likely to be the result of a data or metering error. That makes it a complex component of shrinkage to investigate. Identifying the specific potential causes of UAG includes looking at the mechanical behaviour of high-pressure metering systems, as well as statistical variations in their operation.
Daily UAG data
We publish daily UAG data on each week. Due to the process of energy data close-out, the most recent values are subject to change and are available to download:
UAG reports
We regularly report on our activity to investigate the potential causes of UAG. These reports cover the latest UAG trends and provide updates on our data analysis and meter validation activities. Take a look at our most recent UAG Report, as well as previous reports