The gas transmission system injects gas into distribution systems at gas gates. Retailers trading at a gate each submit their best estimate of their customers’ gas consumption in a month. Based on the injection and submissions the allocation agent allocates gas to each retailer. Every month has three allocations. The initial allocation is performed 5 business days after the consumption month. The interim allocation is performed 4 months after the consumption month and the final allocation is performed 12 months after the consumption month. 

The difference between the volume injected at a gate and the volume retailers submit is unaccounted for gas (UFG). 

Unaccounted for gas typically arises from retailer estimation error, metering or energy conversion inaccuracies, or technical losses on the system. The cost of unaccounted for gas is spread across all retailers depending on their customer mix. 

Rolling 12-month UFG using final and interim data 

This chart shows a 12-month rolling figure for both the total amount of UFG in TJ (the columns) and UFG as a percentage of injection (the line). The data used comes from interim and final allocations. 

Monthly UFG using interim and final data

This chart shows the monthly UFG in TJ (the columns) and as a percentage of injection (the line). The data used comes from interim and final allocations.