21 AUGUST
NEW ZEALAND GAZETTE
2499

Regulation 19

Use of estimated information in certain cases

If any information for Regulations 17 or 18 is not available, the pipeline owner may use estimated information for that purpose and, in that case, (i) identify the information that has been compiled using estimated information; and (ii) state the methodology used to calculate the estimated information.

1. UFG %:

   In determining the unaccounted-for gas, the sales component includes a portion which is unbilled gas. This portion involves a small estimate for the number of days during the financial year where the billing reading dates do not correspond with the sales gate reading dates. This generally only affects domestic customers’ sales, the estimate being based on the daily average usage of the preceding billing period. A computer program is run monthly to compute this unbilled gas, for the preceding three months’ periods, such that the oldest period then contains the smallest error.

   For 1998-1999, there were problems in running this program, and some months contained suspect results. These periods of suspect data have been excluded from the UFG% calculations.

   This data has been shown by a ~.

   For 1999-2000, the reports referred to above were produced for the first six months only. After this time, only data of billed sales was available from retailers. A determination of UFG was made using the full year’s billed data. This produced a few anomalies, so for these systems, the previous method was used up until the data was no longer available. Also, as above, any periods of suyspect data have been excluded from the UFG% calculations.

   This data has also been shown by a ~.

2. Unplanned Interruption Measure:

   The customer-hours lost have been estimated in a number of ways:

   (i) On systems where the number of customers affected and the length of the interruption have been recorded, but are not available for the full financial year, this data has been extrapolated such that it would then cover the full 12 month period. As the specific system involved has not been recorded, the estimated customer-hours lost in total has been apportioned across system(s) indicated by the local engineer as being the contributing system(s), the apportionment being on a pro-rata basis by system length.

   This data has been shown by a #.

   (ii) On systems where the number of customers affected has been recorded, but the length of each interruption has not been recorded, the local engineer has estimated the average length of the interruptions. The specific system involved is recorded.

   This data has been shown by a ^.

   (iii) On systems where the number of customers affected has been recorded, but the length of each interruption has not been recorded, the local engineer has estimated the average length of the interruptions. As the specific system involved has not been recorded, the estimated customer-hours lost in total has been apportioned across system(s) indicated by the local engineer as being the contributing system(s), the apportionment being on a pro-rata basis by system length.

   This data has been shown by a *.

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