For non-half-hourly metered supplies, the NHHDC determines the consumption by calculating the advance (the difference between the last two meter reads, this is annualised to produce an annual advance (AA), this being the data the supplier will pay on).
The NHHDC is also responsible determining the estimated annual consumption (EAC), which is a forecast for a year ahead. The EAC is initially provided by the supplier, and thereafter forecast based on actual meter readings.
Data from the DC (EAC/ AA's) is provided to the non half hourly data aggregator, which aggregates the individual values provided into a single figure split in a number of ways e.g. geographically, geographically & supplier or supplier. This aggregated data is then provided to the Central Systems, maintained by Elexon, to determine the value of energy which has been used by suppliers so that they are able to settle with the distribution network which generated the energy. The process is known as balancing and settlement and falls under the balancing and settlement code (BSC).
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