Power NI made a system change on 1 November 2022 that alters how its bills present charges when a price change applies partway through a billing period. The supplier says the change means that when it applies a price change, it will display separate lines on the bill showing the charges for units and standing charges, for before and after the price change1.
"From 1 November we made a system change that means when we apply a price change, we will display separate lines on your bill showing the charges for units and standing charges, for before and after the price change."
The process behind those lines is proration. Where a bill straddles a pricing change and more than one rate applies during the billing period, Power NI calculates an average of daily consumption. That daily figure is then used to work out the number of days before and after the price change, and the total bill units are split accordingly. Each set of units is multiplied by the unit rate that applied in that period, and both totals appear on the bill1.
Power NI's own worked example uses a bill period of 01/10/2022 to 31/12/2022 with a price change on 01/11/2022. Total bill units divided by total bill days gives units per day; multiplying that by the days in each period gives the units before and after the change, which are then charged at the respective unit rates1.
| Element of the example | Figure |
|---|---|
| Bill period | 01/10/2022 to 31/12/2022 |
| Price change date | 01/11/2022 |
The supplier also addresses overlapping bill dates. Where one bill runs to a date and the next bill begins on that same date, Power NI states this is the layout of the bill rather than a double charge, and that the householder will only be billed once for that date1. On meter readings, Power NI says there is no need to submit a meter read outside of the meter reading window1.
Why it matters for households
A bill that covers a price change has, until now, been difficult to check from the document alone, because a single set of units and a single standing charge line can conceal two different rates. Showing the split makes the arithmetic on the bill verifiable against the unit rates and standing charges that applied in each part of the period, and it separates the two components that make up the total: the standing charge and the units used.
For a household tracking its own energy independence, the practical effect is that a bill spanning a tariff change can be reconciled line by line rather than taken on trust. The change is presentational: it does not alter how much is charged, only how the charge is displayed. The underlying method, averaging daily consumption across the period and allocating it by days, remains the same, and it is the method rather than the layout that determines the split between the two rates. Households wanting to check a bill against meter readings will still find the reading an energy bill guidance relevant, and the wider context of billing in Northern Ireland differs from Great Britain.
What happens next
No further dated steps are given. Power NI states the system change took effect from 1 November 2022 and applies when a price change is applied1. No date has been reported for any subsequent change to the bill layout.