Treatment of Volume Notifications on the ‘short’ clock change day 26 March 2023
UK time changes on Sunday 26 March 2023 from Greenwich Mean Time (GMT)/Coordinated Universal Time (UTC) to British Summer Time (BST) at 01:00 (GMT). This will result in a ‘short’ day as the clocks go forward an hour.
Which Settlement Periods are affected by this?
On a ‘short’ clock change day, there are only 46 Settlement Periods instead of the normal 48:
- Settlement Periods one to two inclusive on 26 March 2023 will begin as normal at 00:00 (GMT) and 00:30 (GMT) respectively
- At 01:00 (GMT), the clocks will change to BST so instead of Settlement Period three beginning at 01:00 (GMT), it will begin at 02:00 (BST
- Settlement Period four will begin at 02:30 (BST) and so on until Settlement Period 46 begins at 23:30 (BST).
What happens if I submit a contract notification which includes both the clock change day and normal days?
If you submit a contract notification which includes the clock change day and normal, non-clock change days, Energy Contract Volume Aggregation Agent (ECVAA) default rules apply.
The notified volumes corresponding to Settlement Periods three and four will be removed on the clock change day. Notified volumes for the remaining Settlement Periods on the clock change day will all be used for the Settlement Period, two Settlement Periods earlier than the one they were originally notified for.
What happens if I submit a contract notification for the clock change day alone?
If you submit a contract notification for the clock change day alone, the Settlement Periods in the contract notification should be numbered from 1 to 46. Please note that contract notifications for the clock change day must contain the correct number of Settlement Periods as no defaulting rules will be applied to these notifications.
Will the content of any of the reports I receive be different?
Yes, the ECVAA Notification Report (ECVAA-I014) for 26 March will only contain 46 Settlement Periods and will include the effect of any defaulting rules applied to multi-day notifications.
The ECVAA Forward Contract Report (ECVAA-I022) for 26 March will show a representation of the original notifications submitted.
Do I need to take any further action?
No, however if you have any questions please contact the BSC Service Desk.
Where can I find previous Circulars?
See the current and previous circulars on our subscription page for an archive.