Short Term Operating Reserve (STOR) are energy balancing reserves National Grid calls upon from STOR providers during STOR Availability Windows (SAW). National Grid splits the year in a number of seasons and specifies the period in each day (working and non-working days) where STOR providers can be called upon to deliver STOR; this period is known as the STOR Availability Window (SAW).
STOR Availability Window – 1 April 2025 to 1 April 2026
The table below displays the STOR Availability Window for the period 1 April 2025 to 1 April 2026. Non-Working Days (NWD) apply to all Sundays and all Bank Holidays and Public Holidays in England and Wales.
| STOR AVAILAIBILITY DATES | WORKING DAY | NON-WORKING DAY | |||||
| SEASON YEAR | SEASON NUMBER | FROM DATE | TO DATE | START TIME [GMT] | END TIME [GMT] | START TIME [GMT] | END TIME [GMT] |
| 2025-2025 | 1 | 01/04/2025 04:00 | 28/04/2025 04:00 | 05:00 | 12:00 | 09:00 | 13:00 |
| 2025-2025 | 1 | 01/04/2025 04:00 | 28/04/2024 04:00 | 18:00 | 21:00 | 16:30 | 21:00 |
| 2025-2025 | 2 | 28/04/2025 04:00 | 18/08/2025 04:00 | 05:30 | 13:00 | 09:30 | 12:30 |
| 2025-2025 | 2 | 28/04/2025 04:00 | 18/08/2025 04:00 | 15:00 | 21:00 | 16:30 | 21:00 |
| 2025-2025 | 3 | 18/08/2025 04:00 | 22/09/2025 04:00 | 05:30 | 12:00 | 09:30 | 11:30 |
| 2025-2025 | 3 | 18/08/2024 04:00 | 22/09/2024 04:00 | 15:00 | 21:00 | 16:30 | 21:00 |
| 2025-2025 | 4 | 22/09/2025 04:00 | 20/10/2025 04:00 | 05:00 | 12:00 | 09:30 | 12:00 |
| 2025-2025 | 4 | 22/09/2025 04:00 | 20/10/2025 04:00 | 16:00 | 21:00 | 16:30 | 21:00 |
| 2025-2026 | 5 | 20/10/2025 04:00 | 18/01/2026 05:00 | 06:00 | 13:00 | 10:30 | 13:30 |
| 2025-2026 | 5 | 20/10/2025 04:00 | 19/01/2026 05:00 | 16:00 | 20:30 | 16:00 | 19:30 |
| 2026-2026 | 6 | 19/01/2026 05:00 | 01/04/2026 04:00 | 06:00 | 13:00 | 10:30 | 13:00 |
| 2026-2026 | 6 | 19/01/2026 05:00 | 01/04/2026 04:00 | 16:30 | 20:30 | 16:30 | 20:00 |
Latest STOR Availability Window – CSV files
Previous STOR Availability Window – CSV files