System Frequency
This page holds the historic system frequency data for Great Britain at a 1 second resolution. It is the role of the National Grid ESO to keep the system frequency at 50 Hz, with a statutory limit of 0.5 Hz above or below this value.
Time values are all given in Greenwich Mean Time (GMT) starting January 2020.
NOTE: Due to the size and format of these files, to view the data, please download the CSV file and open it with Notepad++ for complete document loading.
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143 Data Files
| Name | Format | Last Changed Sort ascending | Download | Explore |
|---|---|---|---|---|
| November 2025 – Historic Frequency Data | CSV | Download (CSV) | view | |
| October 2025 – Historic Frequency Data | CSV | Download (CSV) | view | |
| September 2025 – Historic Frequency Data | CSV | Download (CSV) | view | |
| August 2025 – Historic Frequency Data | CSV | Download (CSV) | view | |
| July 2025 – Historic Frequency Data | CSV | Download (CSV) | view | |
| June 2025 – Historic Frequency Data | CSV | Download (CSV) | view | |
| May 2025 – Historic Frequency Data | CSV | Download (CSV) | view | |
| April 2025 – Historic Frequency Data | CSV | Download (CSV) | view | |
| March 2025 – Historic Frequency Data | CSV | Download (CSV) | view | |
| February 2025 – Historic Frequency Data | CSV | Download (CSV) | view |
Additional Information
| Field | Value |
|---|---|
| Creator | National Grid Electricity System Operator |
| Date Created | November 5, 2019 at 11:50 AM (UTC+00:00) |
| Source | National Grid Electricity System Operator |
| Rights | NESO Open Data Licence |
| Update Frequency | Monthly |
cURL integration
# Get a list of dataset's resources
curl -L -s https://api.neso.energy/api/3/action/datapackage_show?id=system-frequency-data | grep path
# Get resources
curl -L https://api.neso.energy/dataset/cb1cc925-ecd8-4406-b021-3a3f368196e1/resource/2ddaf963-191a-43c3-bb3b-286de31508ee/download/fnew-2025-11.csv
curl -L https://api.neso.energy/dataset/cb1cc925-ecd8-4406-b021-3a3f368196e1/resource/288eba29-3ea0-4a93-bc7f-995c98473294/download/fnew-2025-10.csv
curl -L https://api.neso.energy/dataset/cb1cc925-ecd8-4406-b021-3a3f368196e1/resource/5b1ae652-c0d5-4853-b46f-6af414b487fd/download/fnew-2025-9.csv
curl -L https://api.neso.energy/dataset/cb1cc925-ecd8-4406-b021-3a3f368196e1/resource/b511a71e-15dc-4bb4-a4e1-dcb881363a85/download/fnew-2025-8.csv
curl -L https://api.neso.energy/dataset/cb1cc925-ecd8-4406-b021-3a3f368196e1/resource/a3cbf8d1-8327-4c80-82ef-a7a31820ec72/download/fnew-2025-7.csv
curl -L https://api.neso.energy/dataset/cb1cc925-ecd8-4406-b021-3a3f368196e1/resource/8ac51432-f0c0-42e7-836e-247a030c91b9/download/fnew-2025-6.csv
curl -L https://api.neso.energy/dataset/cb1cc925-ecd8-4406-b021-3a3f368196e1/resource/2122c101-fad5-4989-9814-728572d510e0/download/fnew-2025-5.csv
curl -L https://api.neso.energy/dataset/cb1cc925-ecd8-4406-b021-3a3f368196e1/resource/f81823de-ac73-48d4-8b4f-d2c871e5702e/download/fnew-2025-4.csv
curl -L https://api.neso.energy/dataset/cb1cc925-ecd8-4406-b021-3a3f368196e1/resource/6437cf1d-8517-42dc-9086-e386df5065d5/download/fnew-2025-3.csv
curl -L https://api.neso.energy/dataset/cb1cc925-ecd8-4406-b021-3a3f368196e1/resource/ec60c750-b4e4-4328-a693-7b562467b175/download/fnew-2025-2.csv