Is the grid in balance
Electricity cannot be stored on the network, so generation has to match demand every second of the day. Frequency is the evidence that it does - and temperature is the biggest reason demand moves in the first place.
System frequency · target 50 Hz
50.103Hz
Balanced · +0.103 Hz from target
Slightly above 50 Hz, which means marginally more generation than demand right now.
Within normal range
100.0%
Of the last hour, inside ±0.2 Hz
Temperature
15.2°C
+2.2°C vs the seasonal average
6 October
Normal for the date
11.1–15.0°C
Today is outside this range, so demand will be unusual too
Frequency over the last hour
Sampled every fifteen seconds. The grid is held as close to 50 Hz as possible; ±0.2 Hz is routine.
View as table
| Time | Frequency (Hz) | From target |
|---|---|---|
| 00:48 | 49.893 | −0.107 |
| 00:49 | 49.888 | −0.112 |
| 00:50 | 49.889 | −0.111 |
| 00:51 | 49.901 | −0.099 |
| 00:52 | 49.901 | −0.099 |
| 00:53 | 49.924 | −0.076 |
| 00:54 | 49.904 | −0.096 |
| 00:55 | 49.894 | −0.106 |
| 00:56 | 49.911 | −0.089 |
| 00:57 | 49.928 | −0.072 |
| 00:58 | 49.964 | −0.036 |
| 00:59 | 49.980 | −0.020 |
| 01:00 | 49.983 | −0.017 |
| 01:01 | 49.880 | −0.120 |
| 01:02 | 49.865 | −0.135 |
| 01:03 | 49.880 | −0.120 |
| 01:04 | 49.880 | −0.120 |
| 01:05 | 49.873 | −0.127 |
| 01:06 | 49.855 | −0.145 |
| 01:07 | 49.877 | −0.123 |
| 01:08 | 49.883 | −0.117 |
| 01:09 | 49.869 | −0.131 |
| 01:10 | 49.883 | −0.117 |
| 01:11 | 49.880 | −0.120 |
| 01:12 | 49.886 | −0.114 |
| 01:13 | 49.892 | −0.108 |
| 01:14 | 49.888 | −0.112 |
| 01:15 | 49.895 | −0.105 |
| 01:16 | 49.919 | −0.081 |
| 01:17 | 49.933 | −0.067 |
| 01:18 | 49.957 | −0.043 |
| 01:19 | 49.971 | −0.029 |
| 01:20 | 50.016 | +0.016 |
| 01:21 | 50.025 | +0.025 |
| 01:22 | 50.029 | +0.029 |
| 01:23 | 50.017 | +0.017 |
| 01:24 | 50.022 | +0.022 |
| 01:25 | 50.024 | +0.024 |
| 01:26 | 50.020 | +0.020 |
| 01:27 | 50.025 | +0.025 |
| 01:28 | 50.028 | +0.028 |
| 01:29 | 50.037 | +0.037 |
| 01:30 | 50.113 | +0.113 |
| 01:31 | 49.964 | −0.036 |
| 01:32 | 49.975 | −0.025 |
| 01:33 | 49.949 | −0.051 |
| 01:34 | 49.945 | −0.055 |
| 01:35 | 49.968 | −0.032 |
| 01:36 | 50.058 | +0.058 |
| 01:37 | 50.039 | +0.039 |
| 01:38 | 50.039 | +0.039 |
| 01:39 | 50.043 | +0.043 |
| 01:40 | 50.056 | +0.056 |
| 01:41 | 50.081 | +0.081 |
| 01:42 | 50.086 | +0.086 |
| 01:43 | 50.112 | +0.112 |
| 01:44 | 50.093 | +0.093 |
| 01:45 | 50.063 | +0.063 |
| 01:46 | 50.093 | +0.093 |
| 01:47 | 50.094 | +0.094 |
| 01:47 | 50.103 | +0.103 |
What this means
Every generator on the network spins in step with every other, and that shared rhythm is the system frequency. When demand exceeds generation the machines are dragged fractionally slower and the frequency falls; when there is surplus generation it rises. It is the most direct measure of whether the grid is in balance.
Great Britain runs at 50 Hz. Staying within ±0.2 Hz is routine second-to-second variation as demand shifts. The statutory limit is ±0.5 Hz, and reaching it is rare - it usually means a large generator or interconnector has tripped unexpectedly.
Temperature is shown alongside because it is the single biggest driver of electricity demand. A day well below the seasonal norm means more heating, and the demand curve follows.
Updated at 01:48. This page keeps itself current.