Wind Lulls in 2024
The Electricity System Operator for Great Britain (ESO) publishes its Future Energy Scenarios (FES) every year. The latest, FES 2024, show a significant increase in installed wind turbine capacity connected to the National Grid. In their Holistic Transition scenario onshore wind increases by 16% from 8.0GW in 2023 to 9.3GW in 2024. For offshore wind the increase is 26%, from 14.0GW to 17.7GW. FES2024 acknowledges a problem it calls “Dunkelflaute”. This is to a when there is little or no wind – a wind lull.
The table below shows the periods when wind contributed less than 10% of grid demand in 2024 and confirms that “Dunkelflaute” has a significant effect on the contribution of wind to demand.
| Month | Total Hours <10% | No of Lulls | No of Lulls >5 hours | No of Lulls >10 hours | Maximum Lull (hours) |
| 2024 | | | | | |
| January | 22 | 5 | 2 | 0 | 7 |
| February | 92 | 6 | 5 | 3 | 38 |
| March | 90.5 | 11 | 7 | 2 | 29 |
| April | 57.5 | 4 | 3 | 2 | 23.5 |
| May | 264 | 12 | 8 | 6 | 93 |
| June | 98.5 | 10 | 6 | 4 | 31.5 |
| July | 179.5 | 22 | 11 | 5 | 40 |
| August | 61.5 | 10 | 4 | 2 | 23 |
| September | 97 | 13 | 7 | 3 | 28 |
| October | 67.5 | 8 | 5 | 3 | 30.5 |
| November | 169.5 | 15 | 6 | 4 | 88.5 |
| December | 98.5 | 3 | 2 | 2 | 61.5 |
| TOTAL | 1298 | 119 | 66 | 36 | |
| cf 2023 | 1324.5 | 137 | 82 | 45 | 72 |
The table confirms not only that low wind speeds occur, but that they are frequent and often extended. It also indicates overall that weather patterns have remained the same as the previous year.
It also shows that a significant increase in wind turbine capacity from 2023 to 2024 has had little effect in reducing the number and duration of wind lulls.
Of particular concern is the extended wind lull of 93 hours, almost 4 days, experienced in May. The shortfall was met be gas and interconnectors but by 2050 there will be no gas and how reliant should we be on interconnectors?
FES2024, in “Holistic Transition” not only predicts that wind generation capacity will increase by 4.5x by 2040 but that this will represent over 64% of the generating capacity connected to the National Grid. (There is a significant increase in imports via interconnectors and an increase in storage predicted but these are not generating capacity.)
Obviously a reliance on a strategy where wind represents over 60% of generating capacity is not sound and having recognised that wind lulls exist, the National Grid should revisit their strategy.