Wind Lulls in 2020 and its relevance to FES 2020
8 January 2021
On 15 October, The Guardian carried the following headline “National Grid warns of short supply of electricity over next few days - System operating at reduced capacity due to low wind speeds and unplanned power plant outages.
The article, by Jillian Ambrose, quoted the National Grid as warning that Britain’s electricity will be in short supply over the next few days after a string of unplanned power plant outages and unusually low wind speeds this week.
The article continued, “Unusually low wind output coinciding with a number of generator outages means the cushion of spare capacity we operate the system with has been reduced,” the company told its Twitter followers.
However, “unusually low wind speeds” are not unusual, in fact they are frequent. The following table shows the extent of these wind lulls during 2020.
Here a wind lull is taken as when wind is supplying less than 5% of demand.
Incidence of wind lulls in 2020
| Month | Total Hours <5% | No. of Lulls | No. of Lulls >5 hours | No. of Lulls >10 hours | Maximum Lull (hours) |
| January | 32.5 | 5 | 3 | 1 | 12.5 |
| February | 12 | 1 | 1 | 1 | 12 |
| March | 39 | 5 | 3 | 1 | 21 |
| April | 70 | 6 | 5 | 4 | 22 |
| May | 124 | 12 | 7 | 4 | 32.5 |
| June | 137.5 | 5 | 3 | 3 | 88.5 |
| July | 58.5 | 8 | 4 | 3 | 20 |
| August | 78 | 13 | 5 | 2 | 21.5 |
| September | 62.5 | 9 | 5 | 3 | 21 |
| October | 36.5 | 8 | 3 | 2 | 13.5 |
| November | 81 | 9 | 3 | 2 | 45.5 |
| December | 48.5 | 4 | 3 | 2 | 25.5 |
| TOTAL | 780 | 85 | 45 | 28 | |
Although demand was significantly reduced during lockdown and reduced commercial activity, there were wind lulls of almost a day or more in almost every month, with June showing one very extended lull of over 3½ days.
In fact, Great Britain experienced "wind lulls" for almost 10% of 2020, and during that time wind came nowhere near being able to supply enough electricity, particularly at peak times.
The National Grid’s Future Energy Scenarios (FES) published in 2020 proposes massive increases in operational wind capacity (over six times current capacity in one scenario) through to 2050 with concurrent reductions in gas (to zero in one scenario) and nuclear.
Assuming weather patterns are similar in future years, wind lulls will not significantly decrease as the capacity of operational wind turbines is increased.
It is hard to see what GB would have done in 2020 without gas and nuclear, and to contemplate what will happen if the scenarios in FES are adopted as no planned storage capacity could cope with such long periods without any significant generation from wind, even when the planned increase in interconnector capacity is taken into account.