Were you surprised that there's a problem when there's a wind lull?

20 October 2020

This news item on 15 October 2020 by Jillian Ambrose in the Guardian reported the National Grid's warnings that electricity would be in short supply over the next few days, due to low wind speeds and a string of unplanned power outages.

The second half of week commencing 12 October 2020 certainly did feature low wind, as you can see from our Recent Performance page.

However, it would be misleading to suggest that this is a rare occurrence, as we have pointed out on numerous occasions. And the bad news is that with the current National Grid plan this is going to happen more and more frequently.

Here are the key factors that are causing this to happen and will cause it to happen more often:

• Great Britain experiences extended wind lulls of varying duration, and these are intermittent and largely unpredictable.
• Reductions in fossil fuel sources - notably gas (to zero in one scenario) and including the total removal of coal (which is still used to deal with intermittency in GB) and reductions in nuclear capacity mean that we have limited controllable sources to use to compensate for the intermittency of wind.
• The dependence on wind will increase - by up to about 6 times - and so the deficit between supply and demand that we currently cover primarily using fossil fuels will be even greater.

Unfortunately the National Grid's approach to modelling does not seem to include the use of actual experienced wind and light patterns (e.g. what happened in 2019?). If it did, they would see that the projected changes to supply and demand do not facilitate the level of supply resilience that is their target. Modelling years from now to 2050 based on actual recent years would show that there will be more and more years where supply cannot meet demand for long periods of time.

Two of the key sources that the future plans rely on to compensate for intermittency are interconnectors and storage. However, the planned approach with both of those will not solve the problem:

• Although the forecast volume of imported power available via interconnectors could help in some situations, the plan is generally for GB to export more power than it imports. When we need that power will we always be able to get it? Will we be required to export power when we don't have enough for ourselves? Given the "equal" nature of the agreements with our interconnector partners, the answers to those questions will not always be in GB's favour. There will also be occasions when even the full amount of interconnector import power available to us would not be enough.
• The quantities of storage that are planned will be totally inadequate to deal with the extended wind lulls that will occur. Current projected storage volumes might cover a few hours of low wind, but not days.

With the current approach and plans, expect the National Grid to be issuing such warnings - and being forced to impose power cuts - on an increasingly regular basis over the coming years.