National Grid Electricity System Operator (ESO) publishes outlook for this winter


  • National Grid ESO forecasts that sufficient capacity is available for winter 2021/22 to ensure safe and secure electricity system operation.
  • The forecast Loss of Load Expectation (LOLE) is 0.3 hours – well within the reliability standard of three hours.
  • The de-rated margin is forecast at 3.9GW (6.6%)

In its annual Winter Outlook, ESO forecasts that sufficient capacity is available for winter 2021/22 and that the forecast shows that margins will be well within the reliability standard. The de-rated margin is higher than in 2015/16 and 2016/17 at 3.9 GW.

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Fintan Slye, Executive Directive of ESO, said:

The Winter Outlook confirms that we expect to have sufficient capacity and the tools needed to meet demand this winter. Margins are well within the reliability standard and therefore we are confident that there will be enough capacity available to keep Britain’s lights on.

The forecast in Winter Outlook updates the early view of winter margins the ESO provided in July 2021 and takes into account recent developments.

Like last winter ESO may issue Electricity Margin Notices (EMNs). EMNs are a routine tool ESO uses to signal to the market that it would like more generation to come onto the system to further increase the cushion of spare capacity. ESO anticipates issuing a number of EMNs broadly similar to last year.

The ESO will continue to update its analysis based on the latest information and will issue revisions to the analysis should anything significant change.

Read more about Winter Outlook