In depth Analysis of Uk's current Energy situation15 Oct 2021 17:45
* Structural vulnerabilities in the power market makes security of supply less assured*
National Grid ESO’s Winter Outlook sees a capacity margin of 3.9 GW, or 6.6%, lower than the 4.3 GW or 7.3% it anticipated in it’s early outlook published in July with a loss of load probability of 0.3 hours, up from 0.1 hours in the early outlook. The reasons for the deterioration are changes to the generation mix with slightly lower gas-fired generation and the IFA outage which has removed 1 GW of interconnector capacity since the early outlook.
Unfortunately National Grid ESO has left its nuclear forecasts unchanged, which it explained in the early outlook was based on average availability over the past 3 years. This may be optimistic: as these assets age their reliability is rapidly declining. Right now, EDF has two reactors on planned maintenance, and five on un-planned outages, with seven reactors operating at normal full load. The winter outlook assumes a de-rated capacity of 5.4 GW for nuclear this winter (versus base case installed capacity of 7.1 GW, with a 75% de-rating factor). The reactors currently on un-planned outages have a combined capacity of 3.4 GW representing 2.6 GW of de-rated capacity or two thirds of the capacity margin.
https://watt-logic.com/2021/10/15/security-of-supply-3/