National Grid says that the country has the electricity generating capacity to meet the average maximum need over the course of the UK winter. But this calculation critically depends on the reliability of power stations as well as an accurate assessment of the true generating capacity of each plant. This article looks at National Grid’s assumptions on power station availability over the next months and casts a somewhat surprised eye on its apparent errors, particularly in calculating the likely output from nuclear stations.
These mistakes – if they are mistakes – may not matter. The Grid has introduced new payments for cutting electricity demand, meaning that the spare capacity margin is around 3.4 GW or 6% of maximum expected demand in the average year. However what I believe may be its errors over nuclear power reduce this number by at 50% at the very least. It seems strange that the business at the centre of the electricity industry in this country appears to be substantially over-optimistic in its assessment of power supply. It seems it has ignored evidence published by EdF that its nuclear power stations cannot possibly reach the output that the Grid projects over the winter months. Read the rest of this entry »