Britain just set a curtailment record — and the forecast was never wrong

8 September cost £29.7m to manage — the most expensive day of constraint management on record, in cash and in real terms. It beat the previous record, set four days earlier, by 11%. And 90% of the bill was not what we paid to waste the wind.

If you looked at Elexon's wind generation page on Tuesday, you would have seen what appears to be a spectacular forecasting failure. A day-ahead forecast of roughly 17.0 GW. Metered output of 13.3 GW. A gap of more than 3.7 GW, holding open all day.

It has essentially nothing to do with forecasting.

It was, however, the most expensive day of constraint ma…