-
Yesterday the GB power market came within 580 MW of demand control or a blackout on what was the tightest day since 2011 or before@neso_energy issued its first Electricity Market Notice of the winter and third (quickly cancelled) Capacity Market Notice. Although the EMN was eventually cancelled, forecasting errors meant the out-turn spare margin was just 580 MW!
This is much lower than the single largest infeed loss which is supposed to be protected. Even a relatively modest generating unit tripping at the peak would have triggered a shortfall and potential blackout.
Certainly at that point NESO would have to look at demand control to avoid a country-wide blackout. From NESO’s official pronouncements you’d never guess how close things got but the data are all there on BMRS. Oh, and it cost over £21 million to balance the system – almost 10x the usual daily cost. BM prices maxed out at £5,500 /MWh and cashout prices were £2,900 /MWh at times.
This blows the Winter Outlook out of the water – peak demand was much higher and the spare margin and interconnector availability were both lower than forecast. In fact, if Viking had not return its offline bipole early (700 MW) it would not have been possible to meet demand.