UK Gas Plants Enjoy January Boom

UK combined-cycle gas turbines (CCGT) did very well out of the mid-January cold spell, where wind turbines were almost still, according to analysis by Cornwall Insight published February 9. Day-ahead prices reached £1,000 ($1,380)/MWh or higher on seven separate occasions including four consecutive days between 11 and 14 January, while imbalance prices reached a record high of £4,000/MWh, it said.

During this time, the vast majority of offer volumes on the balancing mechanism (BM) came from older CCGT plant, with additional generation from open-cycle gas turbines and pumped storage. Water is pumped uphill to fill a reservoir at night when power is cheap, and released to drive turbines during peak hours.

Across the seven settlement periods where the single imbalance price exceeded £1,000.0/MWh, accepted offer volumes from CCGT plant totalled 3.96 GWh, accounting for 93.5% of all accepted offer volumes.

Cornwall said: "These price spikes were a result of tight supply margins from a combination of low wind output, with outages at CCGT, nuclear plant and interconnectors. In addition, cold weather led to demand exceeding National Grid Electricity System Operator's (ESO) Winter Outlook forecast levels. This led to the ESO issuing Electricity Margin Notices (EMNs) for the evenings of 6, 8 and 13 January.

"These price spikes serve as a reminder of the volatility of system conditions and wholesale markets. There is the potential for such fluctuations in power prices to become more frequent in the near-future as older dispatchable generation assets retire and the share of weather-dependent renewable generation increases, whilst the flexibility and response markets – which will help to smooth out any issues – continue to develop in terms of scale and sophistication," it said.

For more analysis of the role of CCGTs in the UK power mix, please see a late January NGW Magazine feature here.