The UK grid issued a rare warning that power supply will be tight on Tuesday and asked coal plants to stand by as a snowy cold snap strains the system.
The grid’s market shortfall is 700 megawatts below its desired buffer, and it’s ready to call on a further 370 megawatts from its back-up coal units if needed, according to an update from National Grid Plc Tuesday afternoon. The shortfall is easing from when the alert was first issued Monday night, but shows more still needs to be done to keep power supplies stable.
The network operator has asked four out of five contingency coal units to warm up in case they’re needed to boost supplies and will decide whether to ask households to reduce demand on Wednesday.
In what’s likely to be the last cold snap this winter, temperatures in London plunged as much as 5.1C (9.2F) below normal on Tuesday. In addition to the freezing weather, wind generation slumped to provide just 13% of the nation’s power capacity, according to grid data on Bloomberg.
The electricity market notice was triggered by the grid manager’s control room because the shortage can’t be addressed through usual measures like asking power plants to generate more or by cutting consumption. The grid notice goes beyond an automatic warning, which has been triggered several times already this winter, but it doesn’t mean power cuts are imminent.
The UK network has struggled to balance the grid at times this winter when cold weather caused demand to surge and wind generation was low. National Grid is operating the system with a shrinking fleet of conventional generation as old coal and nuclear plants shut down. A contingency reserve of coal units hasn’t been secured for next year and two of the plants are slated to close permanently at the end of this month.
Leaning on Coal
National Grid is leaning on coal to potentially boost supplies. The network operator asked three more coal units to prepare to generate on Tuesday after requesting an Electricite de France SA unit to warm up on Monday.
“We are asking generators to make available any additional generation capacity they may have,” the system operator said in a statement. The notice “does not mean electricity supply is at risk.”
Households under pre-agreed contracts may be asked to cut demand on Wednesday to help balance the grid during peak times, according to a notice on National Grid’s website.
The Met Office has weather warnings for snow in place throughout the UK, including London, through Thursday. Wintry conditions will continue on Friday in northern areas. Some places will have as much as 10 centimeters (3.9 inches) of snow, according to the forecaster.
The next step in the power market would be a High Risk of Demand Control warning or Demand Control Imminent notification. Neither of these have ever been used.
In this situation, local grids might reduce voltage to manage demand, or — in more severe situations — might temporarily disconnect some consumers, according to the grid.