London — UK electricity demand fell to 15.347 GW early Sunday morning, 12.3% below last year's minimum demand and close to a record low, initial out-turn figures from National Grid showed Monday.
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While extremely low, Sunday morning demand did not sink to the 14.4 GW forecast made by the system operator May 7, when it announced it had contracted EDF Energy to reduce generation at its Sizewell B nuclear plant in Suffolk for several weeks.
"No emergency instructions were issued, but we are checking to see if this was a record low for demand. It was very similar to that of the bank holiday Easter weekend," a National Grid spokesman said.
The Optional Downward Flexibility Management product was used, the spokesman said.
This is a new voluntary service for small-scale renewable generators to receive payments from the system operator if it asks them to turn down or turn off their generation.
"Demand was not as low as forecast, this was possibly because the pick-up in wind generation was slightly later than predicted," he said.
Sunday's demand low was almost exactly in line with National Grid's "high impact" coronavirus scenario, set out in its April 14, Summer 2020 Outlook. This foresaw minimum demand of 15.3 GW and minimum generation of 34.9 GW available.
To handle this disparity, National Grid said it could request pumped storage units to increase demand by moving water back to top lakes, curtail flexible wind farm output at a national level via the Balancing Mechanism or via direct trade, trade to reduce the level of interconnector imports, and issue local or national Negative Reserve Active Power Margin (NRAPM) notices, allowing the system operator to request additional plant flexibility.
On May 1, regulator Ofgem approved an emergency grid code amendment allowing National Grid to disconnect small generators as a last-resort action to preserve system security.
Applying for the modification April 30, National Grid said it was needed due to "the unprecedented societal changes brought about by the COVID-19 pandemic which has led to demands out-turning up to 20% lower than predicted."
In the event, however, it did not need to call on this emergency power.