However, without granular data, it was impossible to say what caused the short-term spike in the 15 minutes starting at 00:00 CET on Wednesday, said EnAppSys analyst Jean-Paul Harreman.
“On paper, you can switch from 1 GW import to 1 GW export from 23:59.59 to 00:00.00, but in the physical world there are assets behind this shift,” he said.
The surge was linked to flows at the German-Dutch border, likely because clashing expectations and interconnector flows left both markets short of power, prompting a rush for balancing power, Harreman said.
“It was definitely a shift in imbalance,” said Amani Joas, managing director of CF Flex Power.
Harreman noted that both countries used up all their automatic frequency restoration reserve capacity, but did not tap manual frequency restoration reserves, indicating they had seen that the surge had reached its limit.
Another possibility was a rapid market correction after the discovery of a possible forecasting error, he said.
German TSO Tennet said it did not have an explanation for the spike at the time, but a spokesman added that such a mismatch was “not a unique situation”.
Harreman said there was another spike around 13:00 on Wednesday, to EUR 8,836.72, but that this was clearly linked to a brief outage at Uniper’s Datteln 4 power plant, which took 1,052 MW off the market for about two hours.
A Uniper spokeswoman said today the outage was due to a “technical fault” that was quickly rectified.