Last Saturday, power generation in Germany went on a roller coaster once again.
As usual on sunny days in August, solar systems feed strongly into the grid during the day.
But towards the evening the picture changed, and suddenly: While the photovoltaics still supplied more than 30,000 megawatt hours from 1 p.m. to 2 p.m., and thus more than any other energy source, between 7 p.m. and 8 p.m. the feed-in shrank to less than 3,000 megawatt hours.
Niklas Záboji
Editor in business.
Follow I follow
This was not without consequences for the power grid: Because demand remained practically unchanged at around 50,000 megawatt hours into the evening, reserves such as pumped storage had to be activated. Lignite power plants were running at full speed, and more electricity was being imported. But none of that was enough. From 7.49 p.m. the network operators therefore pulled out more stops and took four industrial plants off the network, including the Trimet aluminum smelter in Essen, with the “loads that can be switched off immediately” (SOL).
Eleven minutes later, bulk consumers continued to be dropped across Germany. Now, at the behest of the network operators, several of the “quickly disconnectable loads” (SNL) have also been disconnected from the power supply in order to balance generation and demand.
They have a lead time of a few minutes, while the SOL go offline within 350 milliseconds.
The drops lasted until 9 p.m.
Then calm returned.
The industrial companies affected were regularly compensated - they can apply to be ready to shed loads, the costs are allocated to the electricity price - and were able to resume production.
"Can't see any increase"
All other consumers in the country should not have noticed anything of the interference. This is one of the reasons why the network operators are decidedly relaxed in the aftermath. “On Saturday, the interruptible loads were used due to a high need for regulation”, says a spokeswoman for Amprion of the FAZ. The use was “according to the concept as part of the system management toolbox”, and from the point of view of the network operator there was “no anomaly”.
Amprion also rejects concerns that the bottlenecks will increase due to the expansion of wind and sun. "The forecasts for the electricity market are essentially weather-dependent," says the spokeswoman, "we cannot determine any increase in the deviations here." Artificial intelligence is also used, which makes the weather forecasts more and more reliable. “The loads that can be switched off have been used less and less in recent years. The average retrieval probability for interruptible loads in 2020 was 0.02 percent, ”said Amprion.
Business representatives emphasize that it has to stay that way. "Security of supply is a valuable asset for Germany as an industrial location," says Alexander Kronimus from the Association of the Chemical Industry. "Even brief interruptions in supply can lead to major economic damage in industry."
The Federal Glass Industry Association is even clearer and warns of damage in the six-digit range. "The issue of power grid stability is right at the top of the agenda in the glass industry, as the glass melting process is characterized by a high degree of continuity," says a spokeswoman. Glass tanks are in operation 24 hours a day, 365 days a year, and the melting process reacts very sensitively to fluctuations in the stability of the power grid. Even short interruptions or fluctuations could therefore lead to hours of production downtime and have a negative effect on the electronic components on the glass tubs.