German Power Grids Brace for Thursday’s Solar Eclipse

June 7, 2021 Updated: June 7, 2021

FRANKFURT—Electrical transmission networks in Germany are preparing for a solar eclipse this week that could trigger a sudden fall of around 1 gigawatt in solar power output, grid firm Amprion said on Monday.

The event will take place between 09:20 GMT and 11:40 GMT on Thursday in northern Europe, an Amprion background paper said.

Although it is expected to have a more modest impact than 2015’s solar eclipse across Europe—which reduced output by 15 GW in a country that can need up to 80 GW of power on winter days—Germany’s four high-voltage grid operators, or TSOs, must keep the grids in balance because large amounts of power cannot be stored.

“The network frequency has to be stable and swings in production must be balanced,” said an Amprion spokeswoman.

The TSOs can draw on alternative energy sources such as coal, gas, nuclear, and hydroelectric energy. One GW is equivalent to the installed capacity of a nuclear power station.

They have also tendered for 500 megawatts of balancing capacity, through which they can boost power supply within five minutes, and a further 500 MW allowing them to reduce input and quickly smooth variations in supply.

The TSOs, which also include TransnetBW and TenneT, will issue an analysis on Wednesday of the likely grid situation on June 10, Amprion said.

Germany can in theory reap 40 GW of solar power but output depends on sunshine intensity and cloud cover.

Northern German skies could be 20 percent covered by the eclipse, while in southern Germany, the rate will likely be 2.5 percent.

Eastern German TSO 50Hertz said that Berlin could see 13 percent coverage with lower rates in the states of Saxony and Thuringia.

By Vera Eckert