Germany’s nuclear power “stress test” suggests limited runtime extension could make sense - media

The grid “stress test“ conducted by Germany's power transmission grid operators suggests that letting two of the remaining three nuclear plants in the country run longer than planned could help maintain supply security over the coming winter, business daily Handelsblatt reports. Citing sources from within the economy and climate ministry (BMWK), which oversaw the stress test, the newspaper says that minister Robert Habeck is likely to decide a runtime extension for the reactors. “There are strong signs that this cannot be avoided,” a ministry official said, according to Handelsblatt. The BMWK did not officially confirm that a runtime extension is being prepared, arguing “there is no final stress test result” yet that would allow any conclusions.

In July, the ministry tasked Germany’s four transmission grid operators to conduct the test that is supposed to assess the effects of a continued operation of the reactors beyond their scheduled decommissioning on 31 December this year, given current developments regarding energy prices, gas supply and power production in Germany and neighbouring countries. A first assessment made earlier this year under different assumptions had found that letting the plants run longer is not advisable -- a finding that was heavily contested by nuclear power advocates.

According to the article, the two plants located in southern Germany -- Neckarwestheim in Baden-Wurttemberg and Isar 2 in Bavaria -- are considered to be supportive in the energy crisis. Of three scenarios calculated for the stress test, two suggested "positive effects" of letting the plants run several months longer. Handelsblatt writes that coal power capacity in the south is insufficient to fully replace nuclear power after December, since gas-fired power plants cannot be used as initially planned due to the gas supply crisis. Moreover, there are not enough power transmission lines that can transfer excess wind energy from northern Germany to the southern states. The test only accounted for a so-called “stretched operation” scenario, whereby reactors keep running with the remaining nuclear fuel rods for several months longer than planned and no new fuel rods are procured. It therefore did not test the grid situation after the heating period ends next year. Several politicians, including finance minister Christian Lindner from the Free Democrats (FDP) and Bavaria’s state premier, Markus Söder, from the conservative Christian Social Union (CSU), had called for extending the runtime for several years.