Landshut, Germany - December 29, 2019: The Isar 2 nuclear power plant, which according to the German federal government is to be taken off the grid in 2022. The Isar 2 nuclear power plant was connected to the power grid in 1979 and supplies the region of Bavaria and neighboring countries with electricity. The Isar 2 nuclear power plant has an output of 1,485 megawatts. Nuclear power Isar 1 was shut down on March 17, 2011.

How tense the situation on the gas market is can be seen these days from the debate about a form of energy long believed to be dead in Germany. The discussion about nuclear energy, which has been the subject of hard struggle for decades, appears shortly before it is finally used like a genie that doesn’t really want to go back into the bottle.

“Not a single cubic meter of gas should have to be converted into electricity. That’s why it would be right now to extend the operating times of the nuclear power plants beyond the winter,” said Christian Dürr, head of the FDP parliamentary group, on Monday. “Dear green ones, jump over your shadow. No bans on thinking. Do it for Germany,” wrote CDU leader Friedrich Merz in an article for “Bild”. The Greens, on the other hand, speak of a “sham debate”, the traffic light coalition is divided.

But if everything goes according to plan, the last three nuclear power plants will be shut down in less than six months. This was decided in the nuclear phase-out in 2011. The remaining power plants Isar 2, Emsland and Neckarwestheim 2 currently account for around five percent of German electricity production. Their output of 4.3 gigawatts is secured, unlike that of wind turbines and solar systems when the wind isn’t blowing or the sun isn’t shining.

The war in Ukraine and the gas price crisis have been fueling the debate for months and are giving supporters of a lifetime extension enormous momentum. Most recently, even the “economy” Veronika Grimm had spoken out in favor of longer nuclear power plant operating times. Brandenburg’s Prime Minister Dietmar Woidke (SPD) was also open to extending the lifespan of nuclear power plants for a short time, as he said on Thursday. But how realistic is continued operation – and what are the benefits?

In essence, it is currently about a so-called stretching operation beyond December. Because the operators of the nuclear power plants had prepared themselves in the long term for their term to end in December – the fuel was ordered accordingly. In stretch mode, the power plants would no longer run at full power, but energy could continue to be generated from the remaining reactivity of the fuel in the winter months.

“With the stretching operation, it is basically possible to gain another 60 to 90 days – with successively reduced performance,” said Christoph Pistner to the Tagesspiegel Background. Pistner is Head of Nuclear Technology and Plant Safety at the Öko-Institut in Freiburg. For him, “the stretching operation is no more unsafe than regular operation”. It is also a common practice when handling fuel rods.

Horst-Michael Prasser, Professor Emeritus for Nuclear Energy Systems at ETH Zurich since 2021, also believes stretching is possible. This is a “long-tested and practiced possibility to generate additional energy for up to twelve weeks without additional nuclear fuel”. Normally, the costs even drop slightly when running stretching operations, Prasser said. However, this is only an option for a lifetime extension if the operator concerned has not already planned in this way up to the date of the nuclear phase-out.

But what effects does this have on gas consumption? “The benefit is very limited,” Pistner said. Gas consumption in Germany consists primarily of heat generation in private households or industrial applications. In the field of electricity generation itself, many gas-fired power plants also supplied heat, in addition to electricity, which could not be provided by nuclear power plants. “The same applies to gas-fired power plants, which are only used to produce electricity: nuclear energy has a completely different load profile. It cannot sensibly replace the function of gas-fired power plants for very short-term power balancing.”

The effort involved is immense: the Atomic Energy Act would have to be changed because the phase-out would be postponed; Security questions would have to be answered; And finally, there are questions of liability in the event of an accident or damage. Most recently, the Energy Brainpool analysis institute calculated that a longer service life for nuclear power plants would only replace one percent of Russian natural gas.

For Pistner, too, it is questionable whether the stretching operation was not already planned in the calculation of the fuel quantity until December. The result would be: A later stretching operation is impossible, unless the output of the nuclear power plants is already reduced in the summer.

At least for Isar 2, however, there is a report from TÜV Süd, which states that operation beyond December is still possible. For observers, there is actually a lot to be said for the fact that the stretching operation is already planned for the months up to December in the remaining power plants. It is simply more economical to fully utilize the energy of the fuel elements. In addition, the so-called residual electricity quantities from Isar 2, i.e. the quantity of electricity that is still assigned to the power plant according to the Atomic Energy Act and can be consumed, were larger than in the other reactors.

As early as March, the environment and economics ministries made it clear in a joint test report that there was nothing to be gained by stretching the pile. The fuel elements are largely used up. By reducing the output in the summer of 2022, operations can be continued for up to 80 days. “Overall, no more electricity would be produced between now and the end of March 2023,” it said. “Procurement, production and nuclear approval for the production of new fuel elements for a functional reactor core usually takes 18 to 24 months.”

Prasser, on the other hand, has no technical concerns about letting the systems run longer. “The remaining nuclear power plants could run safely for 60 years or much longer without any problems if supply chains for maintenance and the preservation of competence in the field of nuclear technology are secured,” said Prasser. The only hard criterion for decommissioning is the neutron embrittlement of the reactor vessel. According to Prasser, it is a “good interim solution” for the introduction of even better reactors. “It’s just a political acceptance issue.”

For those who are thinking about this longer use of the nuclear power plants over several years, the Federal Office for the Safety of Nuclear Waste Management (Base) lists numerous reasons that speak against their operation. In terms of safety, this means, for example, that “high-risk systems would be operated longer for which the mandatory safety checks with a view to the impending shutdown have not taken place since 2009”. On request, it also says: “The uranium of the fuel rods also comes largely from Russia, and any stretching operation with the fuel rods still in use for a few weeks would not make any significant contribution in terms of energy technology.”

Pistner is skeptical about the benefits of continuing to operate the power plants for years to come. There are not only the fuel elements, which have to be ordered at least twelve months in advance. The planning for highly qualified staff would have to be adjusted at very short notice. There are also questions about their safety: “It is necessary to completely check the safety of the systems again,” says Pistner. The last periodic safety check was due in 2019, only because of the nuclear phase-out it was waived. A test takes years. “The effort would be enormous,” Pistner said.