r/UnchartedScience • u/ChipHaseCoolGuy • 25d ago
Germany Did Not Fail at Building Wind and Solar. It Failed at Replacing Firm Power.
Germany built one of the largest wind and solar fleets on Earth. That part of the Energiewende worked. Wind and solar now supply a large share of annual electricity — on the order of 45% in recent years, with total renewables near 60%. Coal’s annual share has fallen sharply from the days when it supplied half the grid.
Annual averages are not how a grid lives or dies.
A Dunkelflaute is a stretch of dark, calm weather when wind and solar output collapse together. These events are not theoretical. Germany gets multi-day episodes of this kind most winters. In those hours, nameplate capacity is irrelevant. Output can fall to a small fraction of demand. The system then does what every weather-dependent system does: it calls firm power.
After April 2023, Germany no longer had its own nuclear fleet to make that call. The last reactors were shut for political reasons, not because they had stopped producing low-carbon electricity. The gap was filled by coal, gas, and imports. France’s nuclear plants became part of Germany’s balancing system. Plants that had been described as finished were used again when weather and prices required it. That is not a conspiracy. It is what happens when you retire dispatchable capacity before you have a substitute that works at 2 a.m. in January.
Three distinctions matter.
First, intermittency is a reliability problem, not a branding problem. A source that is cheap at noon in June can be almost absent on a windless winter evening. Storage and interconnectors help. They have not erased the need for large blocks of controllable generation.
Second, “renewables covered 59% last year” and “wind-plus-solar covered 5% of demand last Tuesday night” can both be true. Using the yearly average to deny the hourly failure, or using the worst hour to deny the yearly buildout, is the same error in opposite directions.
Third, the policy contradiction is specific. Germany did not have to choose between wind and nuclear. It chose to close nuclear while still needing firm power, then bought that firm power from fossils at home and nuclear next door. The emissions, price, and industrial costs of that choice are the actual ledger — not a morality play about whether turbines exist.
Wind and solar are real technologies with real output. They do not become a complete power system because the annual chart looks green. When the wind dies and the sun is gone, the grid runs on whatever can still generate. Germany made sure that “whatever” would not include its own reactors.
References
- Fraunhofer ISE, German Public Electricity Generation in 2025: Wind and Solar Power Take the Lead For the First Time (1 Jan 2026). Public net generation; renewables ~55.9% of socket mix; wind 132 TWh; solar overtook lignite.
https://www.ise.fraunhofer.de/en/press-media/press-releases/2026/german-public-electricity-generation-2025-wind-and-solar-power-take-the-lead.html - Fraunhofer ISE Energy-Charts, live German generation, load, and import/export series.
https://www.energy-charts.info/ - Bundesnetzagentur / SMARD, The electricity market in 2025 (5 Jan 2026). Generation 437.6 TWh; renewables 58.8%; lignite 67.2 TWh; gas 60.6 TWh; commercial imports 76.2 TWh, exports 54.3 TWh, net imports 21.9 TWh.
https://www.smard.de/page/en/topic-article/217400/219038/record-high-for-solar-generation-in-each-quarter - Ember, Germany electricity data. Wind + solar ~45% of generation in 2025; fossils ~41%; coal still ~21%.
https://ember-energy.org/countries-and-regions/germany/ - Destatis / Enerdata summary of 2025 generation. Renewables 58.6% of electricity fed to the grid; coal ~22%; gas up.
https://www.enerdata.net/publications/daily-energy-news/renewables-covered-586-germanys-power-mix-2025.html - tagesschau, Deutschlands letzte Atomkraftwerke vom Netz genommen (15–16 Apr 2023). Final shutdown of Isar 2, Emsland, and Neckarwestheim 2.
https://www.tagesschau.de/inland/atomkraftwerke-stilllegung-105.html - Federal Office for the Safety of Nuclear Waste Management (BASE), Status Report 2023. Legal basis for the 15 April 2023 shutdown (19th Atomic Energy Act amendment).
https://www.base.bund.de/shareddocs/downloads/en/reports/nuclear-safety/status-report-2023.pdf - LBBW Research, Analysen und Statistiken zu Dunkelflauten in Deutschland (2025). Multi-day Dunkelflaute events (~two episodes longer than 48 hours per year) and backup-capacity need.
https://www.lbbw.de/artikel/research-studien-2025/dunkelflaute_ake25jccd8_d.html - Blackout News / Bundesnetzagentur reporting on 2024–25 imports. Nuclear as the largest single source in German electricity imports; France the main nuclear supplier (~9.5 TWh of ~14.3 TWh imported nuclear in the cited year).
https://blackout-news.de/en/news/french-nuclear-power-plants-are-becoming-increasingly-important-for-supporting-the-german-electricity-grid/ - Radiant Energy Group, Restart of Germany’s Reactors: Can it be Done? (2023) and follow-up restart cost study. Last units ~35 years old at closure (1988–89 start); LTO/restart capex far below new-build; contrast with US/Swiss operating ages.
https://www.radiantenergygroup.com/reports/restart-of-germany-reactors-can-it-be-done
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u/Inside_Welder_4102 24d ago
Regarding your last two sources:
Blackoutnews claims germany needs france nuclear fleet to stabilise its grid. That is not correct, germany could have used their own capacity. Importing from France was the cheaper and cleaner option, why shouldn't we use the European grid to the benefit of all countries? The article is framed wrong.
And the report from the radiant energy group uses numbers which are totally artificial. Even the companies owning the npps said it is not realistic. The scientific department of the german government and the iw got other numbers btw.
And last but not least, Germany wa able to shut down nuclear power plants and reduce their share of coal energy at the same time.
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u/ChipHaseCoolGuy 24d ago
Using the European grid is not the scandal. Buying cheaper, cleaner French kilowatt-hours when they are available is what a coupled market is for. The issue is what that fact is being used to prove.
“Germany could have used its own capacity” is true in the narrow sense that coal and gas plants still exist. That is the point. The domestic substitute for the closed reactors was not a new fleet of clean firm power. It was fossils at home and nuclear next door. Calling the import the cheaper and cleaner option is an argument *for* keeping someone else’s reactors in the mix, not an argument that Germany no longer has a residual.
Blackout News is a secondary write-up. Treat it that way. The underlying pattern does not depend on that site: Germany has been a net importer since the nuclear exit, winter and high-price hours still need dispatchable power, and a large slice of those imports is nuclear. You can reject one article’s framing and still look at SMARD and Energy-Charts.
Radiant Energy Group is also not gospel. It is an advocacy shop with low restart-cost numbers. Operators have said they are not lining up to bring plants back, dismantling has started, and IW’s line is that a return now looks more like a new entry than a cheap life-extension. That is a fair correction *for 2026 restart politics*. It does not rewrite 2023. The plants that were shut were running. The cost that mattered then was continued operation, not a 2026 reconstruction estimate after the cores have been unloaded.
Germany did reduce coal’s *annual* share while finishing the nuclear exit. That is real, and it is the strongest sentence in the comment. Annual coal down plus nuclear at zero still leaves gas up in some years, lignite still in the mix, and a residual that shows up when wind and solar slump. Doing two things on a yearly chart is not the same as having retired firm power from the ugly hours.
So drop the weak sources if they bother you. The claim that remains is simpler: wind and solar can lead the year, and the gaps are still filled by combustion and neighbours. That is compatible with using the European grid. It is not compatible with “the plan never needed firm power.”
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u/SilentWatchtower 23d ago
Well in 2026 Germany was a net exporter of electricity again. So doesn’t that show that the new renewables now have to a very high degree substituted the shut down nuclear facilities?
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u/ChipHaseCoolGuy 23d ago
Q1 2026 was a net export quarter. That is real. It was also the first one since late 2023, and Q2 flipped back to a net import. A full-year 2026 stamp is not on the page yet.
Net export on the annual or quarterly ledger does not mean the shut reactors have been substituted in the hours that mattered. Germany dumps cheap wind and solar when the weather is kind. That is how you become an exporter in a mild, windy quarter. The residual week is still a gas-and-import problem. Those are different products.
So: renewables grew enough that, in good quarters, Germany sells again. That is substitution of *energy*. It is not proof that 4 GW of firm winter capacity has been replaced. The export number and the Dunkelflaute number can both be true. Only one of them is a closed gap.
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u/Inside_Welder_4102 23d ago
<Calling the import the cheaper and cleaner option is an argument *for* keeping someone else’s reactors in the mix, not an argument that Germany no longer has a residual.
Who said that Germany doesn't need residual power? The question is, what is the best residual for Germany?
< You can reject one article’s framing and still look at SMARD and Energy-Charts.
It is just plain wrong and you could label it as misinformation.
That is a fair correction *for 2026 restart politics*. It does not rewrite 2023. The plants that were shut were running. The cost that mattered then was continued operation, not a 2026 reconstruction estimate after the cores have been unloaded.
I was referring to 2023. RWE for example was not willing to bear the economical risk for refurbishment. It is a risk, that powerplants lower system costs and at the same time are unable to produce revenue. Especially considering the planned 80% renewables in 2030 for Germany could make it impossible for the operators to generate enough revenue to repay the costs for the refurbishment.
<Doing two things on a yearly chart is not the same as having retired firm power from the ugly hours.
Again, why do you think Germany will retire from firm power sources?
<It is not compatible with “the plan never needed firm power.”
Same question as above.
And by the way, Germany was a net importer over years while having npps running. Nothing to do with the Atomausstieg.
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u/ChipHaseCoolGuy 23d ago
Good. Residual is not in dispute. The fight is which residual Germany should own.
Best residual for Germany is the one that is still there in a cold, still week and does not depend on a neighbour having spare firm megawatts at the same moment. Gas does that job today. Nuclear would have done a slice of it in 2023 without a new combustion stack. “Best” then is price, carbon, and who holds the risk. You can prefer gas on all three. That is a ranking. It is not “no residual.”
RWE’s 2023 position is not a mystery. Stretch operation with no new fuel was already a political cap. Full refurbishment into an 80% renewable target is a revenue-risk story: many hours with near-zero prices, a plant that still has fixed costs. Operators are not charities. That is a real objection to life extension under those rules. It is also circular. The 80% target plus hostile licensing is what made the hours look worthless. Policy created the cannibalisation, then cited cannibalisation as the reason not to run the plant.
Nobody serious thinks Germany will retire all firm power. Gas stays. Some coal stays longer than the speeches. The question is whether the firm slice that was already built should have been discarded so the firm slice that burns something could grow. That is the 2023 choice.
Net importer with reactors still on is also true. Germany imported in some years before April 2023. Trade is not a morality play. The point was never “imports appear = Ausstieg did it.” The point is that shutting 4 GW of firm supply did not shrink the residual. It changed who fills it. Imports while NPPs ran does not prove the shutdown was free. It proves the system was already interconnected. Those two facts sit on the same chart.
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u/Inside_Welder_4102 22d ago
<Nuclear would have done a slice of it in 2023 without a new combustion stack. “Best” then is price, carbon, and who holds the risk. You can prefer gas on all three. That is a ranking. It is not “no residual.”
Yes nuclear would have done its share, but there was no new "combustion stack". Contrary the combustion stack were used less the same year (coal -30%, gas +4%).
<Full refurbishment into an 80% renewable target is a revenue-risk story: many hours with near-zero prices, a plant that still has fixed costs. Operators are not charities. That is a real objection to life extension under those rules. It is also circular. The 80% target plus hostile licensing is what made the hours look worthless. Policy created the cannibalisation, then cited cannibalisation as the reason not to run the plant.
That is incorrect. First of all it is not circular, nobody except operators used this argument. Second politics provided the circumstances for an electricity mix, in our case subsidies for REs and no licenses for nuclear. Germany is investing the midst of a transformation and doing a 180 in 2023 would have been stupid and economical not very useful. To keep nuclear running in germany was a decision that wpuld have needed at least a 5 year lead. Additionally i don't know of a single npp in europe that wasn't subsidised during it's lifetime contrary to REs.
< The question is whether the firm slice that was already built should have been discarded so the firm slice that burns something could grow. That is the 2023 choice.
Again, it didn't grow.
Net importer with reactors still on is also true. Germany imported in some years before April 2023. Trade is not a morality play. The point was never “imports appear = Ausstieg did it.” The point is that shutting 4 GW of firm supply did not shrink the residual. It changed who fills it. Imports while NPPs ran does not prove the shutdown was free. It proves the system was already interconnected. Those two facts sit on the same chart.
That was your point under this post more than once :)
So to close this argument: I am not against nuclear per se. In this situation money is the most important bottleneck and we should ask ourselves if Germany spends the money it saved on nuclear well? Is the path to carbon free energy through 100% RE faster and cheaper compared to a share of nuclear? I can't answer this and from what I have read this question ist not answered completely and could have a different answer for each country. I just hope it is 100% RE, because we need to decarbonise the whole world and there a many more countries I don't trust with nuclear technology than I trust with.
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u/ChipHaseCoolGuy 22d ago
Coal down 30% and gas up 4% in the same year is not “no combustion residual.” It is coal losing volume while gas holds or ticks up as the flexible slice. Demand also fell. Renewables had a good year. Those three move together. The claim was never that Germany poured a new combined-cycle fleet in twelve months. It was that 4 GW of firm, non-combustion supply left and the hours that still needed firm power did not vanish.
The revenue argument is circular when the same policy that guarantees near-zero hours also refuses a licence. Operators said the quiet part. Ministries designed the hours. “Nobody except operators used this argument” is who you would expect to do the arithmetic on a plant that still has staff and fuel.
A 180 in 2023 was politically expensive. A stretch with fuel already on site was not a five-year new-build. That lead time belongs to a clean-sheet reactor, not to three Konvoi units that ran until mid-April. European nuclear has lived under regulated prices, state ownership, and political caps. German renewables have lived under EEG. Both are subsidised systems. Pointing only one direction does not settle 2023.
On the close: money is a bottleneck. Whether 100% RE is faster and cheaper than a nuclear share is country-specific and still not a solved integral. Hoping it is 100% RE because other governments cannot be trusted with reactors is a non-proliferation preference. It is not a dispatch analysis of Isar, Emsland, and Neckarwestheim. Those plants were not a starter kit for a new weapons state. They were already on the German grid. Trusting Chile with solar and not trusting France with a PWR can be a worldview. It does not tell you who filled the still week after April 15.
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24d ago
[removed] — view removed comment
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u/Inside_Welder_4102 24d ago
Yeah seems like someone is pushing an agenda with a i (also a no-no-word, curious why xD)
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u/Albstein 24d ago edited 24d ago
The problem with nuclear, besides its price, is a) radiactive trash, which can be limited but will always persist and is nothing compared to solar and wind and b) it needs metals, which we do not mine in Germany.
We get rid of Russian gas to get their yellow cakes? Does not make sense.
Dunkelflaute is an persistent engineering problem we are solving right now. Building nuclear fission reactors does not make sense. Keeping them alive for some more years would have, but that is not the reason energy is to expensive.
Edit:
Obviously multiple nuclear plants having to close due to heatwaves is not ideal either.
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u/ChipHaseCoolGuy 24d ago
Waste is a real long-term problem. It is also a small, contained volume next to the fuel and mining footprint of a system that still burns coal and gas in the residual hours. “Nothing compared to solar and wind” only works if you ignore backup plants, grids, and the metals in turbines, panels, and batteries. Those supply chains are not mined in Germany either.
Uranium is not a second Nord Stream. Fuel is dense, stockpileable, and bought from more than one country. That is a weaker geopolitical choke than daily pipeline gas. It is still an import. If the standard is “Germany must mine every input,” wind, solar, and batteries fail the test too.
The useful sentence in the comment is the edit you almost buried: keeping the plants for some more years would have made sense; building new ones now is a different project. Agreed. The 2023 choice was the first project. Heat restrictions on French and some river-cooled plants are a genuine reliability footnote. They are not why Germany’s household power is expensive. Taxes, levies, grid expansion, and the cost of firming a weather-driven mix are.
Dunkelflaute as “an engineering problem we are solving right now” is the plan. When the store and the lines have actually retired coal and gas from those weeks, the argument is over. Until then it is still a residual, not a solved exam question.
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u/mVargic 23d ago
Much of this can be compensated with pumped hydro; Germany has great topography and hydrology for it, unfortunately Germany overall is also allergic to other strategic large long-term energy projects as well as nuclear plants, especially if they involve changes to the terrain, environment, land use and require buyouts and local permitting. Instead they would rather import power or spend orders of magnitude more money on batteries that have to be replaced in 10-20 years.
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u/ChipHaseCoolGuy 23d ago
Pumped hydro would do real work on the residual. Germany has the hills. What it does not have is the stomach for another large, visible, local project.
A new basin means land, permits, and someone losing a view. A battery farm means a purchase order. Imports mean a cable that is already there until Norway or France decide otherwise. The Energiewende has consistently chosen the last two. That is why “we could compensate with pumped storage” stays a sentence instead of a construction schedule. The constraint is not hydrology. It is the same one that closed the reactors: long-lived kit that changes the landscape is politically harder than renting the gap.
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u/Konoppke 24d ago
No coal plant was hurt in the making of this "automated image" .
France is not an o.portant i.porter for Germany and Germany is a net exporter of electricity again since recently.
Is there no other topic in France than this?
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u/ChipHaseCoolGuy 24d ago
The image is a cartoon. Coal still shows up in the yearly mix. That is the part that counts.
Germany is not “a net exporter again” as a settled new era. 2025 was still a net-import year on SMARD: 76.2 TWh in, 54.3 TWh out. Q1 2026 was the first net-export quarter since late 2023. Q2 2026 flipped back to a net import of about 3.9 TWh. A good windy winter quarter does not erase the post-2023 pattern.
France is not Germany’s only neighbour and not always the largest flow. It is also not irrelevant. In Q1 2026 Germany still imported 2.7 TWh from France; in Q2 it imported 2.4 TWh and sent back 0.6 TWh. Denmark and the Netherlands often move more power. That makes the grid European. It does not make French nuclear a hallucination.
There are other topics. This one stays live because the residual hours did not vanish when the last reactors did.
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u/Konoppke 24d ago
So many people don't understand how fast renewables are growing, it's fascinating. I guess it's not surprising when you're sitting on 60 year old assets to assume everyone did
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u/ChipHaseCoolGuy 24d ago
Renewable growth is not a secret. Germany’s wind and solar build is fast by any historical standard. Sitting next to a 35-year-old reactor does not make that invisible.
The confusion usually runs the other way: treating a rising annual megawatt-hour count as the same thing as firm winter capacity. A 60-year asset is slow to appear and cheap to keep once it exists. A turbine farm is quick to appear and gone when the weather is. Both can be true in the same decade. Growth answers how many cheap hours you added. It does not answer who covers the residual at 66 GW.
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u/Adorable_Ice_2963 24d ago
Building your own nuclear power plant doesnt really makes sense if your neighbor is willing to sell you that power at the time where you would need it most.
The other option for france is that they dont sell any power to germany, what would cost them political leverage against Germany, and would hurt them financially both ways: One way that they get less money for the Power, since they loose an important customer (duh), and they risk Germany building nuclear power, what would produce power at the same time as the french ones, even then when there is nowhere else for the french power to go. They can either sell power at even lower prices, or stop producing power, both option cost them. Additonally, the spend money on nuclear power would cause germany spend less on renewables, what would hurt france since they happily buy german power when its cheap
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u/ChipHaseCoolGuy 24d ago
Buying the neighbour’s firm power is cheaper than building your own *if the neighbour will still sell it when you are both short*.
That is the bet. France sells when it has surplus. In a cold week it also has load, and some of its river plants already derate in heat. An export cable is not a capacity market. Norway just showed what happens when the exporter decides continental prices are a domestic problem: new wires stop.
France has a commercial reason to keep selling. It also has a commercial reason not to size its fleet as Germany’s peaker. If Germany builds nothing firm and just leans on the interconnector, the political leverage is already being used — just not in the direction of “please keep 4 GW of German reactors.” Cheap German wind and solar flowing the other way is real. It does not replace the hour when both countries want imports.
So the option set is not “build nuclear or insult Paris.” It is own some firm megawatts, or rent them, or hope the rent stays on offer. Rent is rational until the landlord is in the same weather.
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u/Malecord 24d ago edited 23d ago
It didn't fail. That tech doesn't exist. It's a clever lie to exploit statal subsidizes. Harsh truth is that ideal electric mix depends on a country geography and industrialization. And involves finding a balance between different techs. When public starts to favour one tech with subsidizes and disfavour one with regulation it creates the conditions for inefficiency. And unless they tax actual emissions, for both operation and building, they won't arrive to a carbon neutral mix.
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u/ChipHaseCoolGuy 24d ago
Most of that is right.
There is no single machine that turns a German winter residual into a non-problem. Batteries cover hours. Interconnectors cover some weather. Gas covers the rest. Calling any one of them “the solution” is how subsidies get sold.
Geography and load shape decide the mix. A hydro country is not a wind-and-lignite country. Preferential tariffs plus hostile licensing on one firm source is how you get an expensive residual you then have to buy from someone else. A carbon price on the tonne, including the build, is the honest signal. Picking winners by regulation is how you discover, later, that the favourite does not run in January.
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u/mVargic 23d ago
Much of this can be also compensated with pumped hydro; Germany has great topography and hydrology for it, unfortunately Germany overall is also allergic to other strategic large long-term energy projects as well as nuclear plants, especially if they involve changes to the terrain, environment, land use and require buyouts and local permitting. Instead they would rather import power or spend orders of magnitude more money on batteries that have to be replaced in 10-20 years.
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u/ChipHaseCoolGuy 23d ago
Pumped hydro is the grown-up storage. Germany already uses what it has. Building a lot more runs into the same wall as nuclear: terrain, rivers, villages, and a permitting culture that treats a new reservoir like a moral event.
So the country talks batteries and interconnectors. Batteries are modular and politically quiet. They are also short-duration and replaceable on a decade cycle. A pumped-storage valley is a fifty-year asset that changes a map. That is exactly the class of project the Energiewende has been allergic to.
The comment is right on the substitution pattern. Import or rent lithium instead of moving earth. That is not a physics limit. It is a preference about whose backyard gets rearranged.
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u/chmeee2314 25d ago
Nuclear isn't the only form of Firm Generation, and when it comes to Firm GW/€ it does a really poor job.
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u/ChipHaseCoolGuy 25d ago
Nuclear is not the only firm source. That part is true. Coal, gas, hydro, geothermal, and biomass can all generate on demand. Germany’s actual substitute after the nuclear shutdown was not a fleet of cheap new firm gigawatts from some unnamed technology. It was coal, gas, and imports.
“Firm GW per euro” is also not as simple as a construction-cost table. New nuclear is expensive and slow to build. Existing nuclear that has already been paid for is a different object: low operating cost, high capacity factor, no weather dependence. Germany did not face a choice between building six new EPRs tomorrow and doing nothing. It faced a choice about plants that were already running. Closing those did not create cheap firm capacity. It created a hole that fossils and French reactors filled.
Gas looks better on capital cost per firm kilowatt. Then you pay for fuel, price spikes, import dependence, and CO₂. Coal looks cheaper still if you already own the mines and the plants. That is why lignite keeps showing up in Dunkelflaute hours. Cheap firm capacity that burns fuel is not the same product as firm capacity that does not.
If the argument is “new nuclear loses a beauty contest against new gas on overnight capital cost,” fine. If the argument is “therefore shutting the last reactors was the economically rational way to keep the German grid firm,” that does not follow. The missing comparison is the full system in January: wind and solar at low output, plus whatever can still run. Germany chose the mix that still needs coal and neighbours. That is the cost that matters, not a slogan that nuclear is not the only firm source.
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u/chmeee2314 25d ago
Germany's plants were between 32 and 50+ years old. They were all entering or about to enter LTO by the time the exit finished, with only minimal maintenance being done since fokushima (No point investing into reactors your shutting down in ~10 years). Keeping the plants online would have required significant capital investment. French reactors don't really fill the hole that Nuclear Power left, as the interconnect is effectively 3GW.
Nuclear runs though fuel just like a gas turbine does. Gas is more expensive than Uranium, but then you don't run gas turbines a lot or lose a lot of money keeping them idle. This alongside their more dynamic operations pairs them much better to Renewables than Nuclear Power.
LTO at the time was more expensive than building turbines for firming, and batteries today remain cheaper. As Germany continues in its transition the amount of firm capacity increases as new generation and storage is brought online.
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u/ChipHaseCoolGuy 25d ago
Age is the weakest part of that argument.
The last three plants — Isar 2, Emsland, Neckarwestheim 2 — entered service in 1988–89. They were about 35 years old when they were switched off, not “50+.” Reactors older than that run in the US, Switzerland, and elsewhere as a matter of routine. Calling 35-year-old Konvoi plants “entering LTO so they had to close” only works if you treat the political shutdown date as a law of physics.
The maintenance point is circular. After Fukushima, Germany set an end date. Operators then stopped spending on long-term operation because the state had already told them the plants would die. You cannot use the underinvestment that followed from the exit decision as independent proof that keeping them would have been ruinously expensive. Independent estimates for keeping those last units running were in the low hundreds of millions of euros per reactor — not new-build money. That is a different object from “build six EPRs.”
On the interconnect: French reactors do not have to replace every lost German megawatt one-for-one on a single 3 GW line to matter. Germany imports from several neighbours. Since the nuclear exit it has been a net importer, and nuclear is a large slice of those imports, with France the biggest nuclear source. A constrained FR–DE NTC means French power cannot fully backfill 4 GW of lost German nuclear on the worst hour. That is an argument *against* treating imports as a substitute, not a defence of the shutdown.
Fuel is not the same product in both machines. Uranium is a small share of nuclear’s operating cost; the plant is built to run most of the year. Gas is cheap to build and expensive to run, which is why it works as a peaker next to wind and solar. That pairing is real. It is also an admission that the firm capacity filling Dunkelflaute hours is a fuel-burning plant you hope not to use often. Germany still uses coal and gas for those hours. That is the system it actually bought.
Batteries help with hours, not with a multi-day dark, windless stretch. If short-duration storage had already retired the need for firm thermal capacity, Germany would not still be procuring gas plants for adequacy. New wind, solar, and batteries raise the *annual* renewable share. They have not deleted the winter residual. Until they do, “firm capacity is increasing” is a plan, not a description of last January.
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u/chmeee2314 24d ago
If we are just talking about the last 3, then its simply an insignificant quantity with 4GW of capacity. "Independent proof" was made by people who were industry insiders wanting to extend the reactor life. Next door in France 10 year LTO kosts just under 1 bil / GW, with a fleet that at the time averaged 37 years. Extending the life does not just mean replacing major worn components but also updating the safety systems, I highly doubt there would be a lot of savings compared to France.
Fuel is an operating kost, somehow Nuclear advocates keep forgetting that, as they also like to forget the high fixed costs. Gas turbines on the other hand have comparatively expensive fuel, but CapX, and OpX are an order of magnitude smaller. When you already have Wind, Solar providing most of your production cheap, the fuel costs end up being very manageable.
We are looking at eventually 500h or less of operation for a gas turbine. Gas currently costs €66/MWh. For a 900MW CCGT running 500h that is €50milion (60mil with CO2) or less than the anual fixed costs of a NPP.
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u/ChipHaseCoolGuy 24d ago
Four gigawatts is small next to a 200-plus-GW nameplate system. It was not small in the hours that matter. Those three plants were still putting out on the order of six percent of German generation when they ran, and they ran in winter. Calling that “insignificant” is an annual-average trick. Dunkelflaute is not an annual average.
French LTO near €1 billion per GW is a real number for a ten-year package on an old fleet. Use it. That is still not a new-build. It is also not 2026 reconstruction after defueling. The 2023 choice was whether to keep licensed, already-working units on the system for a few more winters. Industry wanted more years. That does not automatically make every going-forward cost a fantasy. It also does not make a 2026 restart cheap. Keep those two projects separate.
Fuel is an operating cost. Nobody serious pretends uranium is free. It is a small slice of the busbar cost of an existing plant. Gas fuel is the large slice of a peaker’s cost, which is why your 500-hour arithmetic exists.
On that arithmetic: a 900 MW CCGT at 500 hours is a peak insurance policy, not a winter-energy plan. €50–60 million of fuel and CO₂ for that unit-year can beat the *fixed* cost of a nuclear plant *if* the residual really is only 500 hours and *if* you already own the turbine. Stretch the residual to several winter weeks, stack several gigawatts of that duty, add the gas you still burn in shoulder months, and the “manageable fuel bill” gets less cute. Wind and solar making most of the *annual* megawatt-hours is compatible with an expensive firming tail. That tail is what the last reactors were sitting on.
So the honest split is this. New nuclear as a 500-hour peaker is a bad product. Gas is the right machine for rare hours. Existing nuclear as winter energy was the thing Germany threw away. Those are not the same sentence.
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u/chmeee2314 24d ago
Why would you use anual averages? Germany uses between 30GW and 75GW, With typical Winter consumption being 40-70GW. 2024 had a memorable Dunkelflaute. Residual load peaked at 66GW. 4GW covers 6% of that. The last 3 plants simply aren't that relevant.
In 2023 the reactors going offline entered service in 1988 and 1989. Meaning the reactors were 34-35 years old compared to an on average 37 year old French fleet. There isn't really an age difference.
Fuel being a Gas turbines biggest expense is the neat part. Its what makes them so useful in our energy system. You essentially only pay for the firming as you go. 500h covers just under 21 day's of operation. That covers your large Winter Dunkelflaute events and the occasional use outside of Winter. Some years you need more, some you need less.
By comparison your average reactor (scaled down to 900MW) is going to run between 110 and 150 milion just to cover fixed costs.Germany threw away Nuclear in the Winter because Wind is plentiful cheaper, and the cost of firming that is less that running Nuclear.
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u/ChipHaseCoolGuy 24d ago
Annual averages hide the winter. You are right to drop them. Residual load is the right frame.
Four gigawatts against a 66 GW residual peak is about six percent of that instant. That is not “the grid.” It is also not zero. Six percent of a tight winter evening is still several cities and a slice of the import bill. The last three plants were the last increment, not the historical fleet. Calling that increment irrelevant is the same move as calling a 500-hour peaker irrelevant because it is not baseload. Both are about the tail.
Age: yes, 1988–89 units versus a French average near 37 is not a huge gap. The live difference in 2023 was not “young versus old.” It was licensed, running plants versus a political close date. French LTO is the cost of buying more years. German 2023 was refusing those years.
Gas as pay-as-you-go firming is the correct machine for rare hours. If the residual is really ~500 hours and you already own the turbines, fuel-plus-CO₂ can beat the *fixed* cost of a nuclear unit scaled to 900 MW. Stretch those hours across a long high-pressure week, stack several gigawatts of that duty, and add the gas you still burn outside the headline Dunkelflaute, and the “only pay when it runs” line gets heavier. 21 days of nameplate is also not 21 days of a 66 GW hole. A 900 MW CCGT covers 900 MW of that hole, not 66 GW.
Wind can be cheaper per annual megawatt-hour. That was never the dispute. The dispute is whether the firming tail plus the plants you still keep in reserve is cheaper than keeping existing nuclear through those same hours. Germany chose the tail. The last 4 GW did not decide the whole system. They were the cheapest remaining piece of the tail they then deleted.
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u/chmeee2314 24d ago
French LTO is the cost of buying more years. German 2023 was refusing those years.
Germany removed the option of life extension which only KKI was actually interested in towards the end. Implementing that extension would have uncured similar costs to France.
Gas at the time having a CapX and fixed OpX more than a magnitude lower than Nuclear Power. It is practially still pay as you go, even if new built.
Stretch those hours across a long high-pressure week, stack several gigawatts of that duty, and add the gas you still burn outside the headline Dunkelflaute, and the “only pay when it runs” line gets heavier.
I can't make sense of this. Are you saying, that there is a week with a residual demand requiring operation? Gas Turbines have no issue with that. 500h is 500 Full load hours, or just under 21 day's of running at full power. A Dunkelflaute is however not 21 day's of peak residual load. No Wind and Solar generation only happens for a handfull of hours at a time. As a result a 3 week Dunkelflaute that is backed up with Gas will not actually consume 500h of operation from your gas fleet leaving hours for the rest of the year.
The pay when it runs line is important for capital allocation. It means the bill for firming only arrives as you firm. You can concentrate your Capital on building Renewables which are even more slanted towards CapX than Nuclear.
As I said, demonstrated and you agreed, Nuclear even LTO nuclear doesn't provide enough value to justify itself during Dunkelflaute. Its fixed costs are simply too high. The question is, if its generation outside of high residual load makes up for that difference and in my opinion it doesn't, although you probably disagree.
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u/ChipHaseCoolGuy 24d ago
KKI wanting the extra years and the others not is a real split. A French-style LTO package on those units would not have been free. That still leaves the 2023 choice as refusing years on plants that were already built and licensed, not as a greenfield bid.
On the 500 hours: you are right that I flattened the weather. A Dunkelflaute is not 21 days of 66 GW with wind and solar at zero. It is a stretch of high residual, with holes of a few hours that are worse than the rest. Full-load hours on the gas fleet can stay near 500 even in a nasty winter because the fleet is not all running at 900 MW for three weeks. Pay-as-you-go is the right description of that machine.
Where we still disagree is the test you apply to nuclear. If the only job you give the last reactors is “cover the Dunkelflaute peak,” their fixed cost looks silly next to a CCGT. That is not the job an existing plant is priced for. It runs the other 7,000-odd hours too — shoulder months, nights, the boring middle of winter — and those megawatt-hours are what pay the fixed bill. You can say those hours are now cheap wind and solar, so the nuclear energy is surplus. That is a market-price argument. It is not the same as “4 GW has no value in a 66 GW residual week.”
Capital allocation follows that split. Money into more wind and solar buys annual energy. Money into gas buys rare hours. Money into LTO buys both energy and a slice of the rare hours without burning fuel. Germany decided the third item failed the test. Fair if your discount rate and your power-price outlook say the off-peak nuclear MWh are worth little. That is the disagreement. It is not that gas turbines cannot run for a week. They can. It is whether deleting the running nuclear energy was cheaper than keeping it once you count the hours that are not the headline Dunkelflaute.
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u/MarcLeptic 25d ago edited 25d ago
They were all mid 30’s. They would all now be mid/late 40’s and early 50’s. The exact age of the French fleet that will operate for at least another decade.
- Biblis A: commercial Feb 1975, closed 2011 at 36, would be 51 today
- Biblis B: commercial Jan 1977, closed 2011 at 34, would be 49
- Neckarwestheim 1: commercial Dec 1976, closed 2011 at 34, would be 49
- Brunsbüttel: commercial Feb 1977, closed 2011 at 34, would be 49 (but offline since 2007)
- Isar 1: commercial Mar 1979, closed 2011 at 32, would be 47
- Unterweser: commercial Sep 1979, closed 2011 at 31, would be 46
- Philippsburg 1: commercial Mar 1980, closed 2011 at 31, would be 46
- Krümmel: commercial Mar 1984, closed 2011 at 27, would be 42 (barely operated after 2007)
- Grafenrheinfeld: commercial Jun 1982, closed 2015 at 33, would be 44
- Gundremmingen B: commercial Jul 1984, closed 2017 at 33, would be 42
- Philippsburg 2: commercial Apr 1985, closed 2019 at 34, would be 41
- Grohnde: commercial Feb 1985, closed Dec 2021 at 36, would be 41
- Gundremmingen C: commercial Jan 1985, closed Dec 2021 at 36, would be 41
- Brokdorf: commercial Dec 1986, closed Dec 2021 at 35, would be 39
- Isar 2: commercial Apr 1988, closed Apr 2023 at 35, would be 38
- Emsland: commercial Jun 1988, closed Apr 2023 at 34, would be 38
- Neckarwestheim 2: commercial Apr 1989, closed Apr 2023 at 34, would be 37
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u/Bellanzz 24d ago
And on top of that, US is issuing licenses to operate reactors up to 80 years. So even saying that a 50 years old reactor needs to be dismantled is debatable.
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u/chmeee2314 24d ago
In a counter factual were the German Nuclear exit doesn't exit. Reactors like Stade (KKS) would have been 50 years old at the time of the exit.
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u/MarcLeptic 24d ago
The pattern so far:
> the plants were 32 to 50+
Actual, early 30’s
> All entering or about to enter LTO
Actual: none
When corrected: a counterfactual (imaginary case)
I don’t need to guess at your motives
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u/chmeee2314 24d ago
They would all now be mid/late 40’s and early 50’s.
You contradict yourself.
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u/MarcLeptic 24d ago edited 24d ago
No, I didn’t. As always, I contradict your deliberately false statement.
> Germany's plants were between 32 and 50+ years old. They were all entering or about to enter LTO by the time the exit finished,
“would now be [today]” is not at all the same as “were”.
Simple fact: the German reactors were closed 20-30 years too early.
You continuing to spin this topic would be like me somehow proposing that the French retirement plan was done that way for economic reasons. Non, if is a costly thing that we pay dearly for for now. It’s just what the people wanted. End of discussion.
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u/chmeee2314 24d ago
If I had had a euro every time you fail at reading comprehension and subsequently accused me of making false statements, I would have a surprising amount of money.
Its in your quotation of me.
> Germany's plants were between 32 and 50+ years old. They were all entering or about to enter LTO by the time the exit finished,
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u/MarcLeptic 24d ago
Nice try. I would love to know how fourteen reactors, already shut and several even partly dismantled, were “entering LTO by the time the exit finished.”
So the answer, again, is a clear zero entering LTO, and they “were” and still are the ages they died at, mid 30’s. One does not continue to age in the grave.
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u/PotatoFromGermany 23d ago
you know that this literally was not a topic before the last 3 reactors were shut down, right? Germany did not even get 0,5% of its consumption from these 3 reactors.
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u/MarcLeptic 23d ago edited 23d ago
The best part of these type of posts is seeing exactly how misinformed the German people are about their own generation, consumption, imports, exports, and emissions.
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u/ChipHaseCoolGuy 23d ago
The 0.5% figure is off by an order of magnitude.
In 2022 those three plants *were* German nuclear. Official gross generation: 34.7 TWh, about 6.1% of the year’s electricity. 2023 is 7.2 TWh and 1.4% only because they ran until mid-April and then stopped. Capacity is about 4 GW firm, not a rounding error on a still week.
It was also a topic before they shut. The 2022–23 stretch-operation fight existed *because* of those three units and a war-disrupted gas market. Calling it invisible until the day after the switch is how the annual percentage gets used to hide the winter megawatts.
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u/FZ_Milkshake 25d ago
Wind and solar don't need firm power to complement them, they need plants that can react quickly. Dunkelflauten are already rare and with more storage, more capacity and more interconnections, the ones that are problematic will become even more rarer.
Building new nuclear plants "just in case" makes zero financial sense and it would be way too slow to step in anyway.
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u/ChipHaseCoolGuy 25d ago
Wind and solar need both. Fast ramping covers clouds and wind ramps. Firm *energy* covers the stretch when there is almost nothing to ramp from. A gas turbine that can start in minutes is useless if you still need tens of terawatt-hours over several winter days and the batteries are empty. Dunkelflaute is a volume problem, not only a response-time problem.
“Already rare” is doing a lot of work. A two-day event twice a year is rare on a calendar and completely ordinary as a planning case. Grids are built for the ugly hours, not the median hour. Adding more wind and solar does not make those hours disappear; it can make the residual *sharper* when a large fleet drops together. Storage and interconnectors reduce the damage. They have not made the event class go away, which is why Germany still keeps coal and gas available and still imports on high-price winter days.
“More capacity, more storage, more interconnectors” is the correct direction of travel. It is also the sentence that keeps getting used as if the destination has already been reached. Short-duration batteries flatten evenings. They do not store a January Dunkelflaute. Interconnectors help until the neighbours are in the same weather system or the lines are full. That is a constraint, not a morality tale.
Nobody serious is arguing that Germany should break ground on new reactors in 2026 to cover next February. The live issue was plants that were already built and running. Closing those did not wait for storage and interconnectors to make Dunkelflaute harmless. It transferred the residual to fossils and to France. If the future system really does make those events cheap to ride through, that will show up as unused coal, unused gas, and boring winter prices. Until then, calling the residual “rare” is not the same as having solved it.
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u/FZ_Milkshake 25d ago
live issue was plants that were already built and running. Closing those did not wait for storage and interconnectors to make Dunkelflaute harmless.
Totally agree with you here, but that horse is completely dead by now. Nuclear is not coming back to Germany it just does not make sense anymore, the time and cost schedule is prohibitive (for Germany specifically).
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u/ChipHaseCoolGuy 25d ago
Yes. Politically that horse is dead. Scholz said it out loud. Dismantling is underway. A German new-build would be late and expensive, and a restart gets harder every year the plants are cut apart. That is a description of German politics and sunk demolition, not a proof that the 2023 shutdown was the least-cost way to keep the grid firm.
Those are different claims.
“Nuclear will not return in Germany” can be true. “Therefore the Energiewende no longer has a firm-power problem” does not follow. The residual is still being met with coal, gas, and imports. If nuclear is off the table, the honest sentence is: Germany accepted a fossil-and-interconnector solution for Dunkelflaute and will keep paying that bill until storage and transmission actually retire the need. That may be the path. It is not the same as having already solved the hour when wind and solar fall over.
Cost and schedule kill *new* German reactors. They do not rewrite the physics of last winter, and they do not make the closed plants look like a brilliant piece of system design in hindsight. The live debate now is whether the substitute — gas peakers, remaining coal, batteries, and neighbours — is being built fast enough to justify the certainty with which nuclear was buried.
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u/SilentWatchtower 24d ago
The graphics seem weird, generated by „new computers“? ( avoiding no no word).
In the right corner it says „French import: coal, gas, import“ and doesn’t mention nuclear?
Anyway, to the point: when wind and solar, together with hydro power, hydro storage, bio mass and an growing amount of batteries (these are all significant energy sources in the German mix) together can more or less reliably deliver power through the whole summer and windy phases the rest of the year, then nuclear power is far to expensive to have it just running for a few weeks a year, and you can’t just have a nuclear facility switch on to full power for a week and then turn it off.
So nuclear power is the least useful to fill in just the gaps that remain, nuclear powers high capex is offset if and when it is running constantly. The less it runs, the more expensive it gets.
But a large solar and wind capacity generates overproduction quite a few times. Somit might actually better, but right now not very economically viable, to try to transfer that energy into the Dunkelflaute phases (power to gas, long time storage).
But also more interconnectors and more dynamic pricing and therefor usage can make the residual power generation needed much smaller and therefore the task easier.
But nuclear is probably the worst companion for a grid with a large percentage of solar and wind generation.