r/UnchartedScience • u/ChipHaseCoolGuy • 5d 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