The summer power cost less than nothing

Thirteen O'Clock, Minus Two Hundred and Fifty

Sunday 11 May 2025 was a fine spring day across Germany: clear skies, mild temperatures, and almost nobody at work. At midnight the day-ahead auction for the German-Luxembourg bidding zone had cleared at a perfectly ordinary €97.80 per megawatt-hour. At 08:00 the price was still positive, just: €4.96. Then the sun took over. At 09:00 the price crossed zero, to -€0.10. By 10:00 it was -€12.02; by 11:00, -€51.95. At 12:00 the auction cleared at -€212.82, and at 13:00 it reached -€250.32 per megawatt-hour, at the time the deepest negative hourly price the German day-ahead market had ever produced. The hour from 14:00 cleared at -€230.98, then -€110.06, then -€18.52, then -€0.08. At 18:00, with the sun finally weakening, the price snapped back to +€85.96, and by 20:00 the same market that had been paying buyers €250 to take electricity seven hours earlier was charging them €124.86 for it.

Nine consecutive hours below zero. A price swing of €375 within a single Sunday. And underneath it, an almost embarrassingly simple physical fact: in the early afternoon German solar output peaked above 43 GW while the whole country was consuming only about 39 GW. At 13:00, solar alone was generating roughly as much as Germany was using. Everything else on the system (every wind turbine, every biomass plant, every lignite unit that could not or would not stop) was surplus.

Nine Hours Below Zero: German day-ahead prices, Sunday 11 May 2025

€/MWh

DE-LU bidding zone, hourly clearing prices. 13:00 cleared at -250.32 €/MWh, the German day-ahead record low at the time.

Data table (24 rows)

Nine Hours Below Zero: German day-ahead prices, Sunday 11 May 2025 (€/MWh). Source: Source: EPEX SPOT day-ahead auction results via Bundesnetzagentur | SMARD.de, retrieved through energy-charts.info (Fraunhofer ISE), CC BY 4.0
Period	Day-ahead price (DE-LU)
00:00	97.80
01:00	95.10
02:00	94.51
03:00	95.42
04:00	95.39
05:00	95.45
06:00	87.61
07:00	65.76
08:00	4.96
09:00	-0.10
10:00	-12.02
11:00	-51.95
12:00	-212.82
13:00	-250.32
14:00	-230.98
15:00	-110.06
16:00	-18.52
17:00	-0.08
18:00	85.96
19:00	117.11
20:00	124.86
21:00	109.55
22:00	98.45
23:00	84.68

Source: EPEX SPOT day-ahead auction results via Bundesnetzagentur | SMARD.de, retrieved through energy-charts.info (Fraunhofer ISE), CC BY 4.0

That Sunday was not an aberration. It was the sharpest point of a pattern that has been compounding for three years. Germany logged 301 negative-price hours on the day-ahead market in 2023, narrowly beating the pandemic-year record of 298. In 2024 the count jumped to 457 hours, five per cent of the entire year. In 2025 it reached 573 hours, a third consecutive record, with nearly half of those hours packed into May and June alone. Spain, which had never cleared a single negative hour in its history before April 2024, blew past 500 hours in 2025. The negative price has gone from curiosity to season.