The month the sun worked for three euros

Three Euros

In May 2025 the average megawatt-hour of Spanish solar electricity sold on the day-ahead market for €2.97. In the same month, the panels delivered 5.2 TWh, more than in any May before it. Two springs earlier, in the second quarter of 2023, the same megawatt-hour had earned €61.33.

Those are not press-release numbers. They come out of Vantage's own database: every day-ahead hour and every measured solar megawatt-hour for the Spanish bidding zone since January 2022, weighed against each other, month by month. And the closer you look, the worse May 2025 gets. On twenty-two of its thirty-one days the fleet's daily capture price was below €5. On ten days it was negative. On the worst of them, Sunday 18 May, the average solar megawatt-hour earned minus €6.93. For ten days of Europe's finest solar spring, the Spanish solar fleet as a whole paid the market for the privilege of generating.

Nothing was broken. The sun shone, the panels converted it, the grid absorbed it, consumers paid almost nothing at lunchtime. Every machine did its job. What failed is the thing nobody watches while the build-out is being celebrated: the price that solar itself is paid. Spain has built the fastest-growing solar fleet in Europe and, in doing so, dismantled that fleet's own revenue faster than any market on the continent. This editorial is the story of that collapse: what our own numbers say about it, where the press numbers are wrong, and what it is now doing to the owners of forty-odd gigawatts of Spanish glass and silicon.