On SRL POS and 08.09.2025
Oversupply follows the sun. Shortfall stacks in harder ways.
Oversupply in Germany’s grid is largely a solar story, captured reasonably well by PV forecasts. Shortfall is harder: it appears when wind misses, demand runs high, and reserves are tight — a more tangled mix of drivers. What follows are playful experiments with openly available data, an attempt to test this asymmetry rather than settle it. If you spot mistakes (as I’m sure you will), have suggestions, devastating criticism, or context, please leave a comment or get in touch.
If you are seeking to understand SRL (capacity) prices in terms of weather (forecasts), then you will know that the effects of the sun are more direct than those of the wind, as in Aesop’s fable. A simple linear regression on ENWEX solar forecasts gives a good fit for SRL NEG. But how about SRL POS?
Sun and wind
In the plot below, the top row shows actual prices compared to predictions from simple regressions on ENWEX forecasts.