Record solar takes the German spark negative

German solar averaged 18,761 MW on Sunday 2 August, the highest daily mean of the window, and residual load fell to 15,382.9 MW, its window low⁠¹. German day-ahead averaged 103.18 EUR/MWh that day with one print at minus 4.77, and the clean spark spread, the margin a gas-fired plant earns after buying its fuel and its carbon permits, ran robustly negative across the full efficiency band, minus 18.48 to minus 7.86 EUR/MWh⁠². Wind peaked at 20,525 MW on the same day, at 21:30 UTC.

That answers the question this desk left open on 31 July, which asked whether the spread would hold positive through a return of German wind above 15 GW, or reverse inside a single session as it had on 27 July. It reversed. Wind above 20 GW did not hold the sign positive; the solar mean and the residual load left behind it moved with the negative prints, which is the variable the 31 July correction to this desk's own wind-only framing named as operative. One day does not settle the mechanism, but it does what two prints six days apart could not, and it does it on a high-wind day.

Monday 3 August ran the other way on price. German day-ahead averaged 127.24 EUR/MWh across 88 of the day's 96 quarter-hourly prints, and the spark spread ran robustly positive, plus 5.58 to plus 16.20⁠³. No mechanism for that reversal can be read off the generation data, because the 3 August series available to this desk covers the morning only⁠⁴. A morning window excludes the midday solar peak by construction, so no solar, wind or residual-load daily mean can be computed for 3 August, and this desk will not attribute Monday's positive spark to a fall in solar until the full day publishes.

1 August carries no claim in either direction. Run the same arithmetic across the observed TTF range of €55 to 58 and the full efficiency band, and that day straddles zero at plus 8.60 to minus 2.02. Method is unchanged from 20 July so the series stays comparable: an efficiency band of 55 to 58 per cent, 0.2 tonnes of CO2 per MWh, and spark equal to power price minus TTF over efficiency minus EUA times 0.2. Every spark figure here comes from this desk's own arithmetic, not from an exchange settlement print.

The fuel and carbon legs come from a single 3 August aggregator quote, TTF at 57.71 EUR/MWh and EUA at 81.04 EUR/tonne⁠⁵⁠⁶, applied across all three days because no daily series was obtainable and both ICE and EEX were unreachable. Carbon contributes little of the resulting uncertainty, sitting inside the €79.4 to 82.0 band it has held for a fortnight; the gas leg carries it. Earlier prints stand as published, minus 0.52 to plus 5.03 on 30 July and plus 23.58 to plus 29.13 on the morning of 31 July, when German gas-fired output was climbing back into competition with the caverns for prompt molecules.