For a 10 kWh home battery in Austria, this analysis uses real day-ahead EPEX spot prices (via aWATTar) and Vienna weather (via Open-Meteo) to compare an AI-optimised charge/discharge strategy against a basic time-of-day timer. Period covered: July 25 – 31, 2026.
The optimal strategy earned €10.65 over the week versus €2.18 for the basic timer — a +388% uplift, projecting to roughly €485 per year for a single 10 kWh battery cycled once per day.
Average temperature was 26.2°C, with 79 hours of strong sunshine (solar ≥ 200 W/m²), average wind 9.5 km/h, and 0.2 mm of rainfall over the week.
Solar irradiance and spot price correlated at r=-0.74 (solar lowers prices), wind at r=+0.04 (wind raises prices). These match what you would expect: more renewable feed-in pushes prices down, so the optimal strategy is to charge during high-renewable, low-price hours and discharge in the evening peak.
| Date | Optimal Strategy | Basic Timer | Spread | Weather |
|---|---|---|---|---|
| 2026-07-24 | €0.00 | €0.00 | 0.0 ct/kWh | 17°C · ☀ 0 W/m² · 💨 3 km/h |
| 2026-07-25 | €1.55 | €0.24 | 17.2 ct/kWh | 22°C · ☀ 869 W/m² · 💨 9 km/h |
| 2026-07-26 | €1.51 | €0.13 | 16.8 ct/kWh | 24°C · ☀ 700 W/m² · 💨 10 km/h |
| 2026-07-27 | €1.32 | €0.50 | 14.6 ct/kWh | 24°C · ☀ 676 W/m² · 💨 17 km/h |
| 2026-07-28 | €1.76 | €0.32 | 19.5 ct/kWh | 25°C · ☀ 808 W/m² · 💨 7 km/h |
| 2026-07-29 | €1.82 | €0.44 | 20.3 ct/kWh | 27°C · ☀ 835 W/m² · 💨 9 km/h |
| 2026-07-30 | €1.57 | €0.36 | 17.5 ct/kWh | 30°C · ☀ 829 W/m² · 💨 7 km/h |
| 2026-07-31 | €1.12 | €0.18 | 12.4 ct/kWh | 31°C · ☀ 836 W/m² · 💨 8 km/h |
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