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: September 5 – 11, 2026.
The optimal strategy earned €9.55 over the week versus €1.73 for the basic timer — a +453% uplift, projecting to roughly €435 per year for a single 10 kWh battery cycled once per day.
Average temperature was 20.7°C, with 52 hours of strong sunshine (solar ≥ 200 W/m²), average wind 9.5 km/h, and 20.0 mm of rainfall over the week.
Solar irradiance and spot price correlated at r=-0.60 (solar lowers prices), wind at r=-0.31 (wind lowers 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 |
|---|---|---|---|---|
| 2026-09-04 | €0.00 | €0.00 | 0.0 ct/kWh | 25°C · ☀ 0 W/m² · 💨 7 km/h |
| 2026-09-05 | €0.92 | €0.13 | 10.2 ct/kWh | 22°C · ☀ 661 W/m² · 💨 14 km/h |
| 2026-09-06 | €1.94 | €0.33 | 21.6 ct/kWh | 21°C · ☀ 725 W/m² · 💨 10 km/h |
| 2026-09-07 | €1.33 | €0.35 | 14.7 ct/kWh | 21°C · ☀ 565 W/m² · 💨 6 km/h |
| 2026-09-08 | €1.86 | €-0.09 | 20.6 ct/kWh | 25°C · ☀ 699 W/m² · 💨 8 km/h |
| 2026-09-09 | €0.95 | €0.11 | 10.6 ct/kWh | 24°C · ☀ 705 W/m² · 💨 11 km/h |
| 2026-09-10 | €1.66 | €0.60 | 18.5 ct/kWh | 17°C · ☀ 354 W/m² · 💨 9 km/h |
| 2026-09-11 | €0.89 | €0.30 | 9.9 ct/kWh | 15°C · ☀ 322 W/m² · 💨 9 km/h |
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