Monthly production micro-inverter report — exact value
Monthly grid import (peak / off-peak) network operator meter
Monthly balance: production → self-consumption & surplus surplus = estimate
Estimated monthly gain and cumulative total
Yearly summary
| Prod. | Self | Surplus | Avoided | Resale | Total | |
|---|---|---|---|---|---|---|
| Year 1 Sept 2024 → Aug 2025 |
6498.1 | 4067.2 | 2431.0 | €858.18 | €316.26 | €1,174.44 |
| Year 2 Sept 2025 → Aug 2026 (partial) |
5963.1 | 3505.1 | 2457.8 | €739.59 | €319.78 | €1,059.37 |
| Total | 12461.2 | 7572.3 | 4888.8 | €1,597.77 | €636.04 | €2,233.84 |
Calculation method
Year 1: actual surplus = 2,431 kWh paid by the feed-in tariff contract at €0.1301/kWh = €316.27.
Year 2: surplus estimated at ~2,458 kWh (Linky "energy injected" register: 2,457.9 kWh) — under the €9,600/year OA cap.
Gain = self-consumption × €0.211 (peak) + surplus × €0.1301. Self-consumed energy replaces peak-hour purchases.
Self-consumption: a "daily self-consumption baseline" model (13.54 kWh/day in Y1, 12.44 kWh/day in Y2), tuned so the annual surplus matches reality exactly.
Last 12 complete months Aug 2025 → Jul 2026
Before / after installation
Average daily grid import
| Total import | Days | Avg/day | |
|---|---|---|---|
| Before (Jan → Aug 2024) | 10068.0 kWh | 244 | 41.3 kWh/day |
| After (Sept 2024 → 10 Aug 2026) | 26408.0 kWh | 709 | 37.2 kWh/day |
Caveat: seasons and usage (EV charging, heating) differ between the two periods.
ROI
Installation cost: €13,000 (all taxes included).
Estimated gain: ≈ €1,174.44/year (full first year) and €1,143.93 over the last 12 months.
Payback period: 11.1 years (≈ 11.4 years on a rolling basis).
Fixed subscription unchanged: €30.59/month. All-in tariffs: peak €0.211, off-peak €0.1624.
Methodology notes
- Production: official micro-inverter monthly report (total 12,461 kWh). The Home Assistant meter reads 12,330.5 kWh (≈1 % gap — counter reset/timestamping; the inverter values are used).
- Grid import: monthly readings from the network operator (exact). Peak/off-peak split obtained by interpolating Linky indexes (monthly approximation).
- Surplus: Year 1 is exact (paid by the feed-in tariff, 2,431 kWh); Year 2 is estimated from the Linky "active energy injected" register. Monthly self-consumption is therefore an estimate.
- Valuing self-consumption at the peak tariff assumes solar mostly replaces daytime (peak-hour) consumption.
- Tariffs and the resulting economics evolve with the supply contract; page generated on "11/08/2026".