Battery system economics — when does it pay off?
CAPEX structure, typical 4-5 year payback, what AiBEX changes in the equation.
Updated: 2026-05-10
How much does a typical commercial battery cost?
According to 2026 prices in Bulgaria, Romania, and Greece, a ~50 kWh useable-capacity installation costs between 5,000 and 15,000 EUR depending on:
| Factor | Impact |
|---|---|
| Battery module manufacturer | LFP cheaper, NMC more expensive; brand differences ±20% |
| Inverter size (kVA) | Linear scaling |
| Installation complexity | Site access, cable runs, electrical panel rework |
| Region (BG/RO/GR) | RO slightly more expensive due to truck logistics |
| Replacing an old inverter | Sometimes the existing inverter is PV-only and must be replaced |
Typical midpoint for a business site: ~8,000 EUR.
What is the typical payback?
Without AiBEX (B2B energy management platform, aibex.bg) — often 5-7 years with a manually-chosen ToU schedule. With AiBEX — typically 4-5 years, because the optimization extracts more value from the same hardware.
Where does the money in payback come from?
Three sources:
- Time-shift (arbitrage) — buy cheap at night, use during the day. This is the first and largest source.
- PV self-consumption — if you have a photovoltaic system, the battery stores the surplus and uses it instead of selling at the low feed-in price.
- Peak shaving — avoiding heavy tariff periods (typically 18:00-21:00 in BG).
AiBEX vs manual ToU schedule
Without AiBEX, most customers set a static ToU schedule in the inverter:
- Charge from the grid 02:00-05:00, discharge 18:00-21:00.
This works until:
- Prices change (a cold-snap day → peak at 8:00, not 18:00)
- PV generates unexpectedly (cloudy afternoon → battery doesn’t fill from PV)
- Sensors show that SoC is lower than expected
A static schedule doesn’t react. A dynamic plan reacts every day.
| Metric | Static ToU | AiBEX dynamic |
|---|---|---|
| Daily savings | 100 EUR (baseline) | 130-140 EUR (+30-40%) |
| Payback | 7 years | 4.5 years |
| Reaction to a cold snap | No | Automatic |
| Customer effort | Initial setup | Zero after install |
What is the AiBEX value ceiling?
The subscription never exceeds 5-10% of saved money. If optimization doesn’t add enough value for your profile — we stop billing. This is a guarantee, not PR.
What happens when the battery ages?
Battery cycles degrade capacity by ~2-3% per year under proper management (which AiBEX provides). After 10-12 years, useable capacity falls to ~70%. By that time you’ve already paid back the investment many times over.