The problem: capacity charge and power peaks
A plant with 5 MW of contracted capacity and a 4-hour production peak pays a capacity charge calculated from consumption during peak hours. Limiting draw by 1.5 MW during those hours cuts the annual capacity charge by several hundred thousand PLN while also removing the risk of exceeding contracted capacity.
How BESS peak shaving works
The EMS measures consumption at the metering point and discharges the storage system whenever instantaneous power exceeds the set threshold. Charging takes place during the night trough or from surplus generation of an on-site PV installation. A 2 h (0.5C) configuration covers a typical single-shift peak profile.
Sizing parameters
| Contracted capacity | BESS power | Capacity | 20 ft containers |
|---|---|---|---|
| 1–2 MW | 0.5 MW | 1 MWh | 1 |
| 2–5 MW | 1 MW | 2 MWh | 1 |
| 5–8 MW | 2 MW | 4 MWh | 1–2 |
| 8–15 MW | 5 MW | 10 MWh | 2–3 |
Cost and payback
A 1 MW / 2 MWh block requires a capital outlay of PLN 1.9–2.6 million. Combining the effects of capacity charge reduction, arbitrage and avoided connection upgrades, the simple payback period is typically 5–8 years, shortening to 4–6 years with additional DSR participation.
Scope of delivery
- Technical design, power and capacity sizing based on a 15-minute load profile
- Liquid-cooled 20 ft container, PCS, transformer, MV switchgear
- EMS integrated with the plant's higher-level control system (Modbus TCP / OPC UA)
- Fire safety approvals, commissioning documentation, start-up and operator training
- O&M service with a guaranteed 24-hour response time