The problem: connection capacity limits hub growth
A hub with four 300 kW chargers needs 1.2 MW of power. Upgrading the connection to that level often takes the DSO more than 24 months and costs hundreds of thousands of PLN. A 1–2 MWh storage system solves this problem on the investor's side.
How the power buffer works
The PCS limits grid draw to the contracted capacity value. Any extra power needed during a charging session comes from the storage system, which recharges between sessions. The EMS manages SOC based on a utilization forecast.
Sizing parameters
| Chargers | Peak power | Connection | Storage |
|---|---|---|---|
| 2 × 150 kW | 300 kW | 100 kW | 0.5 MWh / 0.3 MW |
| 2 × 300 kW | 600 kW | 150 kW | 1 MWh / 0.5 MW |
| 4 × 300 kW | 1.2 MW | 300 kW | 2 MWh / 1 MW |
| 6 × 400 kW | 2.4 MW | 500 kW | 3 MWh / 2 MW |
Cost and payback
A 1 MWh storage system with PCS costs PLN 1.0–1.4 million. Upgrading a connection by 1 MW typically costs PLN 0.4–1.2 million and takes far longer — storage wins primarily on time-to-revenue.