Free tool
Free peak-shaving battery calculator
Estimate the battery size and payback for cutting a commercial site's peak charges — from four numbers, or from your own load profile. Free, no account, nothing uploaded.
Short answer: a battery cuts the peak charge by the kW it shaves × the €/kW rate, every month. Size it as shaved kW × peak duration ÷ ~0.95. With a €450/kWh battery, shaving 60 kW for 2 hours at €8/kW/month costs about €57,000 and saves about €5,800 a year on peak charges alone — a payback near 10 years before energy savings, solar or a connection limit enter the picture.
Estimate130 kWh / 60 kW
- New peak
- 340 kW
- Peak-charge savings
- 5760 € / year
- Investment
- 56.842 €
- Simple payback
- 9,9 years
A rough estimate: it assumes every peak looks the same and counts the peak charge only — no energy savings, no solar, no ageing. Upload a load profile for a sized answer, or run the full analysis.
Run the full analysis — first one freeYour tariff, the bill rebuilt against the invoices, sizing and a PDF report.
Questions
- How big a battery do I need to cut my peak?
- Roughly the power you want to shave times how long the peaks last, divided by the discharge efficiency: shaving 60 kW for 2 hours needs about 126 kWh usable. Peaks that last longer need proportionally more energy, so a load profile gives a far better answer than a rule of thumb.
- What does peak shaving save?
- The peak (demand) charge on the network part of the bill: the shaved kW times the €/kW rate, every month it holds. Energy costs rise slightly, because charging and discharging lose some energy.
- Is this estimate enough to buy a battery?
- No. It is a first look. A feasibility study rebuilds the real bill from 12 months of 15-minute data under the site's actual tariff, simulates the battery through the year and accounts for ageing and replacement. Zorowatt's Workspace does that; the first analysis is free.
- Does my data leave my browser?
- No. The calculator reads the file and runs the simulation in your browser. Nothing is uploaded or stored.