Peak Shaving with Battery Storage: Lower Your Demand Charge
A single 15-minute interval sets your demand charge for the whole year. A commercial battery shaves these peaks and lowers your grid fees. Calculate what that means for your business for free with your load profile.
What is peak shaving?
With peak shaving, a battery discharges whenever a site’s load rises above a set threshold. Grid supply stays below that value and the highest 15-minute interval of the year drops. For commercial and industrial customers in Germany with interval metering (RLM), exactly this interval sets the demand charge (Leistungspreis): it is billed on the annual peak load in €/kW.
How much does peak shaving save?
The saving follows directly from the demand charge and the reduction of the annual peak:
Annual saving = demand charge (€/kW·a) × peak reduction (kW)
Example: with an assumed demand charge of €150/kW per year, a battery that lowers the annual peak load by 100 kW saves around €15,000 in grid fees per year.
The demand charge depends on grid operator, voltage level and utilisation hours. An example from a real price sheet (Bayernwerk Netz, medium voltage 2026): below 2,500 utilisation hours the demand charge is €15.86/kW, from 2,500 hours €99.17/kW. Peak shaving therefore pays off most for sites with many utilisation hours.
Demand charge and the 2,500-hour threshold
Utilisation hours are annual consumption divided by annual peak load. When a battery lowers the peak, utilisation hours rise. A site just below 2,500 hours can thereby move into the other price tier: higher demand charge, lower energy price. Whether that pays off depends on the individual case. More in “Battery storage and the 2,500-hour rule”.
How large does a peak shaving battery need to be?
- Power (kW): determines how far the battery can lower the peak. For peak shaving it is usually the more important value.
- Capacity (kWh): determines how long it can sustain that. Short, high peaks need little capacity, long load plateaus considerably more.
- Load profile: peak shaving cannot be sized properly without 15-minute values, because individual intervals matter.
Important for operation: if the battery misses even one peak, the saving for the whole year can be lost. It therefore has to be charged in time and keep a reserve for the next peak. A forecast-based energy management system plans this reserve using load and generation forecasts.
Combining peak shaving with PV and trading
A battery that only shaves peaks sits idle most of the time. Multi-use operation is often more economical: peak shaving together with PV self-consumption optimisation, dynamic electricity procurement or trading spare capacity. Atypical grid usage under §19 StromNEV can also be combined with a battery.
What changes with AgNes from 2029?
Under the AgNes grid fee reform, the Federal Network Agency’s draft determination replaces the demand charge from 2029 with an ordered capacity chosen by the customer. A missed peak then only costs a surcharge on the energy above the ordered capacity instead of a full year’s demand charge. What this means for sizing is explained in “AgNes: What the new grid fee from 2029 means for your battery storage”. Calculate your future ordered capacity with the AgNes calculator.
Calculate peak shaving
With the calculator above you see within minutes which storage power and capacity pay off for your load profile and when the battery pays for itself. For detailed planning, Furo Plan works with your real load profile, manufacturer data, battery degradation and all revenue streams. Try it free for 14 days.
Frequently asked questions about peak shaving
Peak shaving means a battery discharges as soon as a site’s load exceeds a threshold. This lowers the highest 15-minute interval of the year, on which commercial and industrial customers with interval metering pay the demand charge.
The saving is demand charge times peak reduction. At €150/kW per year and 100 kW less annual peak load, that is around €15,000 per year. Calculate your value for free with the calculator on this page.
For sites with interval metering, a high demand charge and short, high load peaks well above base load. It usually pays off most from 2,500 utilisation hours, because the demand charge is considerably higher there.
Then that interval counts as the new annual peak load, and the demand charge saving can be lost for the whole year. That is why good energy management plans a reserve for the next peak based on forecasts.
According to the draft determination, AgNes replaces the demand charge with an ordered capacity from 2029. A peak above it then only costs a surcharge on the energy above the ordered capacity. A battery can still avoid such grid supply, but no longer needs an expensive buffer for the annual peak and has more capacity free for self-consumption and trading.