Commercial BESS Peak Shaving & Demand Charge Calculator
Size stationary Battery Energy Storage Systems (BESS in kW & kWh), calculate 15-minute utility demand charge reduction, account for round-trip efficiency (RTE) losses, and compute payback.
Facility Load Profile & Peak Shaving Target
kW
Highest 15-minute monthly billing peak.
kW
Shaves 100 kW off utility demand.
Hours
Typical C&I peak window: 2 to 4 hours.
$/kW/mo
Commercial rate: $15 to $35/kW.
Battery Specs & Financial Parameters
%
AC-to-AC turnkey efficiency.
%
$/kWh
Hardware, inverter, civil, and interconnect.
$/kWh
BESS Sizing Recommendation
100 KW / 254 KWH BESS
Recommended BESS Energy Size
254 kWh
200 kWh usable discharge energy
Inverter Continuous Power
100 kW
0.39C discharge rate
Annual Net Demand Savings
$22,349 / yr
$2,250 / mo gross demand savings
Simple Payback Period
5.1 Years
$114,300 estimated turnkey CapEx
Efficiency Loss & Lifecycle Economics
Daily Recharge Energy Consumed:
232.6 kWh (32.6 kWh RTE loss)
Annual Recharge Electricity Cost:
$4,652 / year (250 business days)
10-Year Cumulative Net Savings:
$109,180 net profit after CapEx
Commercial Demand Charge Mechanics
Grid Engineering
Commercial utility bills bill customers heavily for their peak 15-minute power demand (kW) each month, representing 30% to 70% of total commercial electric bills. Sizing the battery for duration ensures the system discharges throughout the entire peak interval without draining before the utility billing window closes.