Storage & demand charges

Battery model

Size a battery to shave peak demand, capture the 30% storage ITC, and model the 25-year return — the half of the commercial bill solar alone can't touch.

Building & battery

Annual electricity use (kWh)

Estimated peak demand ≈ 183 kW (at 0.5 load factor)

Peak demand (kW)

blank = estimate

Demand charge ($/kW-mo)

Battery sizing

Power (kW)

Energy (kWh)

4-hr duration

TOU arbitrage spread ($/kWh)

optional; 0 for flat tariffs

Installed cost ($/kWh)

blank = auto by size

Installed cost ≈ $1,050/kWh (auto-tiered by size). Figures are estimates for screening — confirm with a load study.

Year-1 savings

$9,900

demand + arbitrage

Simple payback

16.3 yrs

on net cost

25-yr net savings

$35,762

25-yr ROI

22%

on net cost

Peak shaving

Billed peak

182.6 kW

Shaved

− 55 kW

New peak

127.6 kW

Annual demand-charge savings$9,900

Storage investment

Battery modules — 220 kWh LFP cells, Tier-1	$115,500
Power conversion system — 55 kW bidirectional inverter	$36,960
Enclosure, thermal mgmt & fire suppression	$23,100
Energy management system & controls	$16,170
Installation & electrical integration	$27,720
Engineering, permitting & interconnection	$11,550

Gross storage cost$231,000

Federal storage ITC (30%)– $69,300

Net storage cost$161,700

25-yr model nets out a ~$80,850 cell augmentation at year 13.

Assumptions & basis

Storage sized at 55 kW / 220 kWh (4-hr duration) at ≈ $1,050/kWh installed (C&I turnkey, 2024-25 NREL/BNEF range).
Demand-charge savings = 55 kW shaved × $15/kW-month × 12. Peak shave is limited by battery power, by energy over a 4-hr peak window, and by the building's actual peak.
Standalone storage qualifies for the 30% federal ITC (IRA §48E) plus accelerated depreciation (MACRS, not modeled here). To earn the full 30% the system must begin construction before the 2026 safe-harbor deadline (or be placed in service by 12/31/2027); larger systems must meet prevailing-wage & apprenticeship rules.
No time-of-use energy arbitrage is modeled (flat-rate tariff); add a peak/off-peak spread to include it.
25-yr model (nominal, un-discounted): 2.5%/yr demand-charge escalation, 1.5%/yr capacity fade, and one cell augmentation (~35% of battery cost) at year 13. Installed cost is auto-tiered by size — override it with your actual quote for an accurate net cost.
Resilience / backup-power value during outages is real but not monetized here. Final design confirmed by an engineering load study.