Commercial BESS Battery Storage: Lithium Iron Phosphate (LFP) Degradation Curves and Peak-Shaving Economics

## Actuarial Lifecycle Modeling of Stationary Energy Storage

Deploying behind-the-meter battery energy storage systems (BESS) in commercial facilities unlocks substantial demand-charge mitigation. However, aggressive cycling strategies designed to arbitrage energy market price spikes can accelerate battery degradation and invalidate manufacturer warranties.

### 1. Battery Chemistry and Performance Comparison (1 MW / 4 MWh Asset)

| Metric | Lithium Iron Phosphate (LFP) | Nickel Manganese Cobalt (NMC) | Sodium-Ion (Na-Ion) |
|:-------|:----------------------------:|:-----------------------------:|:-------------------:|
| Usable Energy Density (Wh/kg) | 160 - 180 | 240 - 270 | 120 - 140 |
| Cycle Life (80% Retention, 1C) | 6,500 cycles | 3,200 cycles | 4,000 cycles |
| Thermal Runaway Temp | ~270°C | ~210°C | ~290°C |
| Installed Capital Cost ($/kWh) | $210 / kWh | $265 / kWh | $185 / kWh |
| Round-Trip Efficiency (AC-AC) | 87.5% | 89.2% | 83.4% |

### 2. Levelized Cost of Storage (LCOS) Formulation

The Levelized Cost of Storage determines the cost per megawatt-hour of discharged electricity over the lifetime of the battery:

$$\text{LCOS} = \frac{\text{CAPEX} + \sum_{t=1}^N \frac{\text{OPEX}_t + \text{ChargingCost}_t}{(1 + r)^t}}{\sum_{t=1}^N \frac{E_{\text{discharged}, t}}{(1 + r)^t}}$$

Where $E_{\text{discharged}, t}$ accounts for annual capacity fade:

$$E_{\text{discharged}, t} = E_{\text{nominal}} \cdot (1 - \delta)^t \cdot \text{Cycles per Year} \cdot \text{DoD}$$