Storage System POC Energy Calculator
Upload the Excel database, fill in parameters, then calculate FAT, SAT, and Year 1-25 energy & efficiency.
How to use (click to view)

Product Overview

  • BESS POC Calculator is a lifecycle energy simulator for utility-scale BESS, solving POC usable energy and RTE estimation from FAT through Year 25.
  • Key features:
    • SOH-based degradation (calendar + cycle aging)
    • Full-chain losses (DC cable → PCS → PCS-T1 cable → T1 → MV cable → T2 → HV cable)
    • MV/HV boundary switch
    • FAT→SAT storage loss
    • Temperature-driven aux correction

Configuration (3 sections)

  • Project Basics:
    • Rated Capacity (per container)
    • Battery Qty
    • Cell Brand
    • Prate (e.g., 0.5P/0.25P)
    • Cycle/day
    • DOD (90–100%)
  • Environment & Logistics:
    • FAT→SAT months (storage loss; 0 ignores loss)
    • Shipping Temp (affects storage loss)
    • Operating Temp (affects aux power)
  • System & Efficiency:
    • PoC = MV (exclude T2/HV cable) or HV (include T2/HV cable)
    • Efficiencies: η_DC_cable, η_PCS, η_PCS-T1_cable, η_T1, η_MV_cable, η_T2 (HV), η_HV_cable (HV)

Core Formulas (per year)

$$ \begin{aligned} \text{Duration} &= \frac{1}{P_{\text{rate}}}\;\text{(h)} \\[6pt] E_{\text{aux}} &= N_{\text{bat}} \times \text{Duration} \times P_{\text{aux}} \\[8pt] E^{\text{dis}}_{\text{DC}} &= \text{SOH} \times N_{\text{bat}} \times E_{\text{rated}} \times \text{DOD} \times r_{\text{DC}} \times \eta_{\text{storage}} \\ E^{\text{chg}}_{\text{DC}} &= \frac{E^{\text{dis}}_{\text{DC}}}{\eta_{\text{DC RTE}}} \\[8pt] \eta_{\text{sys}} &= \eta_{\text{DC cable}} \times \eta_{\text{PCS}} \times \eta_{\text{PCS-T1 cable}} \times \eta_{\text{T1}} \times \eta_{\text{MV cable}} \times (\eta_{\text{T2}} \times \eta_{\text{HV cable}}\;\text{if HV}) \\ E^{\text{dis}}_{\text{POC}} &= E^{\text{dis}}_{\text{DC}} \times \eta_{\text{sys}} \\ E^{\text{chg}}_{\text{POC}} &= \frac{E^{\text{chg}}_{\text{DC}}}{\eta_{\text{sys}}} \\ \text{AC RTE} &= \frac{E^{\text{dis}}_{\text{POC}}}{E^{\text{chg}}_{\text{POC}}} \\[8pt] E^{\text{dis,aux}}_{\text{POC}} &= E^{\text{dis}}_{\text{POC}} - E_{\text{aux}} \\ E^{\text{chg,aux}}_{\text{POC}} &= E^{\text{chg}}_{\text{POC}} + E_{\text{aux}} \\ \text{AC RTE}_{\text{aux}} &= \frac{E^{\text{dis,aux}}_{\text{POC}}}{E^{\text{chg,aux}}_{\text{POC}}} \end{aligned} $$

Symbols

  • \(P_{\text{rate}}\): system power rating (P)
  • \(N_{\text{bat}}\): number of containers
  • \(P_{\text{aux}}\): aux power per container (kW)
  • \(E_{\text{rated}}\): rated energy per container (MWh)
  • \(\text{SOH}\): state of health (fraction)
  • \(\text{DOD}\): depth of discharge (fraction)
  • \(r_{\text{DC}}\): DC ratio
  • \(\eta_{\text{storage}}\): 1 − storage loss (FAT→SAT)
  • \(\eta_{\text{DC RTE}}\): DC round-trip efficiency
  • \(\eta_{*}\): efficiencies of each link; include \(\eta_{\text{T2}}\) and \(\eta_{\text{HV cable}}\) only when PoC = HV

Steps

  1. Fill parameters in the three sections; set PoC boundary correctly.
  2. Click Calculate → view table & charts → download CSV/PNG.
Excel Database (click to expand)
Excel Database
Current file: data.xlsx
Replace Excel (optional)
Project Basics
Charge/Discharge Duration
4.00 h
Boundary & Environment
Efficiencies (input percent numbers, e.g. 99.5)
Efficiency references & diagram (click to expand)

Efficiency references

  • ηDC_cable - DC cable efficiency
    • Location: cable between battery racks and the PCS DC input.
  • ηPCS - PCS efficiency
    • Hardware: Power Conversion System (DC/AC conversion).
  • ηPCS-T1_cable - LV AC cable efficiency
    • Location: cable between PCS AC output and the low-voltage side of T1.
  • ηT1 - Step-up Transformer T1 efficiency
    • Role: boosts PCS low voltage (e.g., 400-900 V) to medium voltage (e.g., 35 kV).
  • ηMV_cable - MV collection cable efficiency
    • Location: collection cable from T1 MV side to the main transformer (T2).
  • ηT2 - Main transformer efficiency
    • Scope: only when POC is on HV side (e.g., 110/220 kV).
    • Hardware: main transformer that boosts site MV (e.g., 35 kV) to grid voltage.
  • ηHV_cable - HV transmission line efficiency
    • Scope: only when POC is at a remote HV point.
    • Location: line from T2 HV side to the final grid metering point (POC).
Efficiency chain diagram
Battery Augmentation Strategy (Optional)
Augmentation #1