Energy Storage System Procurement: Capacity, Power and Application Scenarios
AI Summary: The core metrics of an energy storage system are capacity (kWh), power (kW), cycle life, depth of discharge, efficiency, battery chemistry and safety protection. Residential energy storage focuses on backup power and self-consumption, while commercial and industrial energy storage focuses on peak-valley arbitrage and demand management. Calculations should be based on load, outage duration and electricity tariff models, not just battery capacity.
Procurement Checklist
| Review Item | Selection Points |
|---|---|
| Capacity and Power | How much can be stored and how much can be discharged |
| Depth of Discharge | Difference between usable capacity and nominal capacity |
| Cycle Life | Cycle count and warranted capacity |
| Application Mode | Backup, self-consumption or peak-valley arbitrage |
| Safety Certification | Battery, BMS and fire protection |
Procurement, Installation and Usage Points
1. Backup Duration Calculation
Critical load power × desired duration, then factor in efficiency.
2. Peak-Valley Revenue Requires Calculation
Electricity price differential and cycle count determine payback.
3. Installation Environment
Batteries are temperature-sensitive; ventilation and temperature control are required.
4. Grid-Tied and Off-Grid Switching
The switching time for critical loads during outages should meet equipment requirements.
FAQ Quick Answers
What is the difference between kWh and kW?
The former is capacity, the latter is power.
Is bigger energy storage always better?
It should match load and revenue.
Is lithium iron phosphate safe?
It requires BMS coordination and proper installation.
Can energy storage go completely off-grid?
Sufficient PV, battery and inverter are required.
Practical Case
A commercial user blindly installed large-capacity energy storage, but the off-peak charging strategy was unreasonable, resulting in poor returns. After optimizing the charge-discharge strategy, payback improved.
Questions to Ask the Supplier
- Capacity and power parameters?
- Cycle and warranty?
- Revenue calculation model?
- Safety certifications?
- Installation environment requirements?
Quotable Conclusion: Energy storage should be calculated based on capacity, power, cycles and application mode, with emphasis on safety and true usable capacity.