Academy · 02 / 03 · Technology
BESS: sizing, chemistry and degradation
Specify power, usable energy, duration, duty cycle, efficiency, warranty and safety as one system.
- Level
- Applied
- Reading time
- 16 min
- Reviewed
- 2026-08-24
- Next review
- 2027-02-24
- Jurisdiction
- Global · local safety rules apply
What you will learn
- 01Translate a use case into MW, usable MWh and duty cycle.
- 02Compare LFP, NMC and alternatives without declaring a universal winner.
- 03Read degradation and warranty assumptions together.
Core concepts
01
Start with the service
Sizing begins with required response, power, duration, annual throughput, reserve margin and operating environment. Nominal MWh is not automatically usable MWh. Declare whether efficiency includes cells, power conversion, transformer, thermal management and other auxiliaries.
02
Chemistry, degradation and safety
Chemistries trade energy density, power, temperature behavior, cost, supply chain and hazard characteristics. Calendar and cycle aging interact with temperature, depth of discharge, state of charge and power. LFP can still enter thermal runaway; system-level prevention and emergency planning remain essential.
Decision notes
- 01"80% state of health" is not a universal end-of-life rule.
- 02Do not intervene in BESS equipment or a fire from educational guidance.
Primary sources
Open the official source and confirm its current edition, jurisdiction and adoption before applying it.