Key performance indicators (KPIs) to include in a Battery Energy Storage System (BESS) contract are critical for ensuring performance, reliability, and contractual compliance. Essential KPIs typically cover operational capability, efficiency, aging, and safety aspects of the BESS. Based on industry insights and technical literature, the key KPIs to consider in a BESS contract are:
Key Performance Indicators for BESS Contracts
- 1. Battery Capacity
– Defines the total amount of energy the battery can store, typically measured in ampere-hours (Ah) or watt-hours (Wh).
– It directly affects the duration the system can supply power, making it fundamental for long-duration applications. - 2. Rated Voltage
– The nominal voltage output, critical for ensuring system stability and proper integration into the grid or facility. - 3. Power Ratings
– Maximum continuous power and peak power capabilities define the system’s ability to deliver energy at different rates during operation. - 4. State of Health (SoH)
– Indicates the current condition of the battery relative to its original state, reflecting degradation over time. SoH is vital for warranty and lifecycle management. - 5. Round-Trip Efficiency (RTE)
– Measures the efficiency of energy storage and retrieval processes, representing the percentage of energy recovered compared to energy input. This KPI is crucial for assessing operational efficiency and economic viability. - 6. Depth of Discharge (DoD)
– Specifies the extent to which the battery can be discharged without compromising lifespan, influencing cycle life and reliability. - 7. Cycle Life and Equivalent Full Cycles
– Represents the number of complete charge-discharge cycles before the battery degrades to a certain level (usually 80% of initial capacity). Equivalent Full Cycles provide a normalized measure accounting for partial cycles. - 8. Availability
– The percentage of time the BESS is operational and ready to deliver power, impacting contractual service levels and penalties for downtime. - 9. Operating Temperature Range
– Ensures the BESS operates within safe thermal limits, which affects safety and performance consistency. - 10. Safety Metrics
– Includes monitoring for thermal runaway risks, fire safety, and adherence to safety standards relevant to battery operation. - 11. State of Charge (SoC)
– Reflects the current charge level relative to total capacity, essential for operational management and preventing overcharge or deep discharge.
Summary Table of Key KPIs
| KPI | Description | Importance |
|---|---|---|
| Battery Capacity | Energy storage amount (Ah, Wh) | Determines supply duration |
| Rated Voltage | Nominal system voltage | Ensures stable power integration |
| Power Ratings | Max continuous and peak power (kW) | Defines delivery capability |
| State of Health (SoH) | Battery degradation status | Affects warranty and maintenance |
| Round-Trip Efficiency (RTE) | Energy in vs. energy out efficiency (%) | Measures operational efficiency |
| Depth of Discharge (DoD) | Maximum allowed discharge without damage | Influences lifespan and reliability |
| Cycle Life | Number of charge-discharge cycles | Predicts replacement needs |
| Availability | System uptime percentage | Relevant for SLAs and penalties |
| Operating Temperature Range | Safe temperature limits | Safety and performance consistency |
| Safety Metrics | Thermal, fire risk, safety compliance | Prevents hazardous events |
| State of Charge (SoC) | Current battery charge level | Operational management |
These KPIs provide a comprehensive framework for structuring BESS contracts, ensuring that performance guarantees, warranties, and operational targets are clearly defined and measurable. Effective monitoring and reporting of these KPIs help in risk mitigation, performance enforcement, and maximizing the asset’s value throughout its lifecycle.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/what-are-the-key-performance-indicators-to-include-in-a-bess-contract/
