HOMER Knowledge Base
How do I estimate the lifetime of a battery component in HOMER?
How do I estimate the lifetime of a battery component in HOMER?
To begin, fill out the Depth of Discharge (%) vs Cycles to Failure table on the "Cycle Lifetime" tab of an ASM battery's page in the Library. If you do not have this data for your battery, you can copy the "Generic 1kWh Li-Ion [ASM]" component in the Library and use that lifetime curve data as a starting point:
In HOMER, the degradation limit sets the percent of cumulative degradation at which the battery is replaced. Once the data is entered, click "Recalculate" and HOMER will automatically calculate the Fitted A and Fitted beta values using the equation listed.
The Estimated Lifetime throughput in kWh is also calculated from the cycling data. The Estimated Lifetime Throughput is used to calculate the estimated storage wear cost, which is used for dispatch optimization. Actual lifetime throughput and actual wear cost depends on battery use during simulation.
To begin, fill out the Depth of Discharge (%) vs Cycles to Failure table on the "Cycle Lifetime" tab of an ASM battery's page in the Library. If you do not have this data for your battery, you can copy the "Generic 1kWh Li-Ion [ASM]" component in the Library and use that lifetime curve data as a starting point:
In HOMER, the degradation limit sets the percent of cumulative degradation at which the battery is replaced. Once the data is entered, click "Recalculate" and HOMER will automatically calculate the Fitted A and Fitted beta values using the equation listed.
- N = Number of cycles to failure
- Fitted A = degradation per 100% DOD cycle (multiply by 100 to get percentage)
- Example: 0.00014423*100 = 0.014423% degradation per 100% DOD cycle
- Looking for 2% cycling degradation per year? .02/0.00014423 = 139 100% DOD cycles per year
- 20% degradation limit = .2/0.00014423 = 1388 100% DOD cycles to failure
- Fitted Beta tells you how partial cycles impact degradation. Set beta to 1 for a constant kWh of throughput to end of life, linearly dependent on the DOD. Set beta to 0 for a set number of cycles to failure, with no dependence on DOD.
The Estimated Lifetime throughput in kWh is also calculated from the cycling data. The Estimated Lifetime Throughput is used to calculate the estimated storage wear cost, which is used for dispatch optimization. Actual lifetime throughput and actual wear cost depends on battery use during simulation.