Mitigation
System-level degradation modeling
- ID
mit:system-level-degradation-model- IRI
https://solarlattice.org/kb/mit/system-level-degradation-model- Status
- active
System-level degradation modeling means putting the degradation of the whole plant into the performance model, not just the nameplate degradation rate of the modules. It addresses System Degradation vs Module Degradation. Modules age at different rates, and the weaker ones can limit the current of the strings or substrings around them. Because of this mismatch, plant energy can fall faster than the average module's power loss, even while the average module is still within warranty. The model should include the spread between modules and the mismatch loss this spread adds at the circuit level. Where possible, refine the assumption with site measurements, module technology, warranty terms, and IV curve or string-level data. Use field results to update long-term energy forecasts. Some module-level power electronics can reduce the added mismatch loss. Measuring degradation losses accurately takes more than two years of data.
Claims
degradation_rate
c1 verified · fact
nominal 0.1 PERCENT-PER-YR
Conditions: Allowance that some independent engineers add on top of the module degradation rate to cover mismatch when modules degrade at different rates; a modeling allowance, not a universal rule
Extra system-level loss per year on top of module degradation, not a module degradation rate by itself.
verified by: joshuahamsaverified on: 2026-10-20review note: reviewer: the compiler-flagged conflict is a different scenario or technology, not disagreement
c2 verified · fact
nominal 0.5 PERCENT-PER-YR
Conditions: Default module degradation to assume for new crystalline silicon products when the manufacturer gives no value; current rates are often of this order
verified by: joshuahamsaverified on: 2026-10-20review note: reviewer: the compiler-flagged conflict is a different scenario or technology, not disagreement
c3 verified · fact
nominal 0.5 PERCENT-PER-YR
Conditions: Degradation rate assumed by one monitoring platform's performance waterfall; faster or slower degradation is shown as a positive or negative loss
verified by: joshuahamsaverified on: 2026-10-20review note: reviewer: the compiler-flagged conflict is a different scenario or technology, not disagreement
Referenced by
Data