Loss model comparison

ID: method:snow-loss-model-comparison
IRI: https://solarlattice.org/kb/method/snow-loss-model-comparison
Status: active
Also known as: snow loss models

Next, compare the measured recovery curves with the snow-loss assumptions in the energy model. If a site clears more slowly than modeled, it may need a revised snow-loss factor even when the equipment works normally. Some monitoring platforms detect snow loss by pattern matching against weather conditions and against how similar systems performed in snow. A heated pyranometer gives the best results because the algorithm needs irradiance data. Published snow models can disagree a lot even when they use the same weather files. At one site, one model overestimated the measured loss and the other underestimated it, so model outputs need to be checked against real site data.

<!-- review notes

sentence 2: support check: partial - Snow loss detection by pattern matching on weather conditions and previously observed similar-system performance, and heated pyranometer for best results because algorithm requires irradiance data are stated; 'best results because' is slightly reworded but essentially present, though 'some monitoring platforms' generalizes a PowerTrack-specific statement. -->

Claims

`produces`

c1 verified · fact Snow-aligned production residual

Measured recovery curves after snow are compared with the energy model's snow-loss assumptions; a site clearing slower than modeled may need a revised snow-loss factor even with healthy equipment.

snow accumulation losses sec=front h=ef48f3c9a102
snow accumulation losses sec=h2 h=cf13e86d6896
snow accumulation losses sec=h6 h=0935b66311ac

verified by: joshuahamsaverified on: 2026-10-20review note: support check: partial - The comparison of recovery curves with snow-loss assumptions and slower clearing needing a revised factor is stated, but the specific signal patterns (POAI present with negative residual, low module temperature aligned with slow melt) are not stated in the passages.

`typical_power_loss`

c2 verified · fact ≤ 42 PERCENT

Conditions: Annual energy loss predicted by the Marion snow model for a few stations within the Arctic Circle; losses are near zero in warmer regions and the Townsend and Powers model predicts far lower losses at high latitudes.

Soiling Losses – Impact on the Performance of Photovoltaic Power Plants sec=4.2.4 h=5ddca0c6f3d8

verified by: joshuahamsaverified on: 2026-10-20review note: support check: partial - Marion model max of 42% for a few Arctic Circle stations, near zero in warmer regions, and much lower Townsend and Powers losses are stated, but 42% is a maximum, not a typical value.

Referenced by

Snow Accumulation Yield Losses detected_by c14

Loss model comparison

Claims

produces

typical_power_loss

Referenced by

Data

`produces`

`typical_power_loss`