Symptom
Gradual production recovery
- ID
symptom:gradual-production-recovery- IRI
https://solarlattice.org/kb/symptom/gradual-production-recovery- Status
- active
After a snow event, production falls sharply and then comes back slowly as the snow melts or slides off the modules. The plant can be available and the irradiance sensors can show good resource while covered modules still make little current. Snow that clears only partly makes string and substring currents uneven, so the loss may not match how much snow you can see. Begin with timestamped weather data such as snowfall, snow depth, temperature, wind and irradiance, and line it up with the SCADA production residuals and any camera, drone or field views of snow cover. Compare the measured recovery curve with the energy model's snow-loss assumptions; if a site clears more slowly than modeled, it may need a revised snow-loss factor even when the equipment is fine. Do not put every winter residual down to snow: first filter out cold-weather inverter behavior, clipping, curtailment, trackers frozen in stow, iced sensors and albedo effects. Track winter residuals separately from ordinary soiling losses.
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- sentence 7: support check: partial - Mitigation says track winter residuals separately from generic soiling; the statement says 'ordinary soiling', which is equivalent, but it's framed as a mitigation not a general rule.
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Claims
observed_as
c1 drafted · lead
Snow-aligned production residual
Production falls abruptly after snowfall, then climbs back gradually as snow melts or slides off. Line the residuals up against timestamped snowfall, snow depth, temperature, wind and irradiance data.
review note: support check: partial - Passages support abrupt drop then gradual recovery and aligning residuals with weather data, but not the specific signal patterns (rising over days, POAI usable while AC below expected as stated), though the latter is loosely implied.
c2 verified · fact
Snow cover in imagery
Camera, drone or field observations of module snow cover, checked against the production residuals during the recovery period.
verified by: review-workflowverified on: 2026-10-20review note: support check: partial - Passages mention camera/drone/field observations of module cover aligned with residuals, but not specifically checking during the recovery period.
c3 drafted · lead
String current below average
While snow partly clears, current becomes uneven across strings and substrings, so the loss does not always scale with the visible snow-covered area.
review note: support check: partial - Uneven current across strings during partial clearing is stated, but nothing about string currents staying below average or the specific channel.
Referenced by
Data