Temperature-corrected Performance Ratio
PR with the weather’s heat penalty removed, so real losses stand out.
Temperature-corrected PR adjusts standard Performance Ratio for module temperature, removing the seasonal efficiency loss caused by hot cells. Because raw PR sags every summer purely from heat, the corrected version is what reveals genuine, recoverable losses — and is the fairer basis for comparing months or benchmarking sites in different climates.
Definition
A silicon module loses roughly 0.3–0.45%/°C above 25°C. Standard PR therefore drops in summer even on a perfectly healthy plant. Temperature-corrected PR (PR_temp, per IEC 61724) applies the modules’ temperature coefficient to normalise output to a reference cell temperature, so what remains reflects soiling, degradation, downtime and wiring losses rather than the season.
Formula
PR_temp = PR ÷ [1 − γ × (T_cell − T_ref)] (γ = module temp. coefficient)
Typical range
Temperature-corrected PR is flatter across the year than raw PR and typically sits a few points higher in summer. A persistent gap that the temperature correction does not close is the recoverable-loss signal.
Why it matters
Without the correction, every plant looks like it degrades each summer and recovers each winter, masking real faults under a seasonal sawtooth. Performance guarantees and like-for-like site benchmarking depend on the temperature-corrected figure; arguing a warranty or O&M SLA on raw PR invites a weather counter-argument.
How NuraVolt tracks it
NuraVolt applies each module type’s temperature coefficient using measured or modelled cell temperature, reports both raw and temperature-corrected PR, and isolates the residual loss after the heat penalty is removed — so a real fault is no longer hidden inside the summer dip.
Frequently asked questions
See also
The headline efficiency number for a PV plant, independent of weather.
Energy produced per unit of installed capacity — the cross-site comparator.
Actual generation measured against a physics model of what the plant should have made.
Another loss bucket that can mask itself in raw PR.
See this on your own plants
NuraVolt turns your SCADA and BMS data into early fault detection, degradation-aware BESS analytics, and audit-ready reporting. A fixed-scope audit shows you what we’d find on your portfolio.