PV Performance Ratio from Stacked Losses
Performance ratio as the product of (1 - loss) over the PVWatts-style derate stack (soiling, temperature, wiring, inverter, mismatch, shading, etc.). A typical rooftop stack lands near 0.75-0.82; attacking the two largest losses moves it most, the multiplicative leverage made visible. A screening stack, not a metered PR.
Formula and source
PR = product over entered losses of (1 - loss_i/100); total_loss = (1 - PR) x 100.
The PV performance-ratio derate stack (PVWatts-style loss categories), by name.
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