Model step
Low-light threshold
Lowest plane-of-array irradiance counted
Inputs used: Apply the low-light threshold, Threshold on the plane global
What it is
The low-light threshold is a floor on the global irradiance of the module plane. A timestep whose plane irradiance falls below it is treated as dark: all of its light on the plane is set to zero before the horizon, shading and reflection steps. Such timesteps come at dawn and at dusk. A simulation uses a threshold because at a few watts per square metre the array delivers almost no power, and the transposition models are least accurate with the sun near the horizon.
Options
- Threshold on the plane global: plane irradiance below a set value, 7 W/m² by default, counts as zero
- No threshold: every timestep keeps its plane irradiance, however small
API
options.use_glob_inc_threshold = true | false, options.glob_inc_threshold_wm2