Derating factors

Different derating factors are available in SolarPlus in the “Solar & Battery designer” view:

Field	Use case
Solar export limit	To limit the export to the grid (leave this field blank if there’s no export limit; a '0' value input will stop all export to the grid)
Soiling (dirt/dust)	Entered as a % factor (i.e., 95% means a 5% reduction in the annual energy output)
Grid availability	Entered as a % factor (i.e., Grid availability of 99% means there are grid outages / blackouts 1% of the year) Creates random times when the Grid is not available due to blackouts. During a blackout: If there is no battery, or grid configuration is Hybrid only (no backup), then loads = 0 (power outage), and solar export = 0. If there is a battery, and grid configuration = backup (internal or external), then loads will be powered from solar and battery. Solar and battery export = 0. If there is a battery and grid configuration = backup, but the battery has been depleted, then, loads = 0 (power outage) and solar and battery export = 0.
Surface reflectance	Called as albedo factor - used for system designs with bifacial panels. Select the required surface type based on its albedo factor
Solar access (shading / shade derating)	Entered as a % factor for each month (i.e., 95% in January means a 5% reduction in energy output for the month)

Factor	Description	Data Source	Normal range
Global horizontal irradiance	How much solar energy falls on a flat surface at the site location	MeteoNorm weather data
Irradiance on an inclined plane	How much solar energy falls on the surface at the tilt angle and azimuth that the array has been set to.	MeteoNorm weather data, and the surface setting on the design page.
Shading	Losses caused by near (trees and buildings) and far (mountains) object shading	Can set a default value in Business Settings > Quote preferences. Can set a site-specific value in the Solar & Battery Designer page
Soiling	Lost production due to dirt on the panels	Can set a default value in Business Settings > Quote preferences. Can set a site-specific value in the Solar & Battery Designer page	-1 to -10%
Transmittance	The amount of solar energy that passes through the glass/plastic of the PV module	Based on whether the module has anti-reflective coating (specified in datasheet and recorded in the Product Library)	-1 to -3%
Array converted energy	How much of the available solar energy is converted to electrical energy.	Based on the datasheet values of each panel, and calculated using Cubas equivalent cell method
Cell temperature loss	When PV cells get hot, they are less efficient.	MeteoNorm air temperature records for the site Mounting method of the PV module (specified in BoS section on Design page) Module datasheet values
Tolerance	loss/gain associated with manufacturer’s specifications	Datasheet value	0 to 5%
Mismatch	losses due to panel power mismatch. lower for micro-inverters and optimisers	Can be adjusted in BoS section on Design page	-0 to -2%
DC cable & Connector	Voltage drop losses	Based on cable specs in BoS section on Design page, and array current.	-0.5 to -5%
Inverter clipping	Losses when the PV Array DC output power is higher than the Inverter AC max power (oversizing)	Inverter datasheet value, compared with PV output
Inverter efficiency	Losses from MPPT and converting DC to AC	Inverter datasheet value	-2 to -5%
AC cable losses	AC Voltage rise losses on the Inverter Feed cable. (does not consider sub-main,	Based on cable specs in Solar and Battery Designer, and Max inverter current, and export limit.	-0.5 to -3% (ideal)
System efficiency	The total system efficiency	All de-rating factors above.	75-85%