KPI Editor: PR/Performance ratio

Last modified: 2026-07-16

The performance ratio is calculated based on the actual generated energy (= system yield), installed DC power, and POAI/Plane-of-array irradiance. It indicates how well the PV system can convert solar energy. Typically, an annual PR value of 75-85% is considered good.

Performance ratio overview

	Name	Description
1	New PR calculation	Create a new PR formula.
2	Main PR	Main PR used in charts and reports.
3	Edit	Edit calculation parameters.
4	View	The formula is read-only if the user is not the creator.
5	Export calculation	Export calculation parameters and data as an Excel spreadsheet
6	Delete	Delete PR formula.

PR formula with all parameters activated

The PR formula from IEC 61724-1 is used. You can adjust the parameters to meet your requirements:

Expand to view formula

PR parameters

The table below describes the parameters of the PR formula:

Expand to view explanation of PR parameters

Parameter	Variable	Description
Source of data for E_feed-in	E_feed-in	This must be a term with the unit kWh representing energy fed into the grid.
Source of data for H_POA	H_POA	Select a source of irradiance: A sensor that is defined as a term with the unit W/m² for irradiance at the module plane. See Terms. Satellite data
Scope of data		Interval during which the PR is calculated. We recommend Irradiance as threshold to exclude irrelevant intervals, as this works better on cloudier days.
Aggregation of data		Select the aggregation method that defines how daily values are weighted in the monthly PR: Based on IEC (default): Calculated from total monthly sums of energy and irradiance. Adjust for energy produced: Days with higher energy yield have more influence on the monthly PR. Adjust for irradiance: Days with higher irradiance have more influence on the monthly PR.
Excluded ticket causes		Choose intervals you want to exclude from the calculation. See Exclude tickets from KPI calculations.
Temperature compensation	C_k γ T_mod T_ref	Enter a Temperature coefficient. Under Source of data for T_mod: Select the data source for the PV module temperature. The temperature source must be defined as a term with the unit °C for module temperature. See Terms. Source of data for T_ref: Choose a reference temperature: T_STC 25° C: Default: Based on standard test conditions for modules. Single value: Based on a single temperature. Monthly distribution: Based on varying monthly temperatures. Sensor: Based on values from a temperature sensor.
Degradation	d	Add the annual degradation rate of your modules. This can be the same rate as for the Yield forecast or a different rate.
Power control	PC	Correct the PR for periods when the system is curtailed by adjusting the expected energy accordingly. Select the source of power control/curtailment: Correction value: Use the technical value calculated by the PPC and sent to the inverters. Setpoint value: Use the external setpoint from the grid operator or energy trader.

Configure a new PR

Prerequisites

You are a premium partner or have purchased the KPI Editor module.
- User group operations or higher
Terms are set up for the following: feed-in energy, irradiance, and temperature.
VCOM receives power control signals.

Steps

Go to System settings > Calculations > Performance ratio.
Select New PR calculation.
Select Edit next to New PR calculation and give your calculation a name.
Edit the parameters to meet your requirements. See PR parameters.
Select Save.

The performance ratio is configured. The formula on the right side of the window will update based on the new settings.

Example: User-defined PR configuration

This user-defined PR example is based on the contractual requirements of a specific system.

Uses the default term E_Z_EVU for feed-in energy
Uses satellite data.
Only considers data between 8 AM and 8:55 PM.
Data aggregation is adjusted for energy: days with higher energy yield have more influence on the monthly PR.
The interval related to the ticket “Grid voltage” is excluded from the calculation.
Temperature changes are taken into account using the default coefficient 0 and the default term for module temperature, T_M0. The reference temperature is the STC standard of 25°.
The active power correction value PPC_P_SET_CTRL_REL is factored into the calculation.

PR chart thresholds

You can define the thresholds for different performance levels (displayed as green, yellow, and red) that are reflected in the PR/Performance ratio chart and PR/Performance ratio – comparison chart:

Portfolio-wide for every system: At the Portfolio-level , go to Portfolio settings > Customization > Design > Chart thresholds.
System-specific for each system separately: At the system-level , go to System settings > Calculations > Performance Ratio > PR chart thresholds.

Troubleshooting: PR not available

Missing KPIs are usually caused by missing data, outages, or low irradiance. Check your data sources and alarms.

To help identify root causes, you can Download a CSV file to view the raw data used for the PR calculation (daily aggregation). The same root causes will affect system availability as well.