Performance Ratio

The performance ratio (PR) expresses the ratio between the actual and the expected energy production of a device or plant. This allows you to assess the efficiency and effectiveness of the conversion of solar energy under real operation conditions, compared to the theoretical potential of plants or devices.

The system can calculate the PR at every level of the portfolio, down to individual devices. It is also possible to calculate the combined PR of groups of plants or devices.

The PR is expressed as a percentage, and is calculated using the following formula:

$PR (%) = \frac{AC Energy (kWh) \times 100}{(Nominal DC Power \times Insolation)}$

Where the denominator calculates the theoretical maximum AC Energy output of the system, operating at 100% efficiency under the given insolation conditions.

PR formula elements

Note: For detailed information, click on an element to navigate to its corresponding section.


Element	Description
AC Energy	Actual output of AC energy over a given period.
Insolation	Amount of solar energy received by the plant or the inverter [kWh/m²].
Nominal DC Power	Theoretical maximum power output at 100% efficiency. For inverters, this parameter is defined by the manufacturer of the device.

Aggregation methods

At each level of the portfolio, GPM Horizon aggregates and ponders the data used for the calculation, to provide relevant metrics at each level while preserving accuracy and reliability.


Level	Aggregated variables
Device	Device-level data is used directly to apply the formula.
Site	Insolation value of each individual device is weighed by nominal DC power. Sum of device-level data is used as the variable for the equation.
Portfolio	Insolation value of each individual device is weighed by nominal DC power. Sum of device-level data is used as the variable for the equation.