Insolation

Insolation is the amount of solar energy received by a surface (irradiance) over a specific period of time time. The cumulative and retrospective nature of this metric makes it essential to analyze the performance of solar PV assets over time.

The Analysis module allows you to view insolation values for specific time periods for the entire portfolio, selected sites, and individual devices (inverters).

Tip: The difference between irradiance and insolation is similar to the difference between power and energy. Irradiance and power are static values, while insolation and energy are measured over time.

Insolation calculation

To calculate insolation, GPM Horizon processes the irradiance values available in the Monitor module, aggregating them at an hourly level.

Remember: The data quality of the irradiance measurements depends on the correct installation and maintenance of the sensors and related hardware. The relevant documentation is the property of third-party providers, who are also responsible for the accuracy and validity of the information provided. For more information, contact your GPM representative.

To calculate the insolation, GPM Horizon uses the following parameters and variables:

Irradiance (W/m²).
Timestamps per hour (h): number of data points recorded per hour by the device (five-minute intervals).
Note: This divisor normalizes the irradiance to account for the number of measurements taken within an hour, providing an average value.

GPM Horizon calculates insolation using the following formula:

$Insolation (kW / m^{2}) = \frac{Irradiance}{Measurements per hour / 1000}$

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.

Note: Since irradiance is measured at the level of entire sites, the values for individual devices and for the site are usually the same.


Level	Aggregated variables
Portfolio	Sum of data from all sites.