Irradiance

Irradiance is the amount of solar energy received by a surface per unit area (for example, square meters). For photovoltaic (PV) systems, this variable is measured plane of array irradiance (GPOA) provided by sensors (pyranometers or weather stations).

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.

The Monitor module provides real-time irradiance values for the entire portfolio, selected sites, and individual devices (inverters).

The values for irradiance are used to calculate insolation, which is the amount of energy received by a surface over a specific period of time.
Note: For more information, see the Insolation section.

Irradiance calculation

GPM Horizon refines the raw measurements through a process of data cleansing to provide accurate and relevant values.

  1. Remove 5-minute measurements that fall out of range (0W/m2-1400 W/m2).

  2. Remove anomalies (readings with values equal to zero when other sensors provide values higher than zero).

  3. Remove missing readings (null values).

  4. Calculate the 75th percentile of all the valid irradiance measurements.

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
Site

  • Average of device-level data for each variable (when selecting or grouping devices).
Portfolio
  • Average of all pl-level data for each variable.
Time Aggregated variables
Less than daily
  • Average of values for all five-minute intervals within the selected time period.
Daily
  • Average of values for all five-minute intervals within the selected day.
Multiple days
  • Average of values for all five-minute intervals within the selected time period.