Yield forecast chart

Last modified: 20 Aug 2025

Chart

View the chart at SYSTEM LEVEL under Evaluation.

In the example, the light blue section of the chart displays the yield forecast.

Basic info

Description

The yield forecast chart compares the system’s actual, normalized energy (= specific yield) with the normalized energy from yield forecasts.

Prerequisites

A yield report is required for the yield forecast configuration. You can obtain yield reports using specialized software, from third-party providers, or from meteocontrol.
You must configure the Specific energy yield and the annual Degradation for at least one yield forecast at SYSTEM LEVEL under System configuration > Calculations > Yield forecast.

Further details

When configuring the yield forecast, you can:

Enter two separate Specific energy yield values for comparison.
Define annual Degradation rates and how they are calculated.
Define the point at which your system is considered profitable.
Enter annual vertical and horizontal irradiance values.
Display the simulated specific yield for the current year and/or the actual specific yield of the previous year for further comparison.

Note

Find further information on the general functions within charts on Evaluations & charts.

Configure yield forecast

Prerequisites

User group Technical customer or higher
Data from at least one yield report

Steps

At SYSTEM LEVEL, navigate to System configuration > Calculations > Yield forecast.
In the Yield forecast tab, enter the Specific energy yield in kWh/kWp provided in your yield report.
Enter the annual Degradation of your modules in % as specified in your yield report or manufacturer data sheet. Specify whether the degradation is linear or exponential.

Tip

Operating years start with 0 for the first 12 months (not 365 days or first year). In other words, degradation is not calculated in the first year because d=1.

Optionally, add a Note. For example, the name or source of the yield report.
Select Save yield forecast.

Further actions

Once you have added the first yield forecast, you can take the following actions:

Edit data for monthly values

Based on the country where you are located and average irradiance values, VCOM will automatically calculate the average specific energy for each month. If your yield report contains more precise data, you can edit the values by selecting Monthly distribution.

Enter a second yield forecast

Enter data from a second yield report under Yield forecast 2 tab. Follow the steps under Configure yield forecast.
Prerequisite: You have completed and saved the first Yield forecast tab.

Enter profitability

Your yield report may indicate a specific energy yield that will ensure your system is profitable. If this information is available, select the Profitability tab. Follow the steps under Configure yield forecast.
Check Display as graphic to display profitability as a data point in the chart.

Enter irradiance and irradiance (horizontal)

If your yield report provides information about irradiance values, enter the information under the tabs, then follow the steps under Configure yield forecast:
- Irradiance: irradiance on the module plane/plane of array irradiance (POAI)
- Irradiance (horizontal): global horizontal irradiance/GHI

Visualize additional data

Note

Yield forecast and Yield forecast 1 are displayed in the Yield forecast chart.
To display the Simulated specific yield and Values of the previous year in the chart as well, select these options in the Additional visualization tab.
The following data points can only be displayed as part of in OpenOffice reports: Irradiance and Irradiance (horizontal)

Troubleshooting: error message for monthly distribution

Problem

When you manually adjust the monthly distribution of values, you get the error message Check your monthly distribution and adjust the misconfiguration.

Solution

The values for the monthly distribution must add up to the total annual value.

Example

If your annual value is 1000 Wh/m², check that the monthly values add up to 1000.