Yield loss calculation

When your PV system experiences disruptions, technical failures, or curtailment measures, you want to know how much it is going to cost you – quickly. Yield loss data can help you prioritize O&M service interventions, report to relevant stakeholders, and file claims for lost revenue.  

Integration in the ticket system

Since disruptions are linked to loss of revenue, yield loss calculations are integrated into the ticket system. A ticket is required to calculate yield loss.

Examples of disruption are:

• Maintenance

• Power control/curtailment

• Technical issue

You can create a ticket in the following ways:

• Convert an existing alarm into a ticket

• Manually create a ticket

• Use the automation feature to automatically create tickets for yield loss calculations. See Automation.

Calculation models

VCOM provides the following calculation models. All models are based on the measurement of local irradiance and energy with a typical resolution of 5 or 15 minutes. The model you choose will depend on the cause, available data, length of the disruption, and whether or not your system has power control.

Models for disruptions and technical failures

• Reference system

• Reference component

• Linear equation

Models for curtailments

• Flat-rate billing

• Peak billing

• Simplified peak billing

Note

To learn more about using the models via API, see our API documentation.

Calculation models for curtailment

• The calculation models flat-rate billing, peak billing, and simplified peak billing are relevant for curtailments. These models conform to grid feed-in guidelines from the German Federal Network Agency (Bundesnetzagentur) but can be applied to any location, provided the system fulfills the prerequisites.

• You must define the source of curtailment: grid operator, energy trader, manual, or static

  • Manual: Manual curtailment of a system, for example for testing purposes.

  • Static: An external source (for example a grid operator) sends a signal to the data logger, and the energy trader takes no action. The signal rarely changes.

• If your system can be curtailed by both a grid operator and an energy trader, choose either source. The lower setpoint value will be automatically selected.

• For each curtailment event, you can only apply one yield loss calculation method.

Calculate a yield loss based on an existing ticket

Prerequisites

• Revenue and currency are set up. See System revenue.

Steps

1. Navigate to the Tickets portlet.

2. Right-click on a ticket title and select Edit. The details will appear in the Ticket details portlet.

3. In the Ticket details portlet, select the Yield loss tab.

4. Select the desired calculation model.

5. Fill in the required parameters and select Save. For details, see the descriptions of the individual calculation models.

Further actions

Export results

You can export the results of the yield loss as a CSV file.

Visualize yield losses

You can view curtailments in the Power control tab or the Control visualization chart.

Integration into reporting

Yield loss is linked to a ticket and can, in turn, be shown in OpenOffice reports with the values “Lost yield” and “Lost yield (euros)”. The yield loss is recorded in the error protocol both in kWh and in the respective national currency you have set up in the System administration.