Argus simulation post-processing overview

In this document

This document describes the post-processing stage of the Argus PV simulation engine in Solargis Evaluate. It explains how system-level losses — not captured in the electrical simulation — are applied to produce the final energy yield estimate.

Overview

Post-processing is the final stage of the Argus PV simulation chain, applied after the electrical simulation has produced the AC power output at the grid connection. While the electrical simulation accounts for all physical losses within the power plant components, post-processing addresses system-level factors that affect long-term energy delivery: unplanned and planned outages, weather-related events such as snow coverage, and the gradual degradation of PV module performance over the operational lifetime of the plant.

This stage is important because it bridges the gap between idealized component performance and the practical, long-term energy yield that investors and asset owners rely on for financial planning and performance assessment. The losses quantified here are based on IEC Technical Specification 61724-3 and are reported in the Solargis Evaluate Analysis section and reports. They are not included in the exported Time Series data, but are applied to produce the final PVOUT and Performance Ratio (PR) figures used in yield analyses and long-term projections.

Solargis Evaluate models long-term degradation up to 25 years forward, using simulated historical averages as the baseline.

Processes included in this stage

The following processes are applied during post-processing:

System unavailability losses (internal and external technical events)
Snow losses (Solargis snow loss model)
Long-term degradation (first-year and annual degradation rates)

Post processing

Unavailability and snow losses

System unavailability losses quantify the electricity losses incurred due to the shutdown or power output limitation of the energy system or its components. These losses can be categorized into two main types:

Technical events: Incurred due to internal reasons (equipment failures or scheduled maintenance work) and external reasons (Grid connection issues, curtailment).
Weather-incurred events: Caused by the snow coverage of PV modules.

Default values used in Solargis Evaluate:

Parameter	Default value
Internal unavailability losses	0.5%
External unavailability losses	0%
Snow losses	0%

Note: The implementation of technical losses is based on IEC Technical Specification 61724-3, which outlines energy evaluation methods for photovoltaic systems.

Setting unavailability losses in Solargis Evaluate

Default unavailability losses can be adjusted in the Losses section of the Energy system designer. Snow losses are simulated using the Solargis snow loss model.

Long-term degradation

The performance of PV modules and other components decreases over time, and long-term degradation serves as a measure of this performance reduction. Typically, PV components experience more rapid degradation in the initial years of their lifespan.

Solargis Evaluate models long-term degradation looking 25 years forward into the PV power plant operation. We use the long-term average yearly power production (PVOUT specific and total) and Performance Ratio (PR) from the simulated historical data, and apply the specified degradation rates to these figures to estimate the expected future PVOUT and PR.

Degradation rates

Based on existing in-field experiences from commercial projects, the long-term annual performance degradation for well-manufactured PV modules may be approximately:

0.8% for the first year
0.5% for subsequent years

Note: This assumption includes initial degradation of the modules.

Setting long-term degradation losses in Solargis Evaluate

Default long-term degradation losses can be adjusted in the Losses section of the Energy system designer. You can set:

Degradation losses for the first year
Annual degradation losses for the following years

Simulation outputs

The result of the simulation is the power output of the energy system, referred to as PVOUT. It is quantified both in absolute numbers and as specific PVOUT, normalized to the installed capacity of the power plant.

The simulation results are visualized in numerous charts and tables in the Solargis Evaluate Analysis section. The data is categorized and segregated into different units with a data interpretation guide included for every presented value, making the data easy to understand and interpret. The power conversion losses are specifically quantified and visualized as average yearly figures (including the Sankey diagram shown below), and monthly breakdowns.