Energy system statistics, losses, and long-term degradation

PV energy system data

Data sections described in this document are available for PV energy systems only, They are not provided for GTI energy systems.

When you simulate a PV energy system, its data, such as total PV power output, theoretical PV electricity potential, performance ratio, monthly and yearly averages, or a detailed breakdown of losses, will also be calculated. This data is available in the PV statistics, PV losses, and PV long-term degradation sections, respectively.

• The averages and summaries in the charts are always calculated using the data from COMPLETE years only! For example, if you look at a yearly summary chart in December, the calculated data will not include almost a whole year of data starting from January of the same year.

• Specific PV output charts depict data related to your site and technology, and total PV output provides data visualization regarding the actual modules and inverters used in the project.

• PVOUT Specific and PVOUT total do not consider internal and external unavailability, snow losses, or degradation. They provide theoretical values only.

PV statistics

The charts in the PV statistics section provide theoretical PVOUT values only. They do not take degradation losses into account.

This category provides information about your PV system's potential power output and power output statistics based on calculations derived from the Time Series.

It provides valuable insights into your energy system's expected performance variability, aiding in informed decision-making, accurate budgeting, and proactive management to optimize energy production and mitigate risks.

Summary section

• Specific PV Power Output Chart: Informs you about the system's output power calculated from the average power per 1kWp at the given location.

• Total PV Power Output Chart: This shows you the total output of the whole system.

• Both are complemented with a monthly statistics table to view specific monthly parameters.

PVOUT specific, performance ratio (PR), and total PVOUT sections

• PVOUT Specific and PR: Assesses the efficiency of your solar energy system by comparing the actual energy output to the theoretically achievable energy output under ideal conditions.

• Monthly Statistics (PVOUT Total): This represents monthly averages with minimum and maximum PVOUT values for each month.

• Monthly Statistics Table: Offers specific monthly average values.

• Hourly statistics by month: Gives you a visual overview of the average hourly specific/total PVOUT for every month in the Time Series.

• Hourly averages heat map (PVOUT total): Shows total PV power output in the form of a heatmap to spot the extremities quickly.

• Monthly Time Series Chart: Breaks down the averages for each month for every year in the time series.

Depending on the granularity of the simulation (selected data set), you can explore daily, hourly, or 15-minute PVOUT values, respectively. Hover over the chart to view more details.

PV system losses

This section provides your energy system’s expected loss data, further divided into yearly and monthly sections.

The yearly losses

The Loss Diagram offers a visual presentation of your system’s cumulative energy losses (solar and electrical).

Each additional loss is calculated from the previous cumulative loss value rather than the initial total power value. As losses accumulate over time, each subsequent loss is discounted from the remaining power output after previous losses have already been accounted for.

The losses in the Energy conversion and related losses table are also cumulative; hence, they are calculated from the remaining power output after the previous loss has been accounted for.

The monthly losses

The monthly losses are visualized in the breakdown of the energy losses chart, which depicts the percentile of individual loss values and their total accumulation every month.

You can toggle the visibility of each loss by clicking its name in the chart legend. Hovering over the value highlights it on the chart, showing its actual values per month along with the total for the year.

The breakdown of losses shows absolute loss values (non-cumulative).

PV long-term degradation

Long-term degradation charts depict the decline in your system’s PVOUT value, which represents the energy output drops over time. They provide you with insights into how much energy production can be expected to decrease, aiding in financial forecasting and operational planning.

The values are visualized in the PV electricity lifetime production table (also indicating the degradation rate), and are complimented with specific and total PVOUT degradation charts.

How we calculate the losses

The calculation of losses involves a detailed assessment of various factors that reduce the overall efficiency and energy output of the system. For better understanding, here is a short explanation of each loss included in the diagram:

• Shading Losses: Occur due to partial or complete shading of solar panels when obstructions block solar irradiance from reaching them.

• Pollution Losses: Caused by soiling accumulation on solar panel surfaces.

• Angular Losses: Result from sunlight incidence angles on solar panels.

• Spectral Losses: Reflect changes in the solar spectrum as light travels through the atmosphere.

• Conversion Losses: Arise during the conversion of sunlight into electrical energy within PV cells.

• DC Losses: This happens due to resistance in cables before inverter conversion.

• Inverter (Power Limitation) Losses: Occur when generated power exceeds inverter capacity.

• Inverter (DC/AC Conversion) Losses: Result from inefficiencies during DC to AC conversion.

• Auxiliary Losses: Come from self-consumption by auxiliary equipment.

• AC Cable Losses (LV): Occur due to resistance in low-voltage cables as current flows from the inverter.

• TR Losses (LV/MV): Losses caused by transformation from low to medium voltages.

• AC Cable Losses (MV): Occur in medium-voltage cables during longer distance transmission.

• TR Losses (MV/HV): Losses caused by transformation from medium to high voltages (if power transformer is used).

• AC Cable Losses (HV): Occur in high-voltage cables connecting the power transformer (if used) to the grid.

• Internal Unavailability Losses: Caused by maintenance or failures of internal components.

• External Unavailability Losses: These are caused by external factors like grid outages or regulatory shutdowns.

More details on losses and how they are calculated are described in the Solargis Evaluate simulation chain document.