--- title: "PVOUT and performance ratio (PR)" slug: "energy-system-statistics-losses-and-long-term-degradation" description: "Explore PV energy systems statistics, losses, and long-term degradation data to optimize performance and enhance decision-making for your solar projects." updated: 2026-09-25T06:28:56Z published: 2026-09-25T06:28:56Z canonical: "kb.solargis.com/energy-system-statistics-losses-and-long-term-degradation" --- > ## Documentation Index > Fetch the complete documentation index at: https://kb.solargis.com/llms.txt > Use this file to discover all available pages before exploring further. # PVOUT and performance ratio (PR) **In this document** You'll learn how to read the PVOUT charts in the project's Analysis section: the PVOUT specific and performance ratio (PR) chart, the monthly statistics chart for PVOUT total, the yearly Time Series, and the monthly statistics table, together with the unavailability and snow loss toggle applied across them and the tabs offering PVOUT at shorter time steps. The **PVOUT charts** present the simulated energy output of your PV energy system across the whole time series. They are available in the project's Analysis section under **PV statistics**, on the **PVOUT specific and PR** and **PVOUT total** pages. **PVOUT specific** is normalised to the installed capacity. It describes the potential of your site and technology and serves as a reference for comparisons. **PVOUT total** is the absolute output of the whole system, reflecting the actual modules and inverters used in the project. For the other chart groups and an introduction to the Analysis section, see [How to read the charts](/v1/docs/how-to-read-the-charts). For the lifetime production estimates, see [PV long-term degradation](/v1/docs/pv-long-term-degradation), and for the stage-by-stage loss breakdown, see [PV system losses](/v1/docs/pv-system-losses). For inverter statistics chart and explanation, see [Inverter statistics](/v1/docs/inverter-statistics). > [!WARNING] > **Important**: These pages are available for **PV energy systems only**. They are not provided for GTI energy systems. The values shown are **theoretical PVOUT** — they do not take degradation losses into account. > [!TIP] > **Notes**: > > - 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 the data from January of the same year. > - Use the **unavailability toggle** in the top right corner to include or exclude internal and external unavailability and snow loss values in the charts and tables. They are included by default. You can configure both losses in the [Energy system designer](https://kb.solargis.com/docs/cabling-and-system-losses#system-losses). ## PVOUT specific and performance ratio This chart combines two parameters. The bars represent the **monthly average** specific PVOUT calculated from all years in the time series, and the whiskers show the **minimum** and **maximum** monthly values reached throughout the time series. The **performance ratio (PR)** line is plotted against the secondary axis on the right. It expresses how much of the irradiation reaching the modules the system delivers as usable electricity in the given month. ![](https://cdn.document360.io/ae2d502f-6c0d-4865-a68e-43ad8da61149/Images/Documentation/image-D3BIE43K.png?sv=2026-02-06&spr=https&st=2026-11-02T00%3A20%3A11Z&se=2026-11-02T01%3A20%3A11Z&sr=c&sp=r&sig=CRRCawV5EliArck3rn%2FoUO%2BdhQFXl1nkrEkpIK1NmqU%3D) | | **Unit** | | --- | --- | | **X-axis** | Month | | **Y-axis (left)** | PVOUT specific [kWh/kWp] | | **Y-axis (right)** | Performance ratio [%] | ### How to use it This chart lets you **compare seasonal production** and spot the months in which the system operates least efficiently. Production and efficiency do not necessarily peak together: in the warmest months, output is at its highest while the performance ratio typically drops because of higher module temperatures. The distance between the minimum and maximum values shows how much a given month can deviate from year to year, which is useful when judging how reliable the monthly production estimate is. ## Yearly Time Series This chart plots the **yearly PVOUT** for every complete year in the time series, together with the **average** over the whole series and the **standard deviation** band around it. The average serves as a central reference point, and the standard deviation band shows the average deviation from it, providing insight into the consistency of production over the time series. ![](https://cdn.document360.io/ae2d502f-6c0d-4865-a68e-43ad8da61149/Images/Documentation/image-PT9F0JMY.png?sv=2026-02-06&spr=https&st=2026-11-02T00%3A20%3A11Z&se=2026-11-02T01%3A20%3A11Z&sr=c&sp=r&sig=CRRCawV5EliArck3rn%2FoUO%2BdhQFXl1nkrEkpIK1NmqU%3D) | | **Unit** | | --- | --- | | **X-axis** | Year | | **Y-axis** | PVOUT specific [kWh/kWp] or PVOUT total [MWh] | ### How to use it This chart shows the **interannual variability** **of energy production**: how far a single year can deviate from the long-term average, and whether the site delivers stable yields or alternates between strong and weak years. Use it to identify exceptionally high or low production years worth investigating, and to judge the risk margin to apply when preparing yield and financial estimates. ## Monthly statistics table Below the charts, the **Monthly statistics** table lists the exact values behind them: the long-term **average** for each month, the **yearly share** of each month in percent, and the **minimum** and **maximum** monthly values. The last column summarises the whole year. ![](https://cdn.document360.io/ae2d502f-6c0d-4865-a68e-43ad8da61149/Images/Documentation/image-GGEBHYOO.png?sv=2026-02-06&spr=https&st=2026-11-02T00%3A20%3A11Z&se=2026-11-02T01%3A20%3A11Z&sr=c&sp=r&sig=CRRCawV5EliArck3rn%2FoUO%2BdhQFXl1nkrEkpIK1NmqU%3D) ### How to use it Use the table when you need **precise numbers** rather than a visual comparison — for example, to check how much each month contributes to the annual yield, or to transfer the values into your own production and financial models. ## PVOUT at shorter time steps The charts described above are shown on the **Yearly–monthly** tab. Depending on the granularity of the simulation (the selected dataset), the **Daily**, **Hourly**, and **15-minute** tabs present PVOUT values at shorter time steps. These charts follow the same logic as for the other parameters. Read the details in [Daily charts](/v1/docs/daily-charts), [Hourly charts](/v1/docs/hourly-charts), and [15-minute values charts](/v1/docs/15-minute-values-charts). > **Tips**: > > - Hover over any chart to view the values for a particular month or year. > - If you want the charts and tables to account for **unavailability and snow losses**, activate the toggle in the top right corner.