What can PVSyst do? 9 beginner-friendly features

Table of Contents

• What is PVSyst

• Function 1 Preliminary estimate in early-stage planning

• Function 2 Organization of site and meteorological data

• Function 3 Definition of installation surface conditions

• Function 4 Verification of system configuration and capacity design

• Function 5 Hourly power generation simulation

• Function 6 Verification of array loss breakdown

• Function 7 Evaluation of linear shading losses and electrical losses

• Function 8 Comparison of alternatives and economic evaluation

• Function 9 Comparison with measured data and anomaly detection

• What beginners should know before introduction

• Summary

What is PVSyst?

PVSyst is dedicated software for studying photovoltaic systems, sizing capacity, evaluating performance, and analyzing data. In the official documentation it is presented as an environment that covers not only grid-connected systems but also stand-alone systems, pumping applications, and DC-system applications, and it is designed so that a meteorological database, component database, various tools, and measured-data analysis can be handled within a single integrated framework. In other words, it is easier to understand PVSyst not as a calculator that simply produces a one-time annual energy estimate, but as practical software for linking design, generation forecasting, and verification while organizing and consolidating a project's assumptions.

What beginners should know first is that this software is not a tool that simply returns a single number. The official help explains that, within a framework called a project, it holds geographic conditions and time-based weather data, and that it is structured to allow comparison of multiple simulation scenarios; it also shows that results include many variables that can be displayed by month, day, and hour. In other words, PVSyst is software that makes it easy to see not only the energy production figure but also the reasons behind that number, its weaknesses, and how it differs from alternative options. When practitioners search for "What is PVSyst," what they really want to know is precisely this overall picture.

Another feature of PVSyst is that it is easy to use flexibly according to the progress of a project. In the initial stage you can quickly produce monthly estimates with few input conditions, and in the full-scale stage you tighten up shading and losses using hour-by-hour simulations—this two-stage approach is officially organized. Rather than relying on perfect design values from the start, it matches the practical workflow of beginning with rough proposals and gradually increasing accuracy, making it easy to become familiar with for both first-time users and those who use it professionally.

Feature 1 Preliminary Estimation in the Early Planning Stage

One of the first useful features in PVSyst is the preliminary estimate for the early planning stage. According to the official description regarding pre-design, this is intended to quickly perform a monthly-based power generation assessment using only a few general conditions, and is considered suitable for site evaluation and initial system sizing studies. Even at a stage where specific components have not yet been decided in detail, it is easy to produce a rough outlook from location, orientation, and approximate capacity conditions, making it useful for screening candidate sites and confirming the overall direction.

In practice, it is rare for equipment models, row layouts, and shading conditions to be decided from the outset. There may be candidate sites, but the final layout is undecided; the capacity is visible, but the configuration is still to be determined — projects often start in that state. Proceeding with a mindset intended only for detailed design at that stage makes data entry heavy and actually slows the pace of evaluation. PVSyst’s preliminary design is suited to grasping the overall picture with limited information, making it useful for internal initial decisions and for organizing things before making a proposal. For beginners, it’s easiest to think of it as a feature to roughly see how much can be achieved at the start.

However, what is important when using this feature is not to treat the numbers produced here as finalized values for detailed design. The official guidance also indicates that preliminary design is intended for rough estimates and should not be used for detailed system design. What makes PVSyst useful is not so much that it can produce rough estimates, but that it allows you to connect the same workflow from rough estimates to detailed design. Create an initial proposal quickly and then increase the accuracy afterward. This is where the true value of this feature lies.

Feature 2 Organization of Sites and Weather Data

The second function is organizing sites and meteorological data. The official help lists the roles of the meteorological database as creating geographic sites, generating hourly meteorological data, visualizing meteorological data, comparing data sources, and importing external files. In other words, PVSyst is not software that starts by selecting equipment, but software that starts by deciding “which location” and “which meteorological assumptions” to look at. Because the results of solar power generation strongly depend on site conditions, being able to clarify this entry point is a very significant feature.

What beginners often overlook here is assuming meteorological data to be a single fixed value. In reality, how results appear can change depending on which data source you use, how you consider the target year and averaging period, and how you assess the reliability of temperature data. Even official comparisons of data sources explain that there are differences in analysis methods, available parameters, and the impacts of climate change, and that the differences between sources are not insignificant. PVSyst's strength is that it treats those differences not as invisible issues to be ignored, but as elements that can be compared and chosen.

Furthermore, PVSyst also provides a workflow for importing measured data and custom data. The official measured-data feature is said to allow importing data from almost any text CSV format as hourly or higher time-resolution data and viewing it in tables and graphs. In other words, there is an entry point not only to view existing reference datasets but also to incorporate the information you have into design and validation. The ease of linking meteorological and measured data is a major advantage for bringing desk-based design closer to on-site realities.

Function 3 Definition of installation surface conditions

The third feature is the definition of installation surface conditions. In PVSyst project design, you can define the orientation and tilt of the installation surface, and, if necessary, whether tracking is used and the row arrangement. This is because, even with the same site’s meteorological conditions, the amount and timing of actual received sunlight change depending on which direction it faces and at what angle it is placed. In solar power generation, not only “which region” but also “how the surface is placed in that region” affects the results. This software allows those installation surface conditions to be clearly set as an initial element of the design.

This feature is useful in practice because it makes it easy to compare proposals with different orientations and tilts. It becomes easier to organize alternatives—south-facing, east–west-facing, shallow tilt, steep tilt—within the same project context. In formal project design, the results also include variables related to geometric conditions, so it is easy to preserve as assumptions not only the differences in energy yield but the differences in installation conditions themselves. For beginners, it’s easy to think “can simply changing the angle really make that much difference?”, but PVSyst makes those changes visible as numbers.

Also, the mounting surface conditions influence how you interpret the losses and shading examined later. If orientation and tilt remain ambiguous, it becomes difficult to read how shadows fall, the seasonal variations, and the meaning of performance ratios. What beginners should grasp first is that the mounting surface conditions are not merely input fields but the foundation that determines all subsequent results. Being able to properly establish this foundation is one of PVSyst’s core functions.

Function 4 System Configuration and Capacity Design Verification

The fourth function is the verification of system configuration and capacity design. In the official grid-connected system definition, the system is explained as being composed of photovoltaic modules, strings, conversion equipment, and the connection to the grid. In PVSyst, after deciding the installation surface, you can design which components to use, how many in series and in parallel to assemble, and which inputs to assign them to. This means you can check not only "how many kilowatts to install" but also "how that capacity will be realized."

This feature is important because even with the same nominal output, the system's behavior changes depending on how it is configured. Not only the orientation and tilt, but also the number of series and parallel strings and the compatibility with the operating range of the conversion equipment can greatly affect the results. PVSyst makes it easy to check whether a proposal that looks good based only on capacity is actually feasible as a real configuration, so it helps reduce design oversights. Beginners in particular tend to focus on the generation numbers, but in practice “whether that configuration can actually be built” is just as important.

Furthermore, PVSyst includes a component database. According to the official documentation, it covers modules, converters for grid connection, batteries, pumps, manufacturer information, and user-defined pricing. This makes it easier to create a baseline configuration and to organize the configuration differences between alternative proposals. Of course, as the official documentation also notes, database values are not guaranteed and must be checked against the latest specifications, but in terms of speed when getting started and ease of organizing configurations, it is a very practical feature.

Feature 5 Hourly Power Generation Simulation

The fifth feature is time-step power generation simulation. In PVSyst’s official overview, project design is described as being carried out through detailed time-step simulations for design and performance analysis. Furthermore, it indicates that simulation variables such as weather, incident irradiance, array behavior, conversion equipment behavior, and energy output can be output on a time-step basis. In other words, a characteristic of this software is that you can see not only annual totals but also how things change throughout the day and across seasons.

This feature is useful in practice because it makes it easier to find quirks that aren’t visible from total figures alone. For example, even if the annual energy production looks reasonably good, output may drop significantly in summer due to temperature, or shading may have a strong effect only in the mornings and evenings. Alternatively, constraints on the conversion side may be noticeable only during certain time periods. PVSyst makes it easy to follow these temporal changes, making it much easier to understand deeply “why that result occurred.” This perspective is far more likely to lead to design improvements than looking only at the total generation.

Also, the value of time-based (hourly) simulation is that it makes differences between design proposals easier to read in detail. Even if annual values are similar, monthly or hourly results can differ significantly. Beginners tend to judge performance based only on the annual energy production figures, but PVSyst goes a step further by providing functions to check "which time periods are being captured and to what extent" and "which seasons it is weak in." This is a great help in improving the accuracy of designs.

Feature 6: View Breakdown of Array Losses

The sixth feature is checking the breakdown of array losses. In the official description of array losses, factors that reduce array output relative to nominal output under STC conditions are organized as "array losses," and these are said to be consistent with the concepts of performance ratio and normalized performance indicators. In PVSyst, because losses such as low irradiance, temperature, quality differences, mismatch, and wiring can be handled separately, the fact that "the result is low" can be decomposed and inspected as its constituent breakdown.

What beginners particularly tend to overlook are low irradiance and temperature. Under low irradiance, generation does not scale proportionally; losses occur because module efficiency drops, and when temperature is high, output decreases. On top of this, wiring losses, variations between modules, and mismatches compound. PVSyst allows you to check these separately rather than only as a total, making it easier to identify which is the primary cause. A major advantage is that when improving a design, it becomes easier to find what to tackle first.

Also, the official explanation of the loss diagram states that many of these losses are visualized in the loss diagram as reductions in energy. In other words, PVSyst makes it easy to see both the numbers for individual losses and the overall flow. Beginners tend to think of losses as a single safety factor, but in reality many small losses add up. Being able to understand that structure is a major value of this feature.

Feature 7 Evaluation of Linear Shadow Losses and Electrical Losses

The seventh feature is the evaluation of linear shading losses and electrical shading losses. In the official shading-related documentation, linear shading loss is treated as a simple reduction due to reduced irradiance, whereas electrical shading loss is defined as an additional loss that occurs beyond that. Furthermore, when part of a cell or module is shaded, the I/V characteristics are disturbed and the string current is limited by the most disadvantaged cell, causing losses beyond the linear shortfall. In other words, PVSyst does not treat shading as merely a "fraction of darkened area" but is software that can evaluate the electrical effects as well.

The practical value of this feature is very high. Even when a shadow appears to affect only a small area, the behavior of an entire string can be disrupted, and power generation can drop more than expected. The official Module Layout feature is capable of calculating electrical shading mismatch losses by defining the position and interconnection of each module in detail. An approximate partition model suited to regular matrix arrangements is also provided. In other words, shadow assessments can be performed in greater or lesser depth depending on the complexity of the project.

For beginners, this may be the point where they feel, "Why is PVSyst more difficult than a simple power-generation calculation?" Conversely, the more a project requires careful assessment of shading, the greater the value of this software. The ability to check not only the visible shading but also its electrical effects is one of the main reasons this software is supported in the solar industry. Avoiding underestimation of shading so as not to make design mistakes is extremely important in practice.

Function 8: Comparison of Alternatives and Economic Evaluation

The eighth feature is comparison of alternatives and economic evaluation. According to PVSyst’s official description, you can have multiple system variants within a project and compare each of them. Because you can keep alternatives for different orientations, different tilt angles, different loss-condition settings, and different shading conditions, it is easy to organize “what changed and how it changed.” In design practice, it is rare to see a single correct answer from the outset, so this comparison function is extremely practical.

PVSyst also officially states that it has an economic evaluation function that allows users to set initial installation costs, annual expenses, financing conditions, tariff/pricing conditions, and so on, in order to estimate generation costs and long-term profitability. This function acknowledges that a proposal with higher energy production is not necessarily the optimal one. If the configuration is made more complex to gain a small increase in production, the project as a whole can become unprofitable. Because PVSyst makes it easy to review technical option comparisons and their business outlook in a single workflow, it helps bridge design and decision-making.

Beginners may think, "Is an economic evaluation really necessary?", but in practice the merits of a design ultimately tie into its economics. This software makes it easier for the design team to explain the numbers by allowing them to check not only the amount of power generated but also how that generation looks as a business. It may appear to be a somewhat later-stage feature, but it is extremely important in practice.

Function 9 Measured Data Comparison and Anomaly Detection

The ninth feature is measured-data comparison and anomaly detection. The official description of measured-data analysis states that its purpose is to closely compare on-site measured data with simulation values on an hourly or daily basis, and that it also makes it easy to detect even small anomalies in systems that are actually in operation. In other words, this software can be used not only for pre-design predictions but also for post-operation verification. This is a major reason why its value increases the longer it is used.

Comparing measured data is important because you can learn from the differences between predictions and actual results. Differences themselves are not uncommon, but whether you can tell if they stem from different weather conditions, lenient loss settings, or equipment-side malfunctions will affect the accuracy of your next project. On the official measured data file check page, there are monthly, daily, and hourly tables and graphs and a synchronization check function that allow you to check the quality of the data itself. In other words, PVSyst is not just a tool for producing forecasts and leaving them as-is; it is also an environment for refining those forecasts through verification.

For designers, a major advantage is being able to review the assumptions made during design and the actual operational performance in the same workflow. If a discrepancy between predicted and actual performance becomes apparent at a site, they can revise loss assumptions and the way shading conditions are set for the next project. PVSyst is not merely power-generation simulation software; it also serves as a learning tool for progressively improving design quality. Beginners don't need to use it to that extent at first, but simply knowing that it can be used that way in the future will significantly change how they perceive the software.

What beginners should know before getting started

Summarizing the nine functions so far should make it clear that this software is quite multifunctional. However, there are some things beginners should keep in mind before getting started. First, don’t try to master everything at once. The official tutorial also shows a workflow of creating a baseline plan with minimal conditions at first, and then gradually adding losses and shadows. In other words, this software is easier to understand naturally by starting from a baseline and gradually increasing the check items, rather than trying to use all functions perfectly from the beginning.

Second, do not treat databases and default values as absolute. The official guidance explains that while component databases are convenient, they need to be checked against the latest specifications, and comparisons of weather data also show differences and uncertainties between sources. In other words, having powerful features does not automatically make the tool reliable. The more carefully you handle the assumptions, the greater the value of this software. Beginners should adopt the mindset of not “receiving an answer,” but “working toward the answer while clarifying the conditions.”

Third, that desk-based design accuracy and the accuracy of on-site information are a package. If you delve into detailed shadow analysis and comparisons with actual measurements, the positional relationships and the quality of measurement data become crucial. No matter how finely you examine things inside the software, if on-site positioning and obstacle identification are vague, discrepancies between design assumptions and reality will remain. In other words, this software is not a self-contained magic box but a practical tool that becomes effective when combined with on-site information. Understanding this from the start makes it less likely that expectations will shift after deployment.

Summary

When explaining what PVSyst can do for beginners, nine functions are particularly important: preliminary estimates in the early planning stage, organization of site and meteorological data, definition of installation surface conditions, verification of system configuration and sizing, time-step generation simulation, breakdown of array losses, evaluation of linear shading losses and electrical losses, comparison of alternatives and economic assessment, and comparison with measured data for anomaly detection. In other words, this software is not just for looking at the annual energy production number; it is an integrated tool for confirming the connection between design conditions and results.

What really matters for practitioners is not to use PVSyst as a black box. The more you verify which location, which meteorological conditions, which orientation, which configuration, and which losses you assume — and consequently where the energy was reduced — the more valuable the software becomes. If you use it not as a tool to produce numbers but as a tool to give those numbers a rationale, the quality of design and explanation will be greatly improved.

And the more thoroughly you verify meteorology, the mounting surface, losses, shading, and comparisons at the desktop, the more important the accuracy of on-site positional information and equipment layout becomes. Even if you refine design conditions in PVSyst in detail, if on-site staking and obstacle identification are ambiguous, discrepancies between design assumptions and construction realities tend to grow. That is precisely why, in the design phase you should organize desktop conditions in PVSyst, and in the field phase combine that with an iPhone-mounted, high-precision GNSS positioning device like LRTK — this makes it easier to link design, construction, and operations and maintenance more consistently. The more items you check in PVSyst, the better the compatibility with field measures that support positioning accuracy, such as LRTK.