10 Practical Operations to Learn from the PVSyst Manual

Table of Contents

• Key Concepts to Grasp Before Reading the PVSyst Manual for Practical Work

• Operation 1: Organize the project requirements as a project

• Step 2: Verify meteorological data and site conditions

• Operation 3: Adjust the azimuth and tilt angles to match the actual project

• Operation 4: Configure the modules and power conditioner

• Operation 5: Verify the string configuration and capacity ratio

• Operation 6: Handling distant shadows and horizon conditions

• Operation 7: Check proximity shadows in a 3D scene

• Step 8: Enter the loss conditions to reflect the actual situation

• Operation 9: Reading the simulation results and loss plots

• Operation 10: Compare multiple proposals and summarize them in a report

• Tips for continuing to use the PVSyst manual in practical work

Key concepts to grasp before reading the PVSyst manual for practical use

It's not uncommon for people to open the PVSyst manual and feel unsure where to start in order to make it useful for practical work. In PV system design and energy yield simulation, many conditions are interlinked: location, meteorological data, azimuth, tilt, equipment configuration, shading, losses, and report verification. Therefore, rather than reading the manual from start to finish, it is more efficient to understand it on an operation-by-operation basis according to what you want to check in practice.

PVSyst is PC software used for the design, sizing studies, and data analysis of photovoltaic power generation systems, and it is configured to handle systems such as grid-connected, stand-alone, pumping systems, and DC grid. It also includes meteorological data, an equipment database, and various analysis tools. The official documentation explains that project design is a process for performing detailed simulations, that a project incorporates geographic conditions and meteorological data, and that multiple simulation scenarios are managed as variants.

What’s important in practice is to use the PVSyst manual not as a “screen guide” but as a “checklist to sequentially firm up design conditions.” For example, if the energy production is lower than expected, simply rerunning the simulation will not reveal the cause. You need to check, in order, whether the meteorological data are appropriate, whether the orientation and tilt match the site conditions, whether the equipment selection is reasonable, whether shading is being over- or under-estimated, and whether the loss inputs are realistic.

This article organizes into ten operations in the PVSyst manual that practitioners should particularly remember. It explains a workflow that can be used for project work, covering not only the screens where beginners tend to get confused at first, but also design comparison, shading analysis, how to read loss diagrams, and report review.

Step 1: Organize the project requirements into a project

The first operation you should learn is to organize the project conditions as a project. In PVSyst, rather than calculating energy production immediately, you first create a project and enter the site, meteorological data, system proposal, and design conditions into it. If you proceed with these unclear, when you look at the results later you will not know under what conditions the calculations were performed.

In practice, the way you name projects is surprisingly important. Including the project title, location, facility size, study/design phase, creation date, and so on makes it less likely you'll become confused when comparing multiple options later. This is especially true for projects where initial proposals, schematic designs, detailed designs, and revised versions are mixed, since conditions can change slightly even for the same site. If project names or variant names are ambiguous, you will be unable to determine which results to use during internal reviews or when explaining them to the client.

The PVSyst manual outlines the project design workflow: first define the project, then for each variant set the orientation, system, and detailed conditions, verify parameter consistency, and finally proceed to the simulation. Red warnings indicate problems that will prevent the simulation, while orange warnings are treated as conditions that require attention.

In practice, it is important not to be satisfied with simply clearing the red warnings. There are cases where calculations can proceed even with orange warnings, but whether that is acceptable under the project conditions is another matter. For example, a simulation may run even if the equipment configuration’s voltage range is near its boundary, input conditions remain at their default values, or shading and loss conditions have not been adjusted. However, submitting the report as-is may leave you with difficulty explaining it later.

Immediately after creating a project, first clarify "what this file is intended to examine." Whether it is for a rough estimate, for design comparison, for verifying estimated energy production for a financial institution, or for internal review, the required input accuracy and the items to check will differ. Because the PVSyst manual is feature-rich, you do not need to read every item to the same depth. Deciding, according to the objective, which conditions should be examined precisely is the first step in practical work.

Operation 2: Check meteorological data and site conditions

The next important step is to verify the meteorological data and site conditions. In photovoltaic simulations, meteorological conditions such as solar irradiance, air temperature, and wind speed greatly affect power output. When reading the PVSyst manual, the explanations of how to import meteorological data and how to configure the site should be regarded not as mere initial setup but as critical items that determine the reliability of the results.

For site conditions, confirm latitude, longitude, elevation, time zone, and the surrounding environment. If the entered location is significantly off, it will affect calculations of solar elevation and solar radiation conditions. In particular, even within the same prefecture, coastal areas, mountainous areas, basins, and snow-prone regions can have different meteorological conditions. In practice, it is important not only to select meteorological data close to the site but also to verify whether that data can withstand scrutiny in the project's documentation.

When examining meteorological data, avoid judging based solely on annual solar radiation. Also check monthly trends, the difference between summer and winter, the distribution of temperatures, and the presence of missing or anomalous values. Even if the annual value alone appears reasonable, if a particular month's value is unnatural, the seasonal variation in power generation may not reflect reality. For rooftop installations, self-consumption systems, battery-coupled setups, and snowy regions, monthly generation patterns directly affect economics and operational planning.

On PVSyst's results screen, numerous variables related to meteorological data and irradiance that are calculated during the simulation are available. The official documentation indicates that variables such as horizontal plane global irradiance, horizontal plane diffuse irradiance, horizontal plane direct irradiance, ambient temperature, wind speed, irradiance incident on the tilted surface, and effective irradiance accounting for shading, IAM, and soiling are treated as result variables.

A common mistake in practice is to end the check after merely selecting the meteorological data. When reading the meteorological-data sections of the PVSyst manual, you need to be aware not only of the import procedures but also of how to validate that data. Comparing it with past performance, nearby stations, and alternative data sources will increase the explanatory power of the simulation results.

Also, while simplified data may be sufficient at the initial proposal stage, when approaching stages that involve investment decisions or contracts you should clearly document the source of the meteorological data and the reasons for adopting it. PVSyst can model detailed loss settings and shading analysis, but if the underlying meteorological conditions are inappropriate, the value of those detailed settings is diminished. Carefully verifying the initial site conditions and meteorological data is the foundation for high-accuracy simulations.

Operation 3: Match the Azimuth and Tilt Angles to the Actual Project

The third operation is the setting of the azimuth and tilt angles. When using the PVSyst manual in practice, you must read this section while cross-checking it against your project drawings and on-site conditions. The orientation and angle of the solar panels affect not only the power generation but also seasonal generation patterns, shading exposure, racking plans, and roof integration.

For ground-mounted installations, it is common to consider conditions close to due south orientation and optimal tilt, but in reality there are constraints such as land shape, site development plans, drainage, neighboring property boundaries, roads, and maintenance access routes. For rooftop installations, you need to match the orientation and slope of the roof surface, so you often cannot freely choose the ideal angle. Therefore, when inputting azimuth and tilt angles in PVSyst, it is important to reflect the layout that will actually be constructed rather than the ideal design values.

When entering the azimuth, always confirm which direction is being used as the reference. If north on the drawing, true north, magnetic north, the building axis, and the CAD coordinate orientation are mixed, discrepancies of several to a dozen degrees can occur. For tilt angles, avoid confusing roof pitch, mounting angle, and panel surface angle. In particular for trapezoidal-sheet metal roofs, pitched roofs, east-west installations, and low-angle installations, you must carefully match the notation on the drawings with the input values in PVSyst.

In PVSyst, you define the plane orientation for each variant within a project, and then set the system conditions. In other words, azimuth and tilt are not mere drawing information but the assumptions for each simulation scenario. When comparing multiple scenarios, managing separate variants that change only orientation or tilt, variants that change only equipment configuration, and variants that change loss conditions makes it easier to read the differences in the results.

A practical approach in the field is not to treat azimuth and tilt angles as "enter once and forget." Compare them with the site layout, roof plan, racking drawings, site photographs, and survey data, and if there are changes, immediately reflect them in the PVSyst variant. As the design progresses, aisle widths, spacings, number of panel tiers, rooftop obstructions, and maintenance spaces may change. When these change, the effective installation area and shading conditions also change, affecting the final energy yield.

Operation 4: Configure the modules and power conditioner

The fourth is the module and power conditioner settings. When reading equipment settings in the PVSyst manual, you need not only to select equipment from the database but also to check that the chosen equipment matches the project's conditions. The module's nominal power output, temperature characteristics, size, electrical characteristics, and the power conditioner's input voltage range, maximum input current, number of MPPTs, conversion efficiency, and so on, affect the overall feasibility of the system.

A common stumbling block for beginners is selecting equipment based only on the capacity shown in the catalog. For example, even with the same system capacity, the voltage and current conditions change depending on the number of modules, the number of series strings, the number of parallel strings, and the number of power conditioners. You must check whether the open-circuit voltage at low temperature will exceed the upper limit, whether the operating voltage at high temperature falls within the MPPT range, and whether the input current stays within the allowable range.

PVSyst helps configure PV arrays based on the selected equipment, but the final design decisions must be made by the user. The PVSyst manual describes an approach to project design that involves selecting specific system components and advancing the PV array design, such as the number of modules in series and the number of parallel strings.

In practice, attention must be paid to avoiding mix-ups of manufacturer model numbers. Even within the same series there can be different power outputs, specification revisions, region-specific models, or successor models. Verify that the model registered in the PVSyst database exactly matches the model actually being used. If they do not match exactly, determine whether to use an approximate model, create user-defined data, and how to explain this in the report.

Also, in the detailed design phase, confirm that the equipment settings in PVSyst match the single-line wiring diagram, string table, and equipment layout drawing. When the simulation team and the electrical design team are separate, something that is valid in PVSyst may not align with the actual panel configurations, junction boxes, cable routes, and construction conditions. The equipment-setting items in the PVSyst manual should be used not merely as software operations but as means to verify consistency with the design documents.

Operation 5: Check the string configuration and capacity ratio

The fifth is checking the string configuration and capacity ratio. When you set up the system in PVSyst, you can verify the balance between the DC side and the AC side from the number of modules, the number in series, the number in parallel, and the power conditioner capacity. This is very important in practice because it affects power generation, clipping, equipment protection, and constructability.

In string configuration, first check whether the number of modules in series is appropriate for the temperature conditions. Module voltage increases in cold conditions and decreases at high temperatures. If the number of modules in series is too high, it may exceed the maximum voltage limit at low temperatures, and if it is too low, it may fall outside the MPPT range at high temperatures. Even if PVSyst does not issue a warning, it is important to cross-check with the design criteria and equipment specifications.

When looking at capacity ratios, you should avoid the simple assumption that increasing DC capacity will always increase annual power generation. Increasing DC capacity can cause the power conditioner to hit its output limit during periods of strong insolation, making output curtailment and clipping more likely. Conversely, excessively increasing AC capacity can be disadvantageous in terms of equipment costs and efficiency. You need to make judgments that take into account the project's feed-in conditions, self-consumption conditions, installation constraints, and costs.

When reading the PVSyst manual, it is also important to understand the meaning of warning messages. Red warnings indicate issues that should be resolved before running calculations, while orange warnings are conditions that may allow calculations but require caution. In particular, warnings related to voltage range, overloading, equipment combinations, and unset items should be reviewed before submitting the report.

In practice, multiple variants with different string configurations are created to compare energy production, losses, equipment count, and constructability. In such cases, saving the variants separately within a single project makes later comparison easier. For example, creating variants that keep the same panel layout but only change the power conditioner capacity, that change the number of modules in series, or that separate the layout into east-west arrays makes it easier to explain the impact of capacity ratios.

String configurations may appear as numerical combinations in PVSyst, but on-site they are directly tied to the number of cables, junction box locations, ease of inspection, and construction procedures. The optimal proposal in simulation is not necessarily the optimal one for construction. For practical operations, it is important to make a comprehensive judgment that includes not only power generation but also design, construction, and maintenance.

Operation 6: Handling Distant Shadows and Horizon Conditions

The sixth is the handling of distant shadows and horizon conditions. Obstructions far from the power plant—such as mountains, hills, clusters of buildings, forests, and variations in terrain elevation—affect power generation as horizon conditions. In particular, for projects in mountainous areas, basins, or sites with high surrounding terrain, direct solar radiation can be blocked in the mornings and evenings and in winter, causing differences in power generation.

The PVSyst manual presents the concept of treating distant shading as a horizon profile, represented by a series of points of elevation and azimuth angles. The official documentation explains that horizon profiles can be obtained from on-site measurements, maps, panoramic photographs, fisheye photographs, etc. It also states that horizon profiles whose elevations are all below 2 degrees are considered insignificant and will not be reflected in simulations or reports.

In practice, deciding whether to include distant shading is important. On flat terrain with no high surrounding topography, the influence of horizon conditions can be small. Conversely, in areas surrounded by mountains or where there is high terrain in the east-west direction, it can have a large impact on morning and evening power output. Especially during winter, when the solar altitude is low, the effect of distant shading tends to become more noticeable.

When configuring distant shadows, be careful not to confuse them with near shadows. Distant shadows deal with whether the sun is hidden below the horizon and are considered a condition that uniformly affects the entire power plant. If nearby buildings, adjacent panel rows, rooftop equipment, trees, etc., partially cast shadows on panels, they need to be treated separately as near shadows.

When reading the PVSyst manual, you should consider not only how to input distant shading but also the accuracy of the horizon data you obtain. Reliability varies depending on whether the data were measured on site, estimated from maps, or created from photographs. For important projects, documenting the reasons for adopting the horizon conditions in reports or internal materials will make it easier to explain later.

Operation 7: Verify proximity shadows in a 3D scene

The seventh is the operation of checking near shadows in the 3D scene. In the PVSyst manual, shadow analysis is a particularly tricky area. The official documentation also explains that shadow settings are the most difficult part within PVSyst, and that during simulations shadow calculations are performed at each time step and different treatments are required for the direct, diffuse, and albedo components.

Objects considered in near-field shading include nearby buildings, trees, fences, rooftop penthouses, outdoor air-conditioning units, parapets, and adjacent panel rows. For ground-mounted installations, shadows from the rows in front and behind can be an issue; for roof-mounted installations, rooftop obstacles and level differences (steps) matter; for agrivoltaic systems, support posts and mounting structures can cause shading; and for systems co-located with battery storage, shadows from cubicles and containers may be problematic.

In PVSyst’s 3D scene, panel surfaces and obstructions are modeled to assess the impact of shading. However, in practice, “creating shapes” itself is not the objective. What matters is accurately representing the obstructions that affect energy production. Overly detailed models increase modeling time and computational workload. Conversely, omitting major obstructions can lead to underestimation of shading losses.

In large-scale projects, rather than modeling the entire site in detail, it is also necessary to adopt an approach that focuses on representative areas or those with the greatest impact. PVSyst’s official documentation states that for large projects, when shading calculations for the whole site are time-consuming or when you want to focus on a particular area, there is an option to perform shading calculations using only a subset of the PV tables in the 3D scene.

A key point to keep in mind in practical near-field shading work is to document the assumptions used in the modeling. If the basis for building heights, tree heights, parapet heights, row spacing, ground level, roof pitch, and similar parameters is unclear, it becomes difficult to explain shading losses. In particular, trees change shape with the seasons and as they grow, and building plans can change so that heights are altered by design revisions. Therefore, shading conditions are not something to set once and forget; they need to be reviewed whenever drawings or site conditions are updated.

Also, when reading the results of a shading analysis, check not only the annual losses but also which seasons and times of day are most affected. Whether shading occurs only in the winter mornings and evenings or whether it casts shade over daytime hours throughout the year will change design decisions. For self-consumption systems, it is also important to know whether the timing of shading coincides with demand peak periods.

Step 8: Enter loss conditions to match actual conditions

The eighth is the operation of entering loss conditions to match the actual situation. PVSyst can handle many loss factors such as temperature losses, wiring losses, soiling losses, IAM losses, mismatch, module quality, degradation, transformer losses, auxiliary consumption, and system downtime. Because these directly affect the energy production results, in practice you should always confirm whether it is acceptable to use the default values as-is.

In the official documentation, IAM, soiling, thermal, LID, module quality, mismatch, degradation, wiring, external transformers, auxiliary consumption, and system downtime are listed as array and system losses, and it explains that each loss can be checked in the simulation results on an hourly, daily, and monthly basis and is visualized in loss charts.

Soiling losses vary greatly depending on the region and installation conditions. In regions with heavy rainfall, high dust levels, frequent bird activity, sites near factories or roads, or on low‑slope roofs, the impact of soiling differs. The official PVSyst documentation explains that soiling losses are strongly dependent on rainfall, that monthly loss rates can be defined, and that if snow is a concern it can be treated as partial or complete soiling attenuation for specific months.

For temperature losses, the installation configuration is important. Ground-mounted, roof-mounted on a rack, flush to the roof, and building-integrated arrangements have different ventilation conditions on the module rear. The poorer the ventilation, the more the module temperature tends to rise, reducing power generation efficiency. When reading the temperature-related sections of the PVSyst manual, it is important not simply to enter coefficients, but to verify them against the actual on-site installation details.

When assessing wiring losses, confirm the cable lengths, currents, conductor cross-sectional areas, and routes on the DC and AC sides. In the preliminary stage, standard values may sometimes be used, but in the detailed design stage these must be aligned with the single-line wiring diagram and the cable plan. Especially in large-scale projects and projects with distributed layouts, cable lengths can end up longer than anticipated, increasing losses.

You also need to understand the meaning of the default values for IAM losses and module quality losses. PVSyst's IAM settings provide calculations and model selection based on module definitions, and using user-defined profiles requires careful handling. The official documentation also notes that manufacturers may overestimate IAM performance, so caution is advised when using user-defined profiles.

Loss conditions are not items to be used for conveniently adjusting the energy yield. It is important to enter values that can be explained based on site conditions, design conditions, maintenance plans, and equipment specifications. When using the PVSyst manual, proceeding while checking what each loss means, which conditions affect it, and where it appears in the results will increase the credibility of the simulation.

Operation 9: Reading Simulation Results and Loss Plots

The ninth skill is interpreting the simulation results and loss diagrams. When you run calculations in PVSyst, it outputs annual energy production, monthly energy production, performance ratio, various losses, reports, and so on. However, simply looking at the results screen and checking only the annual energy production is insufficient in practice. You need to determine which conditions are affecting the energy production and where there is room for improvement.

The PVSyst loss diagram is an important display for quickly understanding the quality of a PV system design and identifying the main loss factors. The official documentation states that the loss diagram is always included in the annual simulation report and can also be viewed on a monthly basis, and that loss rates are shown as a proportion of the upstream energy amounts and therefore cannot be simply added together.

In practice, when reviewing a loss diagram, you first check the largest losses. Whether shading losses, temperature losses, wiring losses, or inverter-related losses are dominant will determine the corrective measures. If shading losses are large, review the layout, inter-row spacing, obstructions, and horizon conditions. If temperature losses are large, check the mounting configuration and ventilation conditions. If wiring losses are large, consider cable routing, conductor cross-sectional area, and equipment placement.

It is also important to look at monthly results. Even if the annual power generation is the same, a plan that is strong in summer and one that is strong in winter will differ in self-consumption rate, feed-in revenue, and alignment with demand. In snowy regions the winter drop is important, and in hot regions temperature-related losses in summer can become large. For rooftop installations, shading at specific times of day can also affect monthly generation.

When reading the PVSyst manual, use it not only to check whether the numbers on the result screens are "correct", but also to explain "why those results occurred". For example, if the energy yield is low, sequentially isolate which of the meteorological data, azimuth, shading, losses, or system configuration is the primary cause. Conversely, if the energy yield is excessively high, exercise caution as well: check whether shading is being underestimated, whether soiling or downtime rates are set too low, or whether the meteorological data are overly optimistic.

When checking the results, we also examine the consistency of the report. We verify that the project name, site, equipment model, system capacity, azimuth, tilt, loss conditions, shading conditions, and monthly energy production do not contradict internal documents or drawings. PVSyst reports are convenient, but if there are input errors they will be reflected as is. Before submission, it is important to check not only the results but also the assumptions page.

Operation 10: Compare multiple proposals and compile them into a report

The tenth is the operation of comparing multiple scenarios and compiling them into a report. In practice, it is rare to finish after simulating only a single condition; multiple scenarios that vary panel layout, capacity, tilt angle, equipment configuration, shading conditions, and loss conditions are compared. In PVSyst, you can create variants within the same project and manage simulations with different conditions.

What’s important in a comparison is to make clear what was changed. If you change multiple conditions at the same time, it becomes difficult to tell what the differences in results are due to. For example, if Plan A changes both the number of panels and the power conditioner capacity, while Plan B also changes the shading conditions, it will be hard to explain the reasons for the differences in power generation. In practice, it is important to separate variants according to the purpose of the comparison.

The PVSyst manual recommends that, after the initial simulation, you review the results and then progressively add project-specific conditions, running a new simulation at each step to analyze the loss diagram. This makes it easier to understand the impact of each condition on the results.

When compiling a report, organize not only the annual energy production but also monthly energy production, the performance ratio, major losses, and assumptions. If it is for internal review, retain detailed differences in conditions; if it is for the owner, clearly present the key points necessary for decision-making. When financial institutions or third-party verification are involved, it is necessary to clarify the basis for meteorological data, shading conditions, loss assumptions, and equipment specifications.

When evaluating P50 and P90, a different perspective from that used for ordinary simulation results is required. The official documentation states that P50-P90 evaluation is a probabilistic approach for interpreting multi-year simulation results, that it is performed by entering additional parameters after the initial simulation, and that P50 corresponds to the simulation output in the initial state.

In practice, P50 and P90 are sometimes used for investment decisions and risk assessments, but correct values do not simply appear by pressing a button. It is important how you set the assumptions about uncertainties such as interannual variability of meteorological data, simulation uncertainties, equipment degradation, and downtime risks. When reading the PVSyst manual, you should understand the difference between a standard energy production report and a probabilistic assessment.

When preparing the report, present it in a way that can explain which option will ultimately be adopted. The option with the maximum power generation is not necessarily the optimal one. Judgments should take into account constructability, cost, maintainability, shading risk, room for future expansion, grid constraints, and self-consumption rate. PVSyst results are materials for decision-making, not the design decision itself. Mastering the manual means not only reading the results but being able to connect them to design decisions.

Tips for Continuing to Use the PVSyst Manual in Professional Practice

Although the operations you need to learn in the PVSyst manual may seem numerous, the workflow used in practice is relatively straightforward. First, organize the project conditions into a project, verify the meteorological data and site conditions, and adjust the azimuth and tilt to match the actual design. Then set up the equipment configuration, strings, shading, and losses, interpret the simulation results and loss diagrams, compare multiple scenarios, and compile them into a report.

The important thing is not to think of PVSyst simply as "software that outputs energy generation." In practice, it is a tool for verifying the validity of design conditions, breaking down the factors that affect energy generation, and creating materials that can be explained to stakeholders. Therefore, it is more useful to read the PVSyst manual as a practical verification procedure rather than merely as an operating guide.

Beginners can easily become confused if they try to learn all the features at once. Start by firmly grasping the basic workflow: project creation, meteorological data, orientation and tilt, equipment settings, simulation, loss diagram, and report review. After that, depending on the project, add items such as near-field and far-field shading, detailed losses, economic evaluation, and P50–P90 assessment to help solidify your understanding.

What matters for practitioners is the habit of recording the rationale behind input values. If you record why you used a particular meteorological data set, why you chose that loss rate, what basis you used to create the shading conditions, and which drawings the equipment configuration matches, it will be easier to respond to later changes or inquiries. A PVSyst report alone may not always convey the reasons for those decisions sufficiently.

Also, when design changes occur, be sure to review the conditions in PVSyst as well. Changes such as the number of panels changing, rooftop obstructions being added, the mounting angle changing, the model of the power conditioner changing, or the cable routing changing will affect energy generation and losses. Regularly checking that the design documents and the simulation conditions are not out of alignment improves the quality of work.

If you master the top 10 practical operations from the PVSyst manual, you will be able not only to operate the software but also to explain the basis for the estimated energy yield. In designing solar power systems, it is more important to explain under which conditions the figures are based, how reliable they are, and what risks they include, than simply producing numbers. To use PVSyst in practice, the most reliable way to learn is to repeatedly organize project-specific conditions, verify inputs, analyze results, and conduct comparative evaluations while consulting the manual as needed.