6 Steps to Configure Shading in the PVSyst Manual

Table of Contents

• What I want to understand first about PVSyst's shading settings

• Problems That Occur When You Postpone Obstruction Settings

• Step 1 Separate occluders into distant shadows and nearby shadows

• Step 2: Set azimuth, tilt, and system conditions first

• Step 3 Organize on-site information in a form that can be converted into 3D

• Place obstructions and PV surfaces in Step 4 Near Shadings

• Step 5 Confirm shadow calculation methods and electrical effects

• Step 6 Compare the results and use them to inform design decisions

• Common mistakes when configuring obstructions

• Tips for Using the PVSyst Manual Effectively in Practice

• Summary

What to Understand First About PVSyst's Shading Settings

Many people consulting the PVSyst manual about shading settings are not merely looking for operational steps; they also want to understand how shadows are reflected in the simulation results, how detailed the inputs should be, and how the specified obstructions affect energy yield and loss rates. In photovoltaic simulations, even if panel capacity, meteorological data, azimuth, tilt, and PCS conditions are all set, overlooking shadows from surrounding buildings, trees, rows of mounting structures, mountain ridgelines, or equipment can easily create discrepancies between actual generation and the analysis results.

In the official PVSyst documentation, shadows are broadly explained by dividing them into distant shadows and nearby shadows. Distant shadows are the concept that deals with whether the sun is visible to the entire PV surface, such as the horizon or distant mountains. On the other hand, nearby shadows are shadows cast by nearby objects onto part of the PV surface, and because they require detailed 3D representation, they are handled more complexly than distant shadows.

This article organizes the points that tend to cause confusion when proceeding with shading settings in the PVSyst manual into 6 steps aligned with the practical workflow. Rather than memorizing screen names or concepts by rote, the goal is to understand why you check things in that order, at which stages mistakes are likely to occur, and which final results you should look at to inform design decisions.

The important thing when setting obstructions is not to try to create a perfect 3D model from the start. First, separate the types of shadows; next, set the basic conditions such as the orientation and capacity of the PV surface; then model the dimensions and positions of the obstructions, run the shadow calculations, and finally check the plausibility of the losses. Simply following this sequence can greatly reduce setup errors, double counting, longer calculation times, and misreading of the results.

Problems That Arise When Postponing Obstruction Settings

In solar power system design, checking for shading is sometimes postponed. People tend to think it's fine to enter capacity, strings, PCS, and weather data first, and add shadows at the end. However, in PVSyst, shading settings are related to PV surface orientation, array layout, number of modules, the 3D scene, and the calculation method, so trying to set them all together at the end often leads to rework.

For example, in a rooftop project, if shadows from adjacent buildings or rooftop structures are entered later, some of the modules in the planned layout may become heavily shaded. In ground-mounted projects, once mutual shading between racking rows is taken into account, it may be necessary to reconsider row spacing and tilt angle. In mountainous or sloped terrain, confusing distant terrain shading with shadows from nearby equipment can make it difficult to identify which losses are caused by which factors.

PVSyst's Near Shadings is the central screen for handling near shading, and the workflow is to construct the entire scene using the 3D editor. The official documentation also shows that the Near Shadings main dialog is the dashboard for near-shading processing, and that you open the 3D editor from Construction/Perspective to create the scene.

Therefore, shading settings are not merely a post-processing step. From the earliest stages of design, you need to decide what level of accuracy to use for shading, which obstructions to input, what to model in 3D, and which elements may be simplified. When reading the PVSyst manual, it is important to understand not only where the buttons are but also the design decisions to be made before entering data.

Step 1 Separate occluders into far-field and near-field shadows

The first step is to divide shading objects into far-field shadows and near-field shadows. If you start the setup with this classification left ambiguous, you may end up modeling in detail elements that should not be included in the 3D scene, or conversely oversimplifying nearby buildings and rows of mounting racks, disrupting the balance between result accuracy and workload.

Examples of objects that are convenient to treat as distant shadows include mountain ridgelines, distant hills, and distant clusters of buildings. These are major factors in determining whether the sun is blocked for the entire PV surface. Because they are far away, they influence the system in the form of whether solar irradiance reaches the surface at a given solar altitude and azimuth, rather than by having the shadow boundary move finely across the panels.

Items that should be treated as near-field shading include adjacent buildings, rooftop penthouses, parapets, trees, utility poles, fences, adjacent racking rows, equipment panels, electrical cubicles, and ventilation equipment. These cast shadows on parts of the PV surface, and the shadow positions change with the time of day and season. For near-field shading, which part of the panel surface is shaded becomes important, and in some cases this can affect electrical mismatch losses.

In PVSyst's documentation, the Shading Factor for near shading is described as the ratio of the shaded area to the total effective area of the PV field. Also, the treatment of near shading is considered more complex than that of far shading because it requires detailed 3D descriptions.

In practice, it is important not to try to input all obstructions at the same level of detail. Objects far from the generation surface whose shadow contours have little effect are classified as distant shadows. Objects close to the generation surface whose shadows cross part of a panel are included in the 3D scene as near-field shadows. By making this distinction up front, you can reduce work time while concentrating on the parts that affect the results.

Especially in large-scale ground-mounted projects, treating mutual shading between racking rows and shading from surrounding terrain and trees in the same way causes confusion. Mutual shading between racking rows creates shadows on parts of the power-generating surface and should be treated as near-field shading, whereas distant mountains and hills are more naturally treated as far-field shading. In rooftop projects, parapets, penthouses, and adjacent buildings tend to be near-field shading, while distant high-rise buildings and obstacles on the horizon should be handled differently depending on the conditions.

Step 2: Set orientation, tilt, and system conditions first

The next step is to roughly configure azimuth, tilt, PV surfaces, number of modules, subarrays, and the system configuration before inputting obstructions. Even if you fully build out the obstruction settings first, the alignment with the 3D scene will be disrupted if the PV surface orientation or module count changes later.

In PVSyst, when defining a 3D scene, the direction defined on the variant side in Orientation and the effective PV area and number of modules defined on the System side must match. If the mismatch exceeds the allowable tolerance, the simulation may not be able to run.

This point is very important when reading the PVSyst manual. Shading settings are not independent decorations but inputs tied to the design conditions. If you create detailed shading objects before the PV surface orientation, tilt, array segmentation, and module layout are finalized, consistency errors and the need to reconfigure are likely to occur later.

In practice, it's easier to proceed by first creating a baseline case with no shading. Set the weather data, installation azimuth, tilt, modules, PCS, and string configuration, run the simulation without any obstructions, and check the baseline values. Then create a case with obstructions and compare energy production, PR, loss diagrams, and monthly results. This method makes it easier to determine how much the obstructions changed the results.

Additionally, preparing the design conditions before configuring obstructions helps when explaining to stakeholders. The no-shadow case shows power generation close to an ideal layout, while the shadowed case shows power generation that reflects actual site conditions. If you can explain the differences between the two, you can concretely discuss measures such as changing row spacing, revising module placement, defining non-installation zones around obstacles, and the need for tree removal or relocation.

What you should avoid at this stage is detailing the 3D scene while system conditions remain undecided. Even if you create detailed models, you'll need to readjust them if the definition of the PV surface changes. When working with the PVSyst manual, keeping in mind to verify the consistency of Orientation and System before Near Shadings will stabilize the subsequent steps.

Step 3: Organize on-site information into a format that can be converted into 3D

The third step is to organize the site information in a form that can be incorporated into a 3D model. One common cause of failure in obstruction settings is placing objects intuitively while looking at site photos or drawings. To reproduce shadows in PVSyst, you need to organize as concretely as possible the obstruction height, width, depth, distance from the PV surface, azimuth, ground level difference, and the relationship to the mounting surface.

For rooftop projects, we check parapet heights, rooftop penthouse dimensions, the heights of outdoor air-conditioning units and ducts, the distance to adjacent buildings, the roof slope, and the layout area of the PV surface. For ground-mounted projects, we clarify the height of racking rows, their tilt, row spacing, the relationship between front and rear rows, surrounding trees and fences, nearby buildings, and differences in ground elevation. On sloped sites, not only the simple plan layout but also elevation differences and the slope direction affect the results.

For inputting into PVSyst, it is easier to think of site information divided into "objects that cast shadows" and "PV surfaces that receive shadows." Objects that cast shadows include buildings, walls, columns, trees, and rows of mounting structures. PV surfaces that receive shadows are the surfaces on which modules are placed. If the positional relationship between the two is ambiguous, shadows may look plausible on-screen but the timing of shadow occurrence and the amount of loss will not match what is observed on site.

At this stage, you do not need to create a perfect architectural model. Rather, it is important to simplify with priority given to the contours that cast shadows onto the power-generation surface. Even if you reproduce complex equipment shapes in detail, if they have little effect on the shadow outlines or heights in the results, you will only increase computational load and work time. Conversely, elements that look small—thin columns, fences, or power lines—that produce long shadows in the morning and evening require attention.

In on-site surveys, do not rely solely on photographs; it is important to document the basis for dimensions. Combine plan drawings, elevation drawings, site layout drawings, survey results, roof plans, drone photos, on-site notes, and so on, so that you can explain which values were entered into PVSyst. If you are later asked about differences in energy production or shading losses, having the supporting evidence makes it easier to explain the validity of the settings.

Before checking the operations in the PVSyst manual, organizing these input materials in advance will significantly reduce the time you spend navigating the interface. You can consider that the quality of the shading settings is determined not only by how you operate the software but largely by how well you organize on-site information before data entry.

Step 4 Place obstructions and PV surfaces in Near Shadings

The fourth step is to create a 3D scene in Near Shadings and place the obstructions and PV surfaces. This is the part of the PVSyst manual where you will most want to check the procedures. In Near Shadings, PV surfaces and surrounding objects are positioned in 3D space so that the effects of near shading can be calculated.

In PVSyst's Near Shadings main dialog, open the 3D editor from Construction/Perspective and build the entire scene. When a valid 3D scene is completed, the program verifies that the orientation of the 3D field matches the definition on the Orientation side and that there is a sufficient and reasonable 3D area to place the modules defined on the System side.

The basic procedure is first to place the PV surface correctly, and then to arrange the surrounding obstructions. If you add obstructions while the PV surface's position or orientation is off, the shadow results will not be correct. In particular, the interpretation of azimuth, the tilt angle, the orientation of the coordinate axes, and the origin position are points that can easily lead to large differences later on.

When creating shading objects, prioritize shapes that effectively cast shadows rather than perfectly reproducing the on-site appearance. For adjacent buildings, the outline and height that cast shadows on the PV surface are more important than roof details. For parapets, height and distance from the PV surface are more significant than thickness. Because trees have seasonal variation and translucency, decide on a case-by-case basis whether to treat them as fully solid or to take a conservative view.

For ground-mounted racking rows, the relationship between row spacing and tilt angle is important. Check during which times shadows from the front row fall on the rear row, and revise the row spacing or installation angle as necessary. In PVSyst, there is a simplified method for handling mutual shading of racking rows and a method for explicitly defining them as PV surfaces within the Near Shading scene. The official documentation also explains that for the mutual shading of sheds there are two approaches: defining it on the Orientation side and defining it as PV surfaces in the Near Shading scene, and warns that using both at the same time can cause shadows to be accounted for twice.

This double-counting is a mistake that very often occurs in practice. If you set inter-row shading on the Orientation side but also include the same racking rows as shading elements on the Near Shadings side, losses can be overestimated. Conversely, if you include only surrounding buildings in Near Shadings and do not set mutual shading between racking rows anywhere, losses can be underestimated. It is important to be clear about which shadows are handled by which function.

When you create a 3D scene, always change the viewpoint and check it. Even if it appears correct in plan view, there can be discrepancies in the vertical direction. Verify the positional relationship between the PV surface and obstructions from the front, the side, an oblique angle, and from above. For projects where morning and evening shadows are important, even slight differences in an obstruction's height or distance will change how the shadows extend.

Step 5 Verify shadow calculation methods and electrical impacts

The fifth step is to verify how shadows are calculated and how electrical effects are handled. Simply placing obstructions in a 3D scene does not necessarily mean you can interpret the results correctly. In PVSyst, the interpretation of the results changes depending on whether shadows are treated as a simple irradiance loss or whether electrical mismatches according to string and module layout are also taken into account.

In PVSyst’s official documentation, for the beam component of near shading it distinguishes between losses due to reduced irradiance and losses due to the electrical response of series-connected modules and parallel strings. It also explains that, for handling electrical losses, there are two approaches: an approximate estimate using a Shading factor per string, and a detailed electrical calculation based on module positions.

If you look at the results without understanding this difference, you cannot explain why shading losses may appear small or large. For example, even with the same shaded area, the electrical impact differs between a shadow that only slightly covers the edge of a module and one that falls on critical parts of cells or modules connected in series. Judging solely by a simple area ratio can underestimate the actual loss in output.

On the other hand, it is not always best to use the most detailed calculations. Detailed settings require accurate input of module layout and string configuration. In the early design comparison stage, one approach is to first look at trends using linear shading loss and then, once the candidate options have been narrowed down, examine electrical shading effects in detail. For large-scale projects, it is also necessary to consider the balance with computation time.

In PVSyst, a Shading Factor Table is created and used to account for the effects of shading in the calculations. The official documentation explains that the Shading Factor is the fraction of the PV field’s area shaded for a given sun direction, with 0 meaning no shading and 1 meaning fully shaded. It also describes the concept of a Fast calculation, which interpolates from precomputed values on a grid of solar altitude and azimuth to reduce computation time, and a Slow calculation, which is computed at each simulation step.

In practice, it is easier to understand if you first compare a no-shading case, a linear-shading case, and, if necessary, a case that includes electrical effects. If losses are large, check which month, which time of day, and which obstructions are responsible. Distinguish whether the losses are concentrated in winter mornings and evenings, whether a particular row is shaded year-round, whether the shading is from nearby buildings, or whether it is mutual shading between racking rows.

At this stage, it is important not to judge the results by a single figure. Even if the shading issue appears small when looking only at annual generation, it can affect generation in specific months or output during peak hours. For self-consumption projects and projects that emphasize peak shaving, not only the annual value but also the time-of-day impacts are important. Even for projects that sell power, if it affects winter generation or guarantee conditions, the basis for the shading should be carefully verified.

Step 6 Compare results and use them to inform design decisions

The sixth step is to compare the results after configuring obstructions and use them to inform design decisions. Even if you complete the setup by referring to the PVSyst manual, that is not the end. What matters is determining how much the shading affected energy production, whether that loss is acceptable, and whether the design should be changed.

The first thing to check is the difference between the unshaded and shaded cases. We compare annual energy generation, PR, Specific Production, Shading loss, and monthly generation. If losses increase significantly in the shaded case, we will determine whether this is due to a 3D scene configuration error or because the actual site conditions are severe.

Next, check when the shadows occur. The design decision will vary depending on whether shadows appear only in winter, also in spring and autumn, or persist during summer mornings and evenings. If the shadows are unavoidable due to the low solar altitude in winter, they may be acceptable. On the other hand, if shadows appear during the main power generation hours throughout the year, layout changes or countermeasures against obstructions should be considered.

We also consider not only the magnitude of shading losses but the balance with mitigation costs. Widening row spacing may reduce shading losses but could reduce installed capacity. Removing trees may reduce shading losses but requires permits and consideration for the surrounding environment. Leaving areas around rooftop penthouses without panels may reduce shading losses but can lower total capacity. PVSyst results provide material to quantify these design decisions.

In large-scale projects, performing detailed calculations for all PV tables can be time-consuming. PVSyst provides an approach that performs shadow calculations limited to specific PV tables within the entire 3D scene and extrapolates those results to the whole. The official documentation explains that, when computation times are long for large projects or when you want to focus on particular parts, you can use the Partial shadings calculation.

However, when using partial calculations, you must carefully consider whether the selected area is representative of the whole. If shadows occur uniformly across rows of mounting racks, it may be easy to use a representative area, but if shadow conditions differ greatly between locations near surrounding buildings and those farther away, extrapolating from partial calculations may poorly reflect reality. Even as a convenient feature to shorten calculation time, caution is required when interpreting the results.

Ultimately, the PVSyst results are checked against the design drawings and on-site conditions. If shading losses are larger than expected, verify the PV surface position, obstruction heights, azimuth, units, coordinates, row spacing, and whether any double-counting has occurred. The same applies if shading losses are much smaller than expected. Even if obstructions were intended to be included, possible causes include the shadow-casting setting being disabled, a misalignment in the positional relationship with the PV surface, or incorrect handling of far-field versus near-field shading.

Common mistakes in obstacle settings

Even when configuring shading objects using the PVSyst manual, several typical mistakes occur in practice. The most common is confusing far-field and near-field shading. If you model distant mountains as detailed 3D shading objects, or conversely treat nearby buildings as a simple horizon, you will not be able to accurately reproduce the actual shading conditions.

The next most common issue is inconsistencies with Orientation and System. If the PV surface in the 3D scene does not match the azimuth, tilt, effective area, and number of modules defined on the variant side, errors can occur before calculation or the results can become unclear. Because PVSyst cross-checks the 3D scene against the system definition, consistency is important not only for obstructions but also for the PV surface itself.

Double counting is another easy-to-overlook mistake. If the mutual shading between racking rows is handled on the Orientation side but the same shading is also entered on the Near Shadings side, losses will be overestimated. Especially for ground-mounted projects, multiple shading factors overlap, such as inter-row shading, nearby buildings, terrain shading, and fence shading. It is important to keep a record of which function is representing what.

Errors in dimensions and units can also have a major impact on the results. Mistakes such as entering a height as if it were in a different unit when it should be entered in meters, interpreting the orientation reference in reverse, confusing distances on drawings with actual distances, or ignoring height differences on roof planes can be hard to notice from appearance alone. Even if it looks plausible in the 3D view, if the shadows fall or extend unnaturally you should question the settings.

Another common mistake is modeling shading objects in excessive detail. If you try to include every piece of equipment, piping, handrail, and racking component in detail, work time increases and the calculations become heavier. It is important to separate elements that affect the results through shading from those that are only for appearance. PVSyst is a simulation tool for design decision-making, not intended for creating architectural CG.

Finally, a common mistake is to limit result verification to annual values only. Even if annual shading losses are small, they can be concentrated in specific months or time periods. For projects where self-consumption or generation during peak hours is important, time-of-day shading impacts are highly significant. After configuring obstructions, check not only annual energy production but also monthly results, loss diagrams, and shading-related outputs.

Tips for Mastering the PVSyst Manual in Professional Practice

When using the PVSyst manual in practice, it is important not simply to follow the procedures literally, but to read and interpret them in the context of your own project. The examples in the manual are a starting point for understanding, but in real projects the roof shape, racking rows, topography, neighboring buildings, trees, equipment, design phase, and required level of accuracy all differ.

Start by creating a baseline case with no shading. Without a baseline case, you cannot evaluate the difference after introducing obstructions. Next, create a simplified case that includes only the major obstructions. Rather than modeling details immediately, incorporate the large obstructions that are likely to affect power output first. Then, add details as needed and check how much the results change.

This step-by-step approach has another advantage. When shading losses suddenly increase, it becomes easier to trace which input caused it. If you enter all obstructions at once, it becomes difficult to identify the cause even if the results change. Saving the results at each stage — after adding buildings, after adding racking rows, after adding trees, and after enabling electrical effects — makes verification easier.

Also, it is important to verify PVSyst results together with on-site photos and drawings. Looking only at the simulation results can make the numbers look consistent, but they are meaningless if they do not match the actual site conditions. Confirm that the north and south sides of the PV surface have not been swapped, that the heights of obstructions match reality, that the orientation of the racking rows matches the drawings, and that ground level differences have not been ignored.

When explaining to stakeholders, simply saying "power generation dropped because an obstruction was introduced" is insufficient. You should be able to explain which obstruction, during which period, and to what extent it had an impact, and as a result how annual energy production and PR changed. If design changes are needed, comparing several options — for example widening row spacing, staggering the layout, leaving heavily shaded areas uninstalled, or implementing measures to mitigate obstructions — will make decision-making easier.

The purpose of learning shading settings in the PVSyst manual is not just to memorize screen operations. It is to connect design conditions, site conditions, types of shadows, calculation methods, and result interpretation so as to make reproducible judgments. In particular, for projects involving power generation guarantees or profitability evaluations, being able to explain the rationale for the shading settings is essential.

Summary

When progressing with shading settings in the PVSyst manual, start by distinguishing between far shading and near shading. Far shading refers to shadows that affect the entire PV surface, such as the horizon or distant mountains; near shading refers to elements that cast specific shadows on part of the PV surface, such as buildings or rows of racking. By making this classification first, it becomes clear which functions to use and to what extent 3D modeling should be applied.

Next, set the basic conditions such as azimuth, tilt, PV surface, number of modules, and subarrays. Because obstruction settings are linked to system conditions, it is important to first create a baseline case and confirm the results without shading. Then organize site information as dimensions, distances, heights, azimuths, and ground level differences, and construct the 3D scene in Near Shadings.

In 3D scenes, accurately representing elements that affect shading is more important than reproducing appearance. Organize mutual shading between rows of racking, surrounding buildings, rooftop structures, parapets, trees, etc., and avoid double-counting or missing inputs. After placing obstructions, check the Shading Factor Table and calculation methods, and interpret the results with an understanding of the difference between linear shading losses and electrical effects.

Finally, compare the no-shading case with the shaded case and determine whether design changes are necessary by reviewing annual energy production, monthly results, PR, and loss diagrams. Obstruction settings are not simply a matter of entering losses; they are an important process for reflecting site conditions in the design and for explaining the validity of the energy yield.

When using the PVSyst manual, it's important not simply to follow the screens but to understand the entire workflow—from shadow classification, the rationale for inputs, the consistency of the 3D scene, calculation methods, to the interpretation of results. By proceeding through these six steps, you can reduce uncertainty in obstruction settings and move closer to simulation results that are easy to explain in practice.