7 Practical Steps to Conduct Shading Analysis Using the PVSyst Manual

Table of Contents

• What you should understand first about shading analysis in PVSyst

• Practical Step 1：Clarify the analysis objectives and scope

• Practical Step 2: Align azimuth, tilt angle, and layout conditions

• Practical Step 3: Consider near shadows and distant shadows separately

• Practical Step 4: Create a 3D Scene and Recreate Obstacles

• Practical Step 5: Confirm the Timing of Shadow Occurrence and Seasonal Variations

• Practical Step 6: Verify shading losses with simulation results

• Practical Step 7: Proceed with design revisions and report preparation

• Common pitfalls in PVSyst shading analysis

• Approach to Applying the PVSyst Manual in Practical Work

• Summary

What You Should Understand First About Shading Analysis in PVSyst

In the design of a photovoltaic (PV) system, shadow analysis is a critical step that greatly influences the reliability of energy production simulations. Even if module and inverter capacities are entered carefully, if shadows from surrounding buildings, trees, utility poles, fences, adjacent arrays, and between racking rows are not properly accounted for, the projected annual energy yield will diverge from reality. The purpose of consulting the PVSyst manual when conducting shadow analysis is not merely to learn the software interface, but to judge which shadows should be modeled and to what level of accuracy, and to perform loss assessments that can be explained during the design phase.

In PVSyst, shadows are broadly treated as either those from distant terrain and the horizon, or as near shadings—shadows cast onto the module plane by objects located close to the PV installation. In PVSyst's official documentation, Near shadings are described as cases where nearby objects cast visible shadows on the PV field, and the calculation of near shadings requires a detailed 3D description that includes the PV system and the surrounding environment.

In practice, what you should be particularly careful about is not to consider shading analysis as an "auxiliary task to be checked at the end." The effects of shading relate to array layout, row spacing, rack height, tilt angle, the series-parallel configuration of modules, MPPT partitioning, string design, and even future maintainability. Therefore, when carrying out shading analysis in PVSyst, you should not calculate energy production first and then add shading afterward; rather, you need to consider the layout with shading in mind from the initial design stage.

Also, when reading the PVSyst manual, it is important not to follow only the shading analysis screen piecemeal, but to understand project settings, azimuth and tilt angles, the 3D scene, the shading table, loss diagrams, and report output as a unified workflow. In this article, for people who use the PVSyst manual in practice, we organize the approach and checkpoints into seven steps so they can carry out shading analysis without hesitation.

Practical Step 1: Define the analysis objectives and scope

The first step in shading analysis is not opening PVSyst and creating a 3D model. What you should do first is clarify what you want to verify with this simulation. For example, whether you want to see a rough impact on annual generation at the estimation stage, compare shading losses for each array layout in a design comparison, or prepare a documented, explainable basis to submit to financial institutions or clients will determine how detailed the model needs to be.

For low-voltage roof-mounted projects, surrounding parapets, adjacent buildings, antennas, outdoor air-conditioning units, chimneys, and rooftop equipment are the main shading factors. For ground-mounted industrial projects, self-shading between racking rows, surrounding trees, slopes, fences, transmission equipment, neighboring buildings, and structures that may be built in the future need to be checked. In agrivoltaic solar installations, because support posts, crop management space, racking height, and row spacing affect both shading analysis and the agricultural environment, you need to consider not only power output but also how much sunlight remains for the crops.

At this stage, it is important not to try to enter all shading objects with the same level of detail. Prioritize objects that may cast shadows on the generating surface for long periods, that have a large impact at the low sun angles around the winter solstice, that cast shadows during the morning and evening generation hours, or that could affect an entire string. Conversely, objects that are sufficiently far from the generating surface and have little effect, or small objects that cast shadows only for short periods, can be simplified in the initial stage.

When using the PVSyst manual in practice, the goal is not to fill in every field available on the screen. It is important to select information that is necessary and sufficient for the objective, and to be able to explain later how detailed your modeling was. If you clarify the analysis purpose, scope, shading factors you excluded, and any conditions you simplified at the outset, interpreting the simulation results will be easier.

Practical Step 2: Align the azimuth, tilt angle, and placement conditions

The accuracy of shading analysis is not determined solely by how detailed the 3D scene is. If fundamental parameters — azimuth, tilt angle, array layout, racking height, row-to-row spacing, module dimensions, etc. — do not match the actual design conditions, then no matter how carefully obstacles are entered, the way shadows appear will not be reproduced correctly. When handling PV fields in PVSyst, the approach shows that conditions such as azimuth, number of tables, layout, pitch, and so on should be defined for each field.

In practice, while cross-checking design drawings, layout plans, single-line wiring diagrams, mounting rack drawings, site survey photos, and survey data, we align the input conditions in PVSyst. For roof-mounted installations, it is important not to determine the roof surface azimuth and tilt angles solely from architectural drawings but to corroborate them with measured values, aerial photographs, and on-site verification information. For ground-mounted installations, confusing the site’s true north, the north shown on drawings, and magnetic north will cause the array’s orientation relative to the sun’s path to be off.

Especially in shadow analysis, a few degrees' difference in azimuth or a difference of tens of centimeters (tens of inches) in height can affect shadow length in the morning, evening, and during winter. Some rounding may be acceptable for early-stage, rough estimates in the initial design, but for final reports or studies close to generation guarantees, you should make clear which values you used as the basis. In addition to confirming that the values entered in PVSyst match the values on the design drawings, also confirm which drawing revision was used and whether the updated layout has been reflected.

Also, in shading analysis, not only the arrangement of the array itself but the electrical segmentation is important. The same shade can produce different effects at the module, string, or MPPT level. In practical PVSyst use, it is essential not to stop at simple geometric shading loss but to consider how much that shading leads to electrical mismatch.

Practical Step 3: Consider near and distant shadows separately

A common source of confusion when learning shading analysis in the PVSyst manual is the difference between near shading and far shading. Far shading is a concept that deals with the sun being obscured by mountains, terrain, distant groups of buildings, or irregularities in the horizon. By contrast, near shading is the phenomenon where objects located close to a module cast distinct shadows on parts of the module’s power-generating surface. Although both are the same “shading,” the methods for modeling them and the way the results are interpreted are different.

Far-field shading mainly concerns whether the sun is visible or not. For example, if there is a mountain to the east, sunlight may be blocked for a certain period in the morning. If there is high terrain to the west, power generation in the evening may decrease. Such shading is often assessed by the relationship between the sun’s path and the horizon, and is considered more in terms of whether sunlight reaches the entire installation than as shadows falling on part of individual modules.

Near Shadings are more complex. Adjacent array rows, roof upstands, building façades, trees, utility poles, and the like cast shadows onto specific modules at particular times of day. In PVSyst’s official tutorial, Near Shadings is cited as one of the more difficult parts, and the workflow shown proceeds from defining the 3D scene.

In practice, mixing distant shading and nearby shading in the same assessment can easily lead to incorrect judgments. For example, the issue of reduced morning generation caused by shadows from mountains and the issue of some strings dropping out during winter mornings due to shading from adjacent arrays require different countermeasures. The former is often something that must be accepted as a site condition, whereas the latter may be improved by reexamining inter-row spacing, racking height, module layout, and string segmentation.

When proceeding with analysis in PVSyst, it is practical to first check the site's overall solar access for far shading, and then evaluate specific nearby obstructions around the installation for near shading. Rather than looking at only one and concluding "shading losses are not a problem," separating and checking the characteristics of each makes it easier to identify potential opportunities for design improvement.

Practical Step 4: Create a 3D Scene to Recreate Obstacles

The central task for evaluating near shading is creating the 3D scene in PVSyst. PVSyst’s Near Shadings dialog is positioned as the dashboard for near shading processing, and it shows the workflow of opening the 3D editor from Construction/Perspective to create the scene.

In a 3D scene, place the PV field, buildings, trees, walls, roofs, ground, and surrounding obstructions so that their positional relationships are close to reality. What matters here is accurately reproducing the geometric relationship between the surfaces that cast shadows and those that receive them, rather than aesthetic appearance. Prioritize correctly entering the height, width, position, orientation, and distance that create the shadows over detailing the appearance of buildings.

For example, on rooftop installation projects, the relationship between the parapet height and the height of the module’s lower edge is important. Even if the parapet appears low, if the module is close to the roof surface it can cast long shadows during winter mornings and evenings. In ground-mounted projects, the inter-row pitch, the tilt angle of the racking, and whether the height of the front row casts shadows onto the lower part of the rear row are important. On sloped sites, ignoring differences in ground elevation can cause evaluations of inter-row shading to differ from actual conditions.

When creating a 3D scene, rather than aiming for a perfect model from the start, a practical approach is to input elements step by step, beginning with those that have the greatest impact. First place the PV field correctly, then position buildings and major obstructions, and afterward add fences, trees, and equipment. By changing the sun position at each stage and checking how shadows fall, you can more easily identify which obstructions are the primary causes of loss.

Also, a PVSyst 3D scene is not a CAD model that reproduces the design drawings exactly, but a shadow-analysis model required for power generation simulation. Therefore, it is necessary to decide to omit certain details. For example, rather than modeling a complex-shaped building with many small faces, representing the exterior form that affects shadows as a simple solid can reduce input errors and make it easier to explain later.

Practical Step 5: Verify the times when shadows occur and their seasonal variations

Once you have created a 3D scene, the next thing to check is when, where, and to what extent shadows occur. In shadow analysis, it is important not to focus solely on the annual loss rate, but to verify seasons with low solar altitude, morning and evening time periods, and how shadows extend in specific months. Shadows that appear minor in annual values can have significant practical implications for projects where winter generation is important or where they overlap with self-consumption demand periods.

Pay particular attention to the morning and afternoon around the winter solstice. Because the sun's elevation is low and shadows tend to stretch long, inter-row shading and shadows from surrounding buildings are more likely to occur. For ground-mounted arrays, check whether the shadow from the front row falls on the lower parts of the modules in the rear rows. For rooftop installations, check which strings and at what times shadows from parapets and rooftop equipment will fall.

Also, do not overlook the transitional periods in spring and autumn. Even if shadows are not as long as at the winter solstice, if they occur during seasons when power generation is relatively high, their impact on annual generation can be non-negligible. In summer, the sun’s altitude is high and shadows tend to be short, but in the morning and evening shadows from surrounding objects can stretch at an angle. Because the shape of shadows changes with the seasons, it is risky to judge based on a single date and time.

In PVSyst, 3D scenes are used to examine shading depending on the sun’s position and to incorporate the effects of shading into the calculations. The shading table is described as being used for shadow-scene analysis and as relating to shading coefficients for the diffuse and albedo components, iso-shading maps, and accelerated calculations during simulation.

In practice, creating a shading table is not the end; you need to verify that the results are consistent with on-site observations. For example, if photos of the site clearly show a large building to the south but the simulation shows almost no shading losses, there may be errors in the building’s azimuth, distance, height, the PV field’s location, or the north orientation setting. Conversely, if an object that should have little impact in reality produces large losses, you should recheck its dimensions and placement.

Practical Step 6: Validate shading losses with simulation results

After checking the shape of the shadow, the next step is to verify the shading losses as outputs of the power generation simulation. What’s important here is not to consider the shadow’s appearance and the loss rate separately. Even if a shadow appears on the 3D view, if the solar irradiance at that time is low, the annual loss may be small. Conversely, even a short-duration shadow can have a large impact if it coincides with times or seasons of high power generation.

In the PVSyst results screen, you check how shading losses affect energy production together with other losses. By viewing them alongside temperature losses, wiring losses, mismatch losses, inverter losses, soiling losses, and so on, you can determine whether shading is a major loss factor or within an acceptable range for the design. It is important not to evaluate shading losses in isolation but to place them within the overall loss structure.

Also, for near shading, it is necessary to consider not only the geometrical area affected by shadows but also the electrical impacts. PV modules can affect an entire string or an MPPT input even if only part of a module is shaded. PVSyst’s Electrical shadings section shows that, in the Module Layout, you can view the actual shading on the table for the selected MPPT input and the I/V curves of the shaded PV modules.

In practice, the important thing is not to accept the shading loss rate figure at face value, but to interpret it in a way that informs design decisions. For example, even if the annual shading loss is small, if it is concentrated on particular strings it can affect long-term generation decline and the detection of anomalies in monitoring. Conversely, if the shading is spread thinly and broadly and does not significantly interfere with the main power-production periods, it may be acceptable from a design perspective.

When validating simulation results, it can also be effective to compare multiple scenarios. By comparing a scenario with slightly wider row spacing, one that changes the tilt angle, one that alters the module layout, and one that adjusts string division, you can assess the balance between reduction in shading losses and land-use efficiency. In solar design, eliminating shading losses entirely is not always optimal. Decisions should be made comprehensively, taking into account site area, system capacity, constructability, cost, and maintainability.

Practical Step 7: Proceed with Design Revisions and Report Generation

The ultimate purpose of shading analysis is not to run simulations, but to translate the results into design decisions and explanatory documentation. If shading losses are large, we review array layout, inter-row spacing, racking height, tilt angle, number of modules, string configuration, and clearance from obstacles. For rooftop installations, it may be necessary to consider removing modules in areas prone to shading, separating them onto a different MPPT, or changing the installation area.

In ground-mounted installations, widening the row spacing to reduce inter-row shading may decrease the capacity that can be installed on the same site. Therefore, it is necessary to compare which to prioritize: reducing shading losses or securing capacity. In particular, while increasing plant capacity increases annual energy production, overly tight row spacing can increase shading losses in winter. PVSyst’s shading analysis helps quantify and compare these design trade-offs.

In reports, merely writing "shading loss: X%" is insufficient. Make sure you can explain under what conditions the analysis was performed, which obstacles were entered, which shadows were excluded, and which design options were compared. For clients and internal reviewers, what matters is not whether PVSyst was operated, but whether the relationship between the input conditions and the results is reasonable.

In practice, it becomes easier to explain if you organize not only the PVSyst result report but also layout drawings, screenshots of the 3D scene, key dates and times when shading occurred, and the approach to comparing designs. If the shadow analysis results led to design changes, it is also important to keep the conditions before and after the changes; recording which proposal, which shadows, and to what extent they improved will be useful for later verification and for explaining to stakeholders.

What you should learn from the PVSyst manual is not just where the buttons are. Understanding how to apply shading analysis to design improvements, how to interpret the results, and how to explain them becomes a skill you can use in practice.

Common Pitfalls in PVSyst Shading Analysis

Common failures in PVSyst shading analysis stem more from insufficient clarification of underlying assumptions than from simple input mistakes. For example, the north direction on the drawing may be misaligned with PVSyst’s north, the roof azimuth may be entered in the opposite direction, the racking height may be confused as a height above ground rather than above the roof surface, or the distance to obstructions may be misread from the drawing scale. These discrepancies are problematic because they can look plausible on the simulation screen and are therefore difficult to detect.

Another common mistake is oversimplifying shadows. Simplification is useful during the estimation stage, but if you omit major shading factors the projected energy yield will be overly optimistic. In particular, buildings to the south, tall trees that cast shadows in winter, rooftop parapets, and inter-row shading from adjacent arrays should be accounted for from the early stages. Conversely, there is also the mistake of entering everything in excessive detail. If you model small items that have little to do with shading in complex detail, the model becomes unwieldy and it increases the risk of input errors.

Also, it can be dangerous to be reassured by looking only at the annual loss rate. Even if shading losses are small over the year, if they are concentrated in certain months or time periods they can affect power generation monitoring and self-consumption planning. For self-consumption systems, it is important whether shading occurs during periods of high demand. Even for systems focused on selling electricity, contracts or financial plans that emphasize winter generation require examining seasonal impacts.

Moreover, simply creating a 3D scene in PVSyst without checking the electrical impacts can also lead to failure. When part of a module is shaded, it can affect power generation beyond a simple area ratio. If the string configuration or MPPT division is not appropriate, a local shadow can lead to a widespread drop in output. Therefore, it is important to consider the shadow shape, time of occurrence, loss rate, and electrical configuration together.

Finally, insufficient explanations in reports are also a major issue in practice. Even if you attach only the PVSyst results, a third party cannot judge their validity if the input conditions are not known. In shading analysis, only by clearly stating what was input, what was omitted, and under which conditions comparisons were made does the document become usable as a basis for design.

How to Apply the PVSyst Manual in Practice

When reading the PVSyst manual, it is not enough to simply memorize the sequence of screen operations. What is required in practice is to understand at which points in the design decision process the functions described in the manual should be used. For shading analysis, for example, you should not view 3D scene creation, the shading table, loss results, electrical effects, and report output separately, but rather treat them as a single sequence of steps to improve the reliability of the estimated energy yield.

When beginners read the PVSyst manual, trying to understand all functions from the start can be confusing. It is useful to first go through the process of setting the project conditions, entering the azimuth and tilt angles, creating a simple 3D scene, and checking shading losses in the results. After that, expanding your understanding to the differences between near and far shading, electrical effects, comparing multiple design options, and interpreting reports will make it easier to apply the knowledge in practice.

If you are at an intermediate level or above, it is important to use shading analysis not merely as a checklist item but as a tool for design improvement. For example, compare how much shading losses are reduced when you change the row spacing, whether slightly reducing the system capacity improves the efficiency of annual energy production, and whether changing MPPT segmentation can mitigate the effects of local shading. PVSyst is software for quantitatively evaluating such decisions, and simply taking the numerical results at face value does not make full use of its true value.

Also, to make practical use of PVSyst shadow analysis in field work, the quality of on-site information is important. If the information before input—such as on-site photos, survey data, drone photos, drawings, information on surrounding buildings, tree heights, and post-development ground elevation—is inaccurate, the simulation results will also be uncertain. The more you become accustomed to operating PVSyst, the more likely you are to neglect verifying the source information, but in shadow analysis the accuracy of on-site information is directly linked to the results.

The PVSyst manual is a starting point for understanding the shadow analysis features. However, in actual projects you need to decide how detailed your inputs should be—based on the project’s purpose, design stage, submission recipient, and required level of accuracy—rather than simply following the manual. This judgment is the most important part of mastering PVSyst in practical work.

Summary

In practical work following the PVSyst manual for shading analysis, it is important to first clarify the analysis objectives and scope, and to correctly align the azimuth, tilt, and layout conditions. From there, separate far-field and near-field shading, recreate the main obstructions in a 3D scene, and check how shadows appear by season and time of day. Furthermore, validate shading losses from the simulation results, make design modifications as needed, and compile the findings into an explainable report.

What matters in shading analysis is not displaying shadows on the PVSyst screen. It is determining which shadows affect energy production, which shadows are acceptable, and which design changes are effective. By looking not only at the annual loss rate but also at seasonal and time-of-day variations and the relationships with the electrical configuration, shading analysis becomes a design review process to improve design quality rather than a mere verification task.

To apply the PVSyst manual in practice, it is essential to understand how operating procedures connect with design decisions. Shading analysis is a critical task that affects a photovoltaic system’s energy yield, layout, string design, and the credibility of explanatory materials. By using the seven steps organized here as a foundation, you can carry out shading analysis with PVSyst consistently—from initial studies through design comparisons to final report preparation.