8 Key Points Practitioners Should Know in the PVSyst Manual

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Table of Contents

• Basic approach to reading the PVSyst manual for practical work

• Grasp the concepts of projects and variants first

• Verify meteorological data and site conditions as the basis for the results.

• Azimuth, tilt, and array configuration are organized as design conditions.

• Do not base equipment selection and string design solely on capacity

• Do not leave the loss setting at its initial value; record the rationale.

• Check distant terrain and nearby shadows separately.

• Interpret the simulation results using PR and loss plots.

• Prioritize reproducibility in reports and internal sharing.

• Summary for applying the PVSyst manual to project work

Basic approach to reading the PVSyst manual for practical use

The purpose of reading the PVSyst manual is not merely to learn how to operate the software’s interface. What is important for practitioners is understanding which input values affect energy production, losses, PR, proposal documents, internal reviews, and client explanations, and creating a state in which reproducible assessments can be carried out for each project. In photovoltaic simulations, even with the same installed capacity, results change depending on how meteorological data, azimuth, tilt, string configuration, shading, losses, and grid-side conditions are handled. In other words, the PVSyst manual should be used not as a simple operating guide but as a practical reference to organize the order in which design conditions are checked and the points to watch when interpreting results.

PVsyst is positioned as PC software for the study, sizing, and data analysis of photovoltaic power generation systems, and it handles multiple applications such as grid-connected, stand‑alone, pumping, and DC grid systems. The official documentation also explains that it is a tool intended for architectural, engineering, research, and educational uses. In practical work, this breadth is convenient, but it also means there are many screens and configuration items, which can make it easy to be unsure where to start reading.

Therefore, rather than tracking every item in detail from the start, it is important to address in sequence the points that directly affect project quality. In particular, the eight items that practitioners should pay attention to are: project definition, meteorological data, orientation and tilt, system configuration, loss settings, treatment of shading, interpretation of results, and reporting. Understanding these eight points will enable you, when reading the PVSyst manual, to relate entries not just to screen names but to actual design decisions and documentation.

What you want to avoid when using the PVSyst manual in practice is a situation where filling in the input fields becomes an end in itself. A simulation returns calculation results based on the input conditions, and if the validity of those input conditions is weak, a visually neat report is still insufficient as a basis for design decisions. For example, if the reason for selecting the meteorological data remains vague, and orientation (azimuth) and losses are left at their initial values, judging quality only by PR at the end will make it difficult to explain when the work is later reviewed.

Practitioners must always keep three points in mind when reading the PVSyst manual: the meaning of the settings, their impact on results, and explainability. What does this setting represent? Which outputs will change if you alter this value? Can you provide justification when explaining it to colleagues or clients? Reading with this perspective makes it easier to apply the manual's content to project management, design reviews, and proposal preparation.

First, grasp the concepts of projects and variants

The first thing to understand in the PVSyst manual is the concept of projects and variants. In practice, it is common to compare multiple design options for a single project. Changing the orientation, changing the tilt, changing the PCS capacity, changing the array layout, changing loss conditions, adding shading effects, and so on—the conditions you want to compare vary widely from project to project. When organizing such evaluations, the distinction between projects and variants is extremely important.

The official documentation explains that a project is primarily a framework for holding geographical location and the meteorological data used in simulations, and that different simulation runs are organized as variants. It also positions project design as an area for conducting detailed simulations to perform the design and performance analysis of solar photovoltaic systems.

In practice, it is easier to understand if you think of a project as the common conditions of a case and variants as the design options under consideration. For example, when comparing, on the same site with the same meteorological data and the same basic site conditions, a 10-degree tilt option, a 15-degree tilt option, an east–west layout option, and an option with a different PCS capacity, saving each as a variant makes later comparison and explanation easier. Conversely, if you forcefully manage items with different case names or site conditions within the same project, the axes for comparing results become ambiguous and it is easy to get confused during review.

When reading the PVSyst manual, it is important to view variants not simply as saved files but as units that retain the history of your analyses. In practice, you seldom produce a finished design from the first draft; studies typically progress in stages such as checking basic conditions, adjusting equipment configuration, adding loss assumptions, assessing shading, and reviewing economics and P50 and P90. If you give variant names that make the contents of each study clear, it will be easier to trace later why a given result was obtained.

Even in the official tutorial, it first defines the initial system configuration with the minimum parameters, and then progressively adds far-field shading, near-field shading, detailed loss parameters, etc., showing a workflow in which each variant is saved and compared. This approach is highly effective in practice. Rather than including all conditions from the start, by adding conditions one by one and checking how much the results change, it becomes easier to explain the causes of power output reductions and the effects of design changes.

Especially in internal reviews, it is important to be able to explain not only the final results but also which conditions caused the outcomes to change. For example, the baseline design showed higher annual energy production, but adding nearby shading increased losses in certain months; changing PCS capacity altered how clipping was handled; and adjusting the tilt changed the winter generation trend. If you can verbalize the differences between variants in this way, you can communicate design judgments rather than just numerical reports.

Confirm meteorological data and site conditions as the basis for the results

The second point that practitioners must always check in the PVSyst manual is the meteorological data and site conditions. In photovoltaic power generation simulations, solar irradiance, air temperature, wind conditions, site elevation, and latitude/longitude, among others, affect the results. No matter how carefully the equipment configuration is set, if the selected meteorological data do not match the project conditions, the estimated power generation will be inaccurate.

In practice, when selecting meteorological data people tend to assume “it's nearby, so it’s fine.” However, in mountainous areas, coastal zones, basins, snow-prone regions, urban areas, and reclaimed land, solar radiation and temperature trends can differ even within the same region. When reading the PVSyst manual, you should aim not only to understand how to import meteorological data but also to be able to explain which location’s data you adopted and why that data is suitable for the project.

In PVsyst's project settings, you can set the search range for meteorological data files around the project site, and the official documentation explains the default values and the ranges that can be changed. This means that, while the software has a function to search for nearby data, deciding what range is appropriate requires judgment on a project-by-project basis.

When specifying site conditions, be careful about input errors in latitude and longitude and about mixing up coordinates. In particular, when handling multiple projects in succession, it is possible to leave the previous project's location information in place and fail to update it. Abnormalities in simulation results tend to be noticed in later stages, and if an error in the site conditions is found after report preparation, you will need to redo variant creation and revise documentation. To make practical use of the PVSyst manual, it is important not to neglect the initial site setup.

When checking meteorological data, do not rely solely on the magnitude of annual solar irradiation; you also need to examine monthly trends. Even if the annual values are similar, differences in the seasonal distribution between summer and winter can affect PCS selection, power sales planning, and alignment with demand-side consumption patterns. In particular, for self-consumption projects, not only annual generation but also monthly and time-of-day generation patterns influence the effectiveness of equipment deployment.

Also, confirming the source of the meteorological data and the timing of its updates will give you peace of mind during internal reviews and when explaining to clients. Practitioners should not only import the data following the procedures in the PVSyst manual, but also record as notes the name of the meteorological dataset used, the distance to the site, its representativeness, and whether any corrections were applied. Even if you do not include all of this in the final report, keeping it as internal documentation will make it easier to respond if you are later asked to verify the conditions.

Organize azimuth, tilt, and array configuration as design conditions.

The third point is orientation, tilt, and array configuration. The PVSyst manual includes items for setting the direction and tilt of the installation surface, tracking method, and racking conditions. These not only directly affect power generation but are also related to site conditions, constructability, maintainability, shading effects, snow accumulation, wind loads, landscape, and building constraints. In practice, it is necessary to organize the design conditions taking into account the constraints of the entire project, not just the angle that maximizes power generation.

In PVsyst 8, the concept of orientation has changed significantly, and the official documentation explains that it is now treated as a central element linking electrical-system sub-arrays with tables in the 3D scene. It also demonstrates the flexibility to combine fixed and tracking systems, multiple orientations, and various system types within a single project.

This point is important for practitioners. On rooftop projects, the orientation and tilt can differ for each roof plane. Even in ground-mounted projects, due to terrain, lot shape, site development plans, access paths, drainage, fencing, and neighboring-property conditions, it may not be possible to make all arrays under the same conditions. When reading the PVSyst manual, you need to be aware not only of the operations to set a single orientation and tilt but also of how to organize multiple surfaces and multiple sub-arrays.

When setting the azimuth and tilt, consistency with design drawings and layout plans is also important. If the angles set in PVSyst differ from the CAD drawings, layout planning, racking manufacturer documentation, or construction drawings, the relationship between the simulation results and the final design will become ambiguous. In particular, during the preliminary study stage a simplified layout is often used and the layout may change in the detailed design stage. In such cases, you should separate the old variant and the new variant and make clear which stage’s conditions they correspond to.

In array configuration, not only entering the number of modules but also how sub-arrays are divided, connection to the PCS, the number of strings, and the handling of different orientations affect the results. If multiple roof surfaces with different orientations are lumped together as a single condition, the actual generation trends and losses can become difficult to discern. Conversely, dividing them too finely makes management complex and increases input errors and difficulty in comparison. In practice, it is important to divide them into units that are meaningful for design.

When reading the PVSyst manual, it's useful to distinguish which settings directly affect energy production and which are involved in ensuring consistency with the 3D scene and shading calculations. Azimuth and tilt may appear simple, but the more complex the project becomes, the more they become important factors that determine how interpretable the results are.

Do not base equipment selection and string design solely on capacity

The fourth point is module, PCS, and string design. The PVSyst manual presents explanations about the component database and system definition. Practitioners should not only match the installed capacity numbers but also verify the voltage range, current, temperature conditions, PCS input specifications, number of strings, the approach to oversizing, and tendencies for clipping to occur.

When evaluating solar photovoltaic systems, the ratio of DC capacity to AC capacity has a major impact on proposals. Increasing DC capacity tends to raise energy output, but it can also increase the periods during which the PCS imposes output limits. Conversely, providing excessive margin can be disadvantageous in terms of equipment cost and site-utilization efficiency. When reading the PVSyst manual, you should not treat it merely as an equipment-selection task but should adopt an approach of verifying how changes in the DC/AC ratio affect the results.

In string design, check the open-circuit voltage at the lowest temperature, the operating voltage at the highest temperature, the PCS’s MPPT range, and input current limits. If warnings or inconsistencies appear on the PVSyst screen, it is important not merely to resolve them but to understand why they occurred. A warning indicates that there are points to check between the design conditions and the equipment specifications.

In practice, it is necessary to verify that manufacturer documentation and specifications fully match the database information within PVSyst. If there are devices with similar model numbers, modules with different power outputs, region-specific PCS, or differences between older and newer models, choosing incorrect data can reduce the reliability of the results. The PVSyst manual allows you to check how the database is handled, and it is prudent to include a cross-check with the equipment specifications adopted for the project in your internal procedures.

Also, in the early stages of design, assessments are made using preliminary equipment, which may be replaced by the final equipment at the proposal or detailed design stages. In such cases, it is necessary to avoid confusing the preliminary variant with the final equipment variant. When submitting reports, verify which equipment data were used for the results and whether they are consistent with the proposal documentation.

When reading the PVSyst manual for practical work, equipment selection should be regarded not as "items to input" but as a process for verifying the validity of the design. The perspective required of practitioners is to check not only whether the capacity is appropriate, but also the actual connections, temperature conditions, electrical constraints, output limits, and even the ability to justify the design in the future.

Do not leave loss settings at their default; document the rationale

The fifth point is the loss settings. This is an area that practitioners should pay particular attention to when reading the PVSyst manual. In photovoltaic simulations, various losses such as soiling, wiring, mismatch, module quality, temperature, IAM, shading, PCS efficiency, degradation, and grid-side constraints are reflected in the results. How these are configured can significantly change the annual energy yield and PR.

The official documentation also explains that detailed parameters such as thermal behavior, wiring, module quality, mismatch, incidence-angle losses, far shading, and near shading can be analyzed. It also states that the results include many simulation variables, and that loss diagrams are useful for identifying weaknesses in system design.

A common practical problem is finding yourself at a loss when later asked to justify settings that were left at their initial values. Initial values are convenient as a starting point for consideration, but they are not necessarily suitable for the project's conditions. For example, in coastal locations, areas near farmland, sites adjacent to factories, heavy-snow regions, areas with a lot of dust, or places where bird damage is a concern, the considerations for soiling and maintenance may need to be different.

The official PVsyst documentation explains that soiling loss can be defined with monthly loss coefficients because it strongly depends on rainfall. This indicates that seasonality can be taken into account, not just a uniform annual value. In practice, it becomes easier to explain how soiling losses were handled if you document them based on cleaning schedules, rainfall trends, installation angle, and the surrounding environment.

Wiring losses are also important. In preliminary studies it is common to proceed using estimated distances, but if the cable routing changes during detailed design the loss conditions can change. In particular for large-scale projects, the distances to combiner boxes, PCS, and substation equipment, the voltage class, and the cable sizes affect power output and economic performance. While checking how to set wiring losses in the PVSyst manual, it is also important to confirm that there are no inconsistencies with the actual design drawings.

In loss settings, being overly pessimistic or overly optimistic both cause problems. In proposal documents there is a temptation to show high power generation, but if the gap with actual results is large it undermines trust. Conversely, entering overly conservative values can make a project's profitability look poor and cause missed proposal opportunities. Practitioners need to set explainable loss conditions by combining internal standards, past projects, site conditions, and maintenance plans while referring to the PVSyst manual.

Check distant terrain and nearby shadows separately

The sixth point is the handling of shading. Even within the PVSyst manual, shading settings are an area where practitioners often stumble. Shading can be divided into far-field shading, caused by mountains or the horizon, and near-field shading, caused by buildings, trees, rows of racking, equipment, and nearby structures. Because their characteristics differ, they should not be treated collectively as the same 'shading' but should be checked separately.

The official documentation explains that near shading is caused by nearby objects that cast visible shadows on the PV field, and that its treatment is more complex than far shading, requiring a detailed 3D description of the entire PV system and the surrounding environment. It also indicates that near shading is one of the more difficult aspects within PVsyst, and that a tutorial for beginners is provided.

In practice, far-field shading is treated as an effect of surrounding topography and the horizon, while near-field shading is treated as an effect of layout planning and nearby obstacles. In mountainous areas, the influence of distant terrain can be significant and may affect solar radiation in the morning and evening and during winter. On rooftop projects, near-field shading from roof penthouses, parapets, outdoor air-conditioning units, adjacent buildings, antennas and similar elements tends to be problematic. For ground-mounted projects, items to check include array spacing, inter-row shading, fences, surrounding trees, utility poles, and slopes.

In near-field shadow settings, the level of detail in the 3D scene affects the results. However, in practice time is limited, so modeling everything in fine detail is not always the best approach. What matters is prioritizing obstacles that are likely to affect energy yield and distinguishing them from those with minimal impact. For example, tall buildings close to the array and objects that cast long shadows in winter should be given high priority, while distant objects with limited influence can often be simplified.

Also, for shading analysis it is necessary to reconcile the site layout plan, on-site photographs, survey data, the heights of surrounding buildings, and topographical information. Even if you create a 3D scene in PVSyst, if the source information is ambiguous the reliability of the results will be limited. Practitioners should not only check the operating procedures in the PVSyst manual but also organize the documentation that forms the basis for the shading settings and record which obstacles were taken into account.

The official documentation also explains that near-field shadows are calculated at each time step during simulations and may require different treatment for the direct, diffuse, and albedo components. This indicates that shadow settings are not simply a matter of area ratios, but are related to the computational model and how the results should be interpreted.

If shadows are handled incorrectly, not only the power generation but also the interpretation of monthly results and loss diagrams will change. When results show low generation in specific months, reduced output in the mornings and evenings, or large losses in winter, it is important not to simply conclude that PR is low, but to distinguish whether the cause is distant shading or nearby shading, the layout or the terrain, or the conditions of the 3D scene.

Interpreting simulation results using PR and loss diagrams

The seventh point is how to read the simulation results. After progressing through the settings while referring to the PVSyst manual, how the practitioner interprets the final output numbers is where their skill is demonstrated. Rather than looking only at the annual energy yield, it is necessary to read the results by combining PR, the loss diagram, monthly results, clipping, shading losses, temperature losses, wiring losses, and so on.

Regarding PVsyst's Performance Ratio, the official documentation states that for grid-connected systems PR is represented as E_Grid divided by the product of GlobInc and PnomPV, and it is described as a metric that includes optical losses, array losses, system losses, and so on. PR is a useful comparative indicator, but judging performance solely by PR without examining the breakdown of losses is risky.

If PR is low, the reasons depend on the project. Whether there are large temperature losses in high-temperature regions, significant shading effects, output limitations caused by the DC/AC ratio, large wiring losses, or whether soiling losses are being considered large, the appropriate countermeasures will differ. PR is a metric that summarizes the results, and to identify the cause you need to look at the loss diagram.

Loss diagrams help to understand at which stages and to what extent losses occur from the input solar irradiance to the final output. In practice, a loss diagram should be used not merely as an appendix page to a report but as a starting point for design review. For example, if shading losses are larger than expected, review the layout and obstruction conditions; if temperature losses are large, check the mounting arrangement and ventilation conditions; if wiring losses are large, reassess cable routing and voltage design.

Monthly results are also important. Even if the annual energy production is within expectations, if there is a large drop in a particular month you need to check shading, snow, solar irradiance data, angle/tilt conditions, output limits, and so on. For materials aimed at financial institutions and investors, and when evaluating self-consumption installations, monthly and hourly trends may be more important than annual values. When reading the PVSyst manual, don’t stop at merely checking the energy output on the results screen—confirm what level of result granularity can be produced, as this is useful in practice.

Furthermore, projects that handle P50 and P90 evaluations require explanations that include uncertainties, not just average simulation results. The official documentation explains that P50/P90 evaluations are a probabilistic approach for interpreting simulation results spanning multiple years, and that users must specify additional parameters that are not provided by the simulation.

This means that P50 and P90 are not determined absolutely with the push of a button, and that the assumptions about input uncertainties are important. Practitioners should not include only the P50 and P90 figures in their documents; they need to confirm which assumptions were used for the assessment and how climate variability and simulation uncertainty were handled. Especially when using them for investment decisions or long-term revenue projections, an explanation of the underlying assumptions is indispensable.

Prioritize reproducibility in reports and internal sharing.

The eighth point is reporting and internal sharing. The final step in putting the PVSyst manual to practical use is to communicate simulation results clearly to stakeholders and ensure they can be reproduced later. No matter how correctly you set things up, if the conditions that should be documented are missing, you will not be able to reproduce the same results when you review them later.

The official PVsyst documentation states that for each simulation run it can produce an engineer-oriented report that includes the parameters used and the main results. In practice, it is important not only to submit this report as-is but also to distill the key points for internal use and align them with proposal materials and study memos.

For internal sharing, the items we especially want to retain are the project name, site, meteorological data, equipment model numbers, DC capacity, AC capacity, azimuth, tilt, array configuration, major losses, treatment of shading, variant name, creation date, author, and review status. If these are organized, it becomes easier later to confirm “which conditions produced this power generation,” “what the differences are from alternative proposals,” and “whether it matches the materials submitted to the customer.”

Don't be satisfied with merely being able to operate PVSyst after reading the manual; as an internal rule, decide on variant naming conventions, storage locations, and report management so that the overall quality of the team remains stable. If each person uses different naming or storage methods, referring to past projects and handing them over will take time. Especially when multiple people handle a project, standardizing file management and explanatory materials is as important as PVSyst operational skills.

When explaining to a customer, you do not need to go through every overly detailed configuration item. However, you must clarify the key conditions that form the assumptions for the estimated power generation. For example: which meteorological data were used, whether shading was taken into account, whether loss assumptions are standard values or project-specific, and whether the equipment configuration matches the proposed equipment. If you can explain these points concisely, the credibility of the simulation results will increase.

Also, in internal reviews it is important to share not only positive results but also risks and uncertainties. Points such as shadow information being unconfirmed, equipment specifications being provisional, the representativeness of meteorological data requiring caution, and the possibility that layouts may change in the future should be shared early. Treating PVSyst results as definitive values can lead to trouble if conditions change during later stages.

The purpose for practitioners to read the PVSyst manual is ultimately to be able to explain the results. If the operation procedures, parameter settings, output results, and reasons for decisions are linked, you can produce persuasive documentation both internally and for clients.

Summary for Applying the PVSyst Manual to Project Work

The points that practitioners need to know from the PVSyst manual are not merely memorizing screen operations. Organizing projects and variants, verifying meteorological data and site conditions, understanding azimuth, tilt, and array configuration, equipment selection and string design, loss settings, far and near shading, how to read PR and loss diagrams, and the reproducibility of reports and internal sharing — mastering these eight items makes it easier to apply PVSyst to practical design studies and to the preparation of proposal documents.

What is particularly important is not to accept PVSyst’s calculation results as-is, but to be able to explain which conditions influenced those results. Rather than judging only whether the annual energy production is high or low, you need to perform an evaluation appropriate to the project while examining the meteorological data, tilt/azimuth, equipment configuration, losses, shading, output limitations, and monthly trends.

The PVSyst manual may feel information-heavy when you first read it. However, it becomes easier to understand if you read it following the practical workflow. First, organize the common conditions of the case as a project and save the proposals as variants. Next, check the site and meteorological data, and set the azimuth, tilt, and array configuration. Then arrange the equipment and strings, add losses and shading step by step, and finally review the PR, loss diagrams, monthly results, and the report. If you keep this order in mind, the items in the manual will begin to make practical sense.

For practitioners, what matters is not just operating quickly. Rather, it is important to document the rationale behind settings, make them comparable later, and ensure they are understandable to other team members. Solar power projects see conditions change as they progress through stages—initial study, proposal, detailed design, construction, and operation. If you make it clear each time which variant corresponds to which conditions, you can reduce rework.

The greatest value of applying the PVSyst manual in practice is that it allows you to connect simulation results to design decisions. Rather than simply producing energy yield figures, you become able to determine why those results occurred, which conditions should be revised to improve them, and which risks should be shared with stakeholders. This enhances the persuasiveness of proposals, the efficiency of internal reviews, and the clarity of explanations to clients.

Those who are about to start using PVSyst should begin by reading the manual with eight key points in mind. Even those already using it would do well to review past project files and verify that the meteorological data, loss conditions, shading settings, variant management, and report saving can be explained. The PVSyst manual can be used not only to learn how to operate the software but also as a standard for handling photovoltaic simulations at professional quality.