【How to Generate PVSyst Reports | 5 Items to Check Before Submission】

Table of Contents

• What to understand first about PVSyst report output

• Basic workflow for generating reports in PVSyst

• Items to check before submission 1: Project information and design conditions

• Items to check before submission 2: Meteorological data and site conditions

• Items to check before submission 3: How to read energy production and PR

• Items to check before submission 4: Consistency of the loss diagram and various losses

• Items to check before submission 5: Ease of explaining the overall report

• Common mistakes in report output and how to prevent them

• Practical approach to report management for day-to-day use

• Summary: Verify PVSyst reports together with on-site conditions

What to Understand First About PVSyst's Report Output

The PVSyst report is a summary document for explaining simulation results to third parties. It organizes the settings configured on the screen and the calculation results, allowing verification of energy production, losses, system configuration, meteorological conditions, monthly data, and so on. What is important for practitioners is not merely generating the report, but ensuring that the produced content is in a state that can be explained to the intended recipient.

People using PVSyst for the first time tend to assume the task is complete once they run a simulation and save the report. However, in reality, the figures in the report strongly depend on the input conditions. Slight changes in assumptions—installation location, azimuth, tilt angle, number of modules, PCS capacity, string configuration, wiring losses, temperature conditions, shading effects, assumed degradation and soiling, etc.—can alter the annual energy yield and PR. Therefore, before submission you need to check not only whether the results look good or bad, but also whether the conditions that produced those results are reasonable.

The report is also used as an internal review document, but as the project progresses the number of stakeholders increases. Design personnel, sales personnel, construction personnel, maintenance personnel, landowners, the client, and those responsible for investment decisions—all have different points of interest depending on who reads it. Design personnel emphasize the breakdown of losses and the equipment configuration; sales personnel emphasize parts related to annual energy production and expected revenue; construction personnel are concerned with layout and consistency with on-site conditions. In other words, a PVSyst report is not merely a set of calculation results, but a common document for stakeholders to discuss matters on the same assumptions.

Also, because PVSyst reports contain a lot of information, those unfamiliar with them are more likely to be unsure where to look. Reading every item in detail is important, but for pre-submission checks it is crucial to set priorities. First, verify that the project information and design conditions are correct, then check the meteorological data and site conditions. Next, review the energy generation, PR, loss diagram, and monthly trends, and finally confirm that the report is in a state that can be easily presented and explained as submission material. Reviewing in this order makes it easier to perform a well-founded check of the report rather than being led only by the numbers.

Basic workflow for generating reports in PVSyst

The process of generating a report in PVSyst basically follows the sequence of setting the simulation conditions, running the calculation, and generating the report from the results screen. In practice, you first create a project, configure the site and meteorological data, and enter the system configuration and loss conditions. After that, you run the simulation, check the annual energy production, PR, loss diagram, and monthly values on the results screen, and then output the report for submission.

Before generating the report, you should always check that the simulation has been run with the latest conditions. In design studies it is common to change the number of modules, adjust PCS capacity, or modify the azimuth and tilt angles. Even if you believe you changed the conditions on screen, if you have not recalculated after making those changes, the results reflected in the report may still be based on the old conditions. Before submitting, it is important to consciously verify that the conditions you last changed match the report results.

When outputting a report, it is necessary to make clear which simulation case the report corresponds to. When multiple design proposals have been created, similarly named cases may be listed, making it difficult to tell which one is the final version. For example, if proposals with different azimuths, different overloading rates, cases that account for shadow effects, and cases with conservative loss conditions are mixed together, there is a risk of accidentally submitting a report intended only for interim review. Before generating the report, confirm the case name, last updated date and time, and the main conditions, and clearly identify which case is to be treated as the final submission.

Regarding the output format, it is common to save it as an electronic document that is easy for the recipient to view. The important point here is not only to create a visually tidy document. It is essential to store it in a form that makes the project name, case name, creation date, design conditions, and main input values identifiable so that the same conditions can be reproduced later. If you save only the report by itself, it will be difficult to verify later when asked, "Under what conditions were these numbers calculated?" Managing the simulation data itself, the output report, supplementary materials, and field survey records as a single set of documents makes explanations and reexaminations smoother.

Pre-submission Checklist 1: Project Information and Design Conditions

Before submission, the first items to check are the project information and the design conditions. If there are errors here, no matter how carefully you review the figures for power generation or losses, the overall credibility of the report will be diminished. In particular, the project name, site name, system capacity, number of modules, PCS capacity, azimuth, tilt angle, and mounting method are the basic information the recipient will check first. Confirm that this information matches the actual design drawings and the estimate conditions.

Project names and case names are surprisingly easy to overlook. During the study phase, projects are often created with provisional names, and those names can end up remaining unchanged in reports. That may not be a major problem if the review is only internal, but when materials are to be submitted externally, the project name and study conditions need to be clearly organized. If you use names that convey the case’s position—such as final plan, comparative plan, impact-considered plan, or provisional plan—it will be less confusing when reviewing the documents later.

Next, what I want to check is the system capacity. In solar PV simulations, module capacity, PCS capacity, and the ratio between the DC side and the AC side affect energy production and losses. If you judge solely by the DC-side capacity, you may overlook the impact of output curtailment or clipping caused by PCS constraints. Conversely, if you only look at PCS capacity, you cannot verify consistency with the actual module configuration. In the report, confirm that the overall system capacity matches the design intent and be prepared to explain the approach for the DC side and the AC side as needed.

Azimuth and tilt angles are also important. For roof-mounted installations, azimuth and tilt are set to match the roof shape, and for ground-mounted installations they are set according to the racking design. A small difference in angle does not necessarily cause a large change in annual energy yield, but when preparing comparison scenarios or considering orientations other than south-facing, it is important to be able to explain the differences in conditions. In particular, east–west layouts, low-tilt configurations, and terrain-adaptive layouts will yield results different from the simple south-facing optimal condition. Before submitting the report, confirm that the actual layout plan corresponds to the settings in PVSyst.

Also, it is necessary to verify that the specification values for the modules and PCS have been selected correctly. In practice, generic data with similar performance are used during initial studies and later replaced with the formal specifications. If this replacement is forgotten, provisional conditions may remain in the final report. Before submission, rather than emphasizing the model name itself, it is important to confirm that conditions affecting the simulation results—such as capacity, efficiency, temperature characteristics, input range, and number of units—are reasonable.

Items to check before submission 2: Meteorological data and site conditions

The next items to check in a PVSyst report are the meteorological data and site conditions. Power generation simulations are heavily influenced by meteorological conditions such as solar irradiation, ambient temperature, and wind speed. Even with the same installed capacity, annual energy production will change if the site or meteorological data differ. Therefore, before looking at the report’s energy output, you should first confirm which site conditions were used for the calculations.

For site conditions, check whether latitude, longitude, elevation, time zone, and region name match the actual planned site. When substituting data from a nearby location in particular, it is important to understand the distance to the planned site and any differences in terrain. Even if a location is close numerically, solar radiation and temperature trends can differ in mountainous areas, coastal areas, basins, snowy regions, or areas prone to fog. Be prepared to explain the reasons for selecting the meteorological data if asked "why did you use this weather data" when submitting the report.

Also verify the type of meteorological data. The implications of the results vary depending on whether you are using mean annual data, observation data for a specific period, or data imported from external sources. Data meant to show average long-term trends and data that closely reflect the actual measurements of a particular year serve different purposes for evaluating power generation. For simulations used in business planning, you should select conditions that are reasonable as long-term trends rather than basing them solely on extremely good or bad years.

Regarding solar irradiance, the treatment of horizontal plane irradiance, tilted plane irradiance, direct components, and diffuse components affects the energy yield. In PVSyst, the irradiance incident on the installation surface is calculated from the input meteorological data, and after accounting for various losses the final energy yield is determined. Therefore, rather than looking only at the energy yield in the report, it is important to check whether the irradiance conditions are not excessively high or low. If there are values that appear anomalous compared with past similar projects or typical regional trends, review the selection of meteorological data and the import conditions.

Temperature conditions should not be overlooked. In photovoltaic systems, module temperature tends to rise and cause output to decrease. Therefore, in hot regions or installations with poor ventilation, temperature losses will affect power generation. If a report shows large temperature losses, check both the meteorological conditions and the installation conditions to confirm whether the results are reasonable. Conversely, if temperature losses are too small, it may also be advisable to verify that the input conditions match the actual situation.

Item 3 to Check Before Submission: How to Read Energy Production and PR

The core of the report is annual energy production and PR. Annual energy production is an important indicator that shows how much electrical energy the facility is expected to generate over the course of a year. PR, on the other hand, is an indicator for assessing how efficiently the entire system is generating power relative to solar irradiance conditions and system capacity. In practice, it is important not to look only at annual energy production but to verify it in combination with PR and the breakdown of losses.

When reviewing annual power generation, first confirm the units and the scope of measurement. Interpretation changes depending on whether the generation value is the DC-side figure, the value after conversion to AC, or a value near the grid interconnection point. If the data will be used in submitted documents, it is important to be able to explain at which point the energy amount is being measured. In particular, for materials related to electricity sales or project cash flow, you need to clarify the difference between simulated generation and the actual energy quantities that are subject to evaluation.

When evaluating PR, it is important not to judge solely by the numeric value. A high PR does not necessarily mean a good design, and a low PR does not necessarily mean a bad one. In high-temperature regions, on sites with substantial shading, or under conditions that conservatively anticipate snowfall or soiling, PR can be relatively low. Conversely, if loss conditions are not adequately included or shading effects are not considered, PR can appear higher than the actual situation. Before submission, check that the PR is consistent with the design conditions and loss assumptions.

Monthly power generation is also something you should check. The annual total alone does not reveal seasonal trends. You need to confirm whether generation increases in summer, falls in winter due to shading or insufficient solar irradiance, and how much it decreases during the rainy season or snowy periods. If the monthly variations align with regional characteristics and installation conditions, it becomes easier to explain in the report. Conversely, if an extreme value appears in a particular month, it provides an opportunity to check for any inconsistencies in the weather data, shading settings, or loss settings.

When submitting comparative proposals, it is important to clearly state the reasons for differences in power generation. For example, determine whether the change in output was caused by differences in azimuth angle, differences in tilt angle, differences in PCS capacity, or because the impact of shading was taken into account. Simply indicating that “Plan 1 has higher generation” is insufficient for decision-making. Being able to explain which differences in conditions lead to which differences in outcomes will make the report more persuasive.

Item 4 to check before submission: Consistency between the loss diagram and various losses

In PVSyst reports, checking the loss diagram is extremely important. The loss diagram shows at which stages and what kinds of losses occur during the process in which solar irradiation energy is converted into the final electricity output. Because it allows you to identify causes that are not visible from the generation figures alone, it is an item you should always check before submission.

Losses include various factors such as reflection loss, temperature loss, mismatch loss, wiring loss, conversion loss, shading loss, soiling loss, and losses related to output limitation. The losses that have the greatest impact vary by project. In ground-mounted projects with few surrounding obstacles the impact of shading is small, while for rooftop installations or on undulating terrain shading can be significant. In high-temperature regions temperature loss tends to be larger, and in designs with long wiring distances it is important to check wiring loss.

When looking at a loss diagram, check whether each loss is too large or too small. If there is a loss that is too large, you need to be able to explain its cause. For example, if temperature losses are large, check whether ambient temperature conditions or the installation method are having an effect. If shading losses are large, review nearby obstacles, topography, row spacing, orientation, the sun altitude in winter, and so on. If wiring losses are large, check wiring length, cross-sectional area, voltage conditions, and system configuration.

Conversely, be cautious when losses are too small. In practice, omitting losses can cause power generation to appear overestimated. Typical cases include not accounting for shading effects, not assuming soiling, simplifying wiring conditions, or leaving equipment loss parameters at their default values. If the results in a report look too good, rather than simply celebrating, confirm that losses appropriate to the actual conditions are being reflected.

Loss diagrams are also useful for explanations to the recipient. Even if power generation is lower than expected, a loss diagram can help clarify which factors are influencing performance. For example, if shading losses are large, there may be room to reconsider the layout, and if limitations on the PCS side are significant, revising the capacity design becomes an option. Temperature losses are related to the installation method and ventilation conditions, while soiling losses are related to maintenance planning. In this way, a loss diagram is not merely a presentation of results but an entry point for considering improvement measures.

Item 5 to Check Before Submission: Ease of Explaining the Entire Report

Finally, what I want to confirm is how easy the overall report is to explain. Because PVSyst reports contain a large amount of information, they are useful to those with specialist knowledge, but not all stakeholders will necessarily understand them to the same depth. Before submission, anticipate which items the recipients of the report will prioritize and prepare supplementary explanations as necessary.

To make a report easy to explain, it is important to first organize the key conclusions. Be sure to grasp the annual energy production, PR, major losses, monthly trends, differences from alternative proposals, and any assumptions that should be noted. Rather than opening the report and immediately reading out the numbers, prepare to explain the overall picture of the results in a form such as, "Under this proposal the annual energy production is roughly this amount, the main loss factors are temperature and conversion, and the impact of shading is limited," which will make meetings go more smoothly.

Also, prepare explanations of the technical terms included in the report. Terms such as PR, losses, irradiance on tilted surfaces, DC capacity, AC capacity, temperature losses, and mismatch losses may be familiar to solar power system designers, but they are not necessarily intuitive to all stakeholders. When using these materials for submission, it is a good idea to supplement them with separate appendices or in-text explanations as needed. It is important not just to list technical terms, but to explain how they relate to decision-making.

When using reports as comparison materials, clarify which conditions were changed for the comparison. When multiple proposal reports are placed side by side, attention tends to focus only on differences in energy generation and PR. However, if the comparison conditions are not aligned, the meaning of numerical differences is unclear. For example, if one report accounts for shading and the other does not, the difference in generation is due to differences in input conditions rather than the superiority of a design proposal. Before submission, verify that the reports used for comparison have consistent meteorological data, loss conditions, equipment conditions, and output conditions.

File names and storage methods also affect how easy it is to explain things. It is not uncommon for revised versions to be produced after a report has been submitted. In such cases, if it is unclear which document is the latest or which conditions the report refers to, confusion can arise among the relevant parties. Make file names so the content is clear later on—for example, by including the project name, case name, creation date, and key conditions. When sharing within the company, it is also reassuring to manage not only the report but the original simulation data and any supplementary notes together.

Common Mistakes in Report Output and How to Prevent Them

One common mistake in PVSyst report output is producing reports based on outdated conditions. During design studies, conditions are frequently changed. If you forget to recalculate after changes such as adjusting the number of modules, changing PCS capacity, adding shading conditions, or modifying loss rates, the report results will not match the latest conditions. To prevent this, check the simulation case name and the key conditions just before generating the report, and recalculate if necessary before producing the report.

Another common mistake is leaving provisional conditions in place. In initial studies, temporary site locations, provisional equipment data, standard loss rates, and approximate layout conditions may be used. While this is acceptable during the study phase, before using the documents as submission materials it is necessary to check that no provisional conditions remain. In particular, equipment specifications, installation angles, meteorological data, shading conditions, soiling conditions, and wiring conditions should be reviewed. If provisional conditions are being used, either state this clearly when submitting the report or update them to final conditions before submission.

Putting too much emphasis on generation output alone can also lead to failure. Generation output is an important indicator, but showing only the numbers does not convey why those values occurred. By checking PR, loss diagrams, monthly generation figures, and weather conditions together, the rationale behind the results becomes clear. When you receive questions from the recipient of your submission, it is important to be able to explain not only the generation output but also the breakdown of losses and the design conditions.

Sometimes comparison scenarios are submitted without their conditions being aligned. When placing multiple reports side by side, if even one condition differs, a straightforward comparison becomes impossible. If the purpose of the comparison is to examine differences in azimuth, all other conditions should be matched as closely as possible. If you are comparing PCS capacity, the meteorological data and loss conditions should be the same. When conditions are mixed, the reasons for differences in power generation become unclear, making the results difficult to use as a basis for decision-making.

During the final check before submission, it can be effective to have another person review the work. It is often difficult to notice input errors and oversights in reports you prepare yourself. A third party review can catch mistakes such as incorrect project names, misread units, inconsistent conditions, or insufficient explanations. Especially for materials to be submitted externally, having someone other than the author verify them makes it easier to prevent rework and a decline in credibility.

Practical, Easy-to-Use Approaches to Report Management

PVSyst reports should not be treated as a one-time output; it is important to manage them as part of the project's review history. In planning a solar power plant, simulations may be run at multiple stages—initial assessment, preliminary design, detailed design, pre-construction verification, and change reviews. If you generate a report each time, the number of documents increases and it becomes difficult to tell which one is the latest.

To make management in practice easier, clarify the positioning of the report. Distinguish whether it is for preliminary study, internal review, submission, or comparison. In addition, when you make major changes to design conditions, it is useful to leave a note that indicates what changed. For example, recording changes that affect the results—such as layout changes, PCS capacity changes, additions to shading conditions, changes to meteorological data, and corrections to loss rates—makes it easier to trace the reasons for numerical differences later.

It is also important to manage on-site information alongside the report. The settings in PVSyst are a simulation model, but actual power plants are influenced by local topography, surrounding obstructions, site development plans, racking layout, roads, drainage, vegetation, snowfall, maintenance access routes, and so on. Cross-checking with site conditions is indispensable to determine whether the figures in the report are reasonable. If the desk-based design conditions differ from the actual site, the accuracy and explanatory power of the simulation results will decrease.

In particular, the effects of shading and terrain conditions cannot always be fully assessed from a report alone. Surrounding buildings, trees, slopes, utility poles, fences, and adjacent structures can be difficult to identify without on-site inspection. For ground-mounted installations, the post-development ground elevation and height differences between racking rows can also affect power generation. By cross-checking site photographs, survey data, layout drawings, and topographic information before and after report generation, you can produce materials that better match practical requirements.

In report management, it is important to retain not only the final version but also the records of the review process. You may later need to explain why a particular design proposal was adopted. In such cases, having draft reports and comparison materials makes it easier to explain the rationale behind the decision. However, because unnecessary provisional reports mixed in can cause confusion, it is important to organize storage locations and naming rules and to clearly separate the final submission from materials intended for review.

Summary: Verify PVSyst reports together with on-site conditions

PVSyst report output is an important step for organizing simulation results into submission materials. The basic workflow is condition setting, simulation execution, result review, and report output, but what matters in practice is whether the generated report can be explained. Before submission, check the project information and design conditions, the meteorological data and site conditions, the energy production and PR, the loss diagram, and how easily the entire report can be explained.

Especially, rather than looking only at the figures for power generation and PR, it is important to verify that the underlying assumptions and conditions are reasonable. If system capacity, azimuth, tilt angle, equipment configuration, loss conditions, meteorological data, and shading effects do not match the actual plan, a report may look well formatted but its credibility as a submission will not improve. Conversely, if the relationship between conditions and results is well organized, you can give a convincing explanation in internal reviews and to the client.

Also, a PVSyst report is the result of a desk-based study and only gains practical value when cross-checked with on-site conditions. In planning a solar power plant, site topography, nearby obstructions, land development status, racking layout, and maintenance access routes affect energy production and losses. To make the figures presented in the report a more reliable basis for decision-making, it is effective to verify them by linking them with on-site coordinates, elevation, photographs, point clouds, and layout information.

Therefore, when reviewing a report created with PVSyst before submission, it is reassuring to organize the information from on-site surveys and surveying as well. LRTK, as an iPhone-mounted GNSS high-precision positioning device, makes it easy to utilize the location information and records obtained in the field for design and verification work. By linking the simulation conditions with the actual on-site conditions, PVSyst reports become more than mere calculation sheets and are easier to use as field-based explanatory materials.