PVSyst Report Creation Manual | 6 Points to Check

After estimating the power generation of a photovoltaic system with PVSyst, what project personnel often find confusing is how to compile the report. Simulation results are predictions based on the input conditions and are not necessarily suitable to be used as submission documents or explanatory materials as-is. If you share them without checking the consistency of the design conditions, meteorological data, equipment conditions, loss settings, generation results, and notes, revisions may be requested during internal review, client briefings, feasibility assessments, or pre-construction reviews.

This article organizes six points that practitioners should check when preparing PVSyst reports, presented in a way that is easy to understand even for first-time users. It explains not just how to output reports, but focuses on the approach to arranging materials so they are less likely to be misinterpreted by readers. Note that this article uses the notation PVSyst to match the form used in searches and practice, but please confirm the software’s official name and your organization’s internal naming rules in your documents.

Table of Contents

• Objectives to establish first when preparing a PVSyst report

• Checkpoint 1: Ensure project conditions and basic information are consistent

• Checkpoint 2: Confirm assumptions for meteorological data and site conditions

• Checkpoint 3: Confirm the specifications of modules and power conditioners

• Checkpoint 4: Present loss settings and correction conditions in a way that is clear to the reader

• Checkpoint 5: Organize how to interpret energy generation, performance ratio, and monthly results

• Checkpoint 6: Pre-submission checks and incorporation into explanatory materials

• Summary for applying PVSyst reports in practice

Objectives to grasp first when creating a PVSyst report

When creating a PVSyst report, the first thing to be conscious of is clarifying who the document is for and what decision you want them to make. Simulation results for solar power generation are not something only the design staff review. Depending on the project, people in multiple roles—sales staff, construction managers, electrical designers, landowners, those responsible for investment decisions, maintenance managers, and so on—may all look at the same document. Therefore, a report that simply lists numbers can be interpreted differently by different readers.

What requires special attention is treating PVSyst’s output results as “confirmed annual energy production.” Simulations are estimates based on the input conditions. Actual energy generation is influenced by weather conditions, construction quality, grid-side constraints, soiling, shading, equipment outages, maintenance status, and whether output curtailment is applied. Therefore, the report should be structured to clearly convey that these are “assumed results when estimated under these conditions” and are not actual performance figures or guaranteed values.

There are three main purposes for preparing the report. The first is to verify the validity of the design conditions. This involves checking whether equipment capacity, installation angle, orientation, equipment configuration, number of arrays, string configuration, and so on match the project’s planned specifications. The second is to make it possible to explain the breakdown of generation and losses. Not only the annual energy production, but also which losses are large, how seasonal variations appear, and whether the performance ratio is unreasonably high or low for the given conditions are checked. The third is to prepare materials that can be used to build consensus both inside and outside the company. If the reader can trace the connection between the input conditions and the results, it will be easier to make comparisons if the conditions are changed later.

A PVSyst report is not necessarily complete at the time it is generated. In practice, preparing the report involves checking the output results, supplementing the assumptions as needed, transcribing them into explanatory materials, and adding project-specific points to note. Especially when comparing multiple proposals, if conditions are not aligned under the same rules, it becomes difficult to determine whether differences in energy production are due to design differences or to differences in input conditions.

Also, readers of the report are not necessarily familiar with how to operate PVSyst. Therefore, rather than simply listing technical item names, it is important to summarize with attention to which conditions affect energy production and which figures should be checked closely. The person preparing the report serves not only as the software operator but also as the presenter who communicates the simulation conditions to the reader.

Checkpoint 1: Gather project conditions and basic information

The first thing to check in a PVSyst report is the project conditions and basic information. If these are misaligned, no matter how carefully the subsequent energy production results and loss assessments are organized, the credibility of the document will be reduced. Verify that basic information—project name, site name, system capacity, proposal name, creation date, author, purpose of the simulation, etc.—matches the names used in project management.

In practice, it is common to produce multiple design proposals for the same project. For example, proposals with different installation angles, different equipment capacities, consideration of shadow effects, or versions after layout changes. When report names or simulation names are ambiguous, it becomes unclear which document is the latest. Rather than relying solely on file names, make the analysis conditions clear within the report text so that people checking it later are less likely to be confused.

Care should be taken in how equipment capacity is indicated. In solar power generation, the DC capacity on the photovoltaic module side and the AC capacity seen at the power conditioner or at the point of receipt can differ. To prevent readers of a report from being confused about which capacity they are looking at, it is important to clarify the DC-side capacity, the AC-side capacity, the DC/AC ratio, and the concept of over-sizing. In particular, when comparing generation per unit of installed capacity, the evaluation changes depending on which capacity is used as the denominator.

Installation orientation and tilt angle are also important basic information. Orientation and angles affect annual energy generation and seasonal generation trends. Whether the installation is close to south-facing or tilted toward the east or west, and whether the tilt angle is low or high, will change the balance of generation between morning and afternoon and the amount of generation in winter. Check that the orientation and angles in the report match the design drawings and the layout plan. If the azimuth reference or notation rules differ between documents, provide clarifications so the reader will not be misled.

Furthermore, you need to clarify the scope of the simulation. Whether you are estimating the entire power plant as a whole, only a specific section, or extrapolating from a representative array to the whole will change how the report should be used. If some conditions have been simplified, it is safer to explain those assumptions within the documentation.

When verifying basic information, check not only the accuracy of the figures but also whether the notation could cause readers to misunderstand. For example, small inconsistencies—such as mixed numbers of decimal places for capacities within documents for the same project, mixed date formats, or old conditions remaining in proposal names—undermine the credibility of the entire document. Before submission, it is important to cross-check the simulation conditions against the project management sheet, drawings, equipment lists, and internal review notes to ensure there are no discrepancies in the basic conditions.

Checkpoint 2: Confirm assumptions regarding meteorological data and site conditions

In PVSyst reports, checking the meteorological data and site conditions is indispensable. Solar power output varies with solar irradiance, temperature, wind conditions, topography, and the surrounding environment. Because irradiance in particular tends to directly affect annual energy production, it is necessary to confirm which location or data source the meteorological data comes from and whether there are any significant differences in distance or elevation from the project site.

In practice, meteorological data are not necessarily long-term measured values taken at the site itself. Data from nearby stations, satellite-estimated data, representative-year data, or conditions derived by processing multi-year data may be used. Therefore, reports verify whether the meteorological conditions used are appropriate to represent the site. In coastal areas, mountainous regions, snow-prone areas, regions prone to fog, or areas with high surrounding terrain, the average solar radiation from nearby stations alone may not adequately reflect local characteristics.

Temperature conditions are also important. Solar photovoltaic modules generally tend to have reduced power output as cell temperature rises. Therefore, even with the same solar irradiance, energy production and how losses manifest will differ between regions with different temperature and wind conditions. When reviewing reports, check not only the irradiance but also the extent to which temperature effects are included. In hot regions, expect a reduction in output during summer; in cold regions, consider factors such as snow cover and voltage conditions at low temperatures — you need a perspective that reads region-specific characteristics.

Regarding site conditions, check how surrounding shadows are handled. Shadows from buildings, trees, mountains, utility poles, racking rows, adjacent equipment, and the like affect power generation. The meaning of the report can change significantly depending on how far the shadow impacts are modeled. Confirm whether shadows are being evaluated in a simplified way, whether nearby shadows are entered in detail, or whether distant terrain shading is being considered. If shadows are not sufficiently accounted for, it is safer to treat that report not as a final judgment but as an initial study or a conditional estimate.

Also, the site conditions that need to be checked differ between ground-mounted and roof-mounted installations. For ground-mounted installations, terrain undulation, row spacing, post-construction ground elevation, surrounding vegetation, and shadows from fences and equipment are important. For roof-mounted installations, roof pitch, orientation, surrounding buildings, rooftop equipment, handrails, and lightning protection equipment shadows have an impact. Rather than looking only at the PVSyst report results, compare them with on-site photos, layout drawings, plan views, and sectional drawings to confirm that the entered site conditions do not significantly deviate from the actual plan.

Meteorological data and site conditions are the assumptions underlying power generation estimates. If there is uncertainty here, it is desirable to include explanations in the report such as "These estimates are based on neighboring or estimated conditions" and "They may be revised after an on-site survey." Avoid overly definitive expressions; clearly stating that the estimates are conditional will help prevent problems in later stages.

Checkpoint 3: Confirm the conditions of the modules and power conditioners

A major factor that determines the reliability of a PVSyst report is the conditions of the PV modules and power conditioners. If the equipment conditions deviate from the project plan, the assessments of annual energy production, losses, performance ratio, and output limitations will change. When preparing the report, it is important to confirm not only the equipment names themselves but also that the electrical specifications entered match the plan.

First, you should check the capacity, number of modules, and string configuration of the photovoltaic modules. Verify that the module's nominal maximum power, the number of modules in series, the number in parallel, and the number of arrays match the design drawings and the single-line wiring diagrams. Even a difference of one module can change the total capacity and the voltage range. Especially for projects with multiple roof surfaces or multiple orientations, the number of modules and tilt angles per surface tend to be mixed, so it is necessary to reconcile the configuration in the report with the design drawings.

Next, check the rated capacity on the power conditioner side, the number of input circuits, how MPPT is handled, the voltage range, and how output limiting is handled. If the AC-side capacity is smaller than the DC-side capacity, output may be capped during periods of strong solar irradiance. This can be adopted as a design approach, but if losses due to output limiting appear large in the report, you should be prepared to explain that design policy.

Checking the voltage range under different temperature conditions is also important. In general, module voltage tends to increase at low temperatures and decrease at high temperatures. If the number of modules in series is not appropriate, the system may approach the input upper limit at low temperatures or fall outside the operating range at high temperatures. In PVSyst reports, you should not only look at energy yield but also assess whether the combination of equipment is electrically valid. Final safety checks and equipment selection should be carried out in conjunction with manufacturer datasheets, design standards, and confirmation by the electrical designer.

Also, pay attention to how long-term degradation is handled. Whether the figures show first-year generation or assume a certain number of years have passed, and how degradation rates are treated, will change how readers interpret them. When using this for project feasibility assessments or long-term financial projections, you need to consider long-term output decline in addition to single-year simulation results. Clarifying which point in time the numbers in the PVSyst report refer to will prevent discrepancies in explanations.

When checking equipment conditions, it is important to organize the information so the reader can follow the items needed to make a judgment, rather than listing overly detailed technical terms. For example, explaining in a single, cohesive section the total number of modules, DC capacity, AC capacity, configuration per installation surface, number of power conditioners, and the main loss factors will improve understanding of the report. Equipment conditions form the foundation for power generation, so they should be reviewed carefully before submission.

Checkpoint 4: Make the loss settings and correction conditions clear to the reader

In PVSyst reports, loss settings and correction conditions are what practitioners particularly find difficult to explain. In a generation simulation, the energy theoretically obtainable from solar irradiance does not directly become the final generated energy. Various factors cause losses—temperature, shading, soiling, wiring, mismatch, conversion efficiency, power curtailment, shutdowns, reflection, and degradation over time. In the report, it is necessary to check how these losses are configured and how they are reflected in the results.

The first thing to check is whether the losses are set within a range that can be explained by the project conditions. If losses are set low, the estimated power generation will look high, but if it diverges from actual operation, the gap with actual results may become large later. Conversely, if losses are set excessively high, the project’s viability will be estimated more strictly than necessary. What’s important is to base assumptions on the project’s location, construction conditions, maintenance policy, and surrounding environment.

Soiling losses vary depending on the region and installation environment. In locations with a lot of dust, near agricultural land, in places prone to bird activity, or in regions with low rainfall, the impact of soiling can be greater. Conversely, when regular inspection and cleaning are assumed, those maintenance policies should be taken into account when defining the settings. However, if the report asserts the presence or frequency of cleaning, confirm that this matches the actual maintenance plan.

Wiring losses and conversion losses are also items that are frequently checked in practice. In projects with long wiring distances, or where the distance from the combiner box to the receiving equipment is large, wiring losses affect energy production. At the estimation stage, standard values may be used, but as the design progresses it is desirable to review them according to the wiring route and voltage conditions. Regarding conversion losses, the operating range of the power conditioner and its efficiency under partial load also affect the results.

Shading losses have a major impact on the interpretation of results. Even if shading losses reported in a report appear small, if shading was not entered in detail to begin with, that figure may not adequately reflect the on-site impact. Conversely, when a detailed shading analysis is included, being able to explain which times of year and which times of day shading effects are likely to occur makes it easier to consider layout changes and row spacing. It is important to check shading not only in the reported numbers but also in the way it was entered and the modeling assumptions.

What matters in loss settings is not just showing the numbers, but presenting them so the underlying assumptions can be explained. Readers are often more interested in "why that value was adopted," "how conservative it is," and "how much the results would change if it were altered" than in the loss rate itself. In internal documents, conditions are sometimes divided and compared as standard conditions, conservative conditions, and improvement proposals. In such cases, manage the loss settings consistently across the options and make it clear which items were changed.

When using a PVSyst report as submission material, loss settings are a part that often requires explanation and justification. Therefore, rather than simply entering the configured values and leaving it at that, it is important to document the rationale, assumptions, and any unresolved items. Explicitly state conditions that remain unresolved and note that they will be reviewed during subsequent design development or on-site surveys, as this helps avoid excessive expectations or misunderstandings.

Checkpoint 5: Organize how to interpret power generation, performance ratio, and monthly results

In a PVSyst report, the most attention-grabbing figure is the annual energy production. However, it is not reliable to judge a system based solely on annual energy production. When preparing the report, we review the annual energy production, monthly energy production, energy production per unit of installed capacity, the performance ratio, and the breakdown of losses together to check for any anomalies in the results.

Annual energy generation is a metric often used to assess the overall profitability of a project and for comparative evaluation. However, even plants with the same capacity can produce different amounts of energy depending on location, orientation, tilt, shading, temperature, and loss assumptions. Therefore, to judge whether annual generation is high or low, comparisons must be made using the same assumptions. Even when comparing with past projects or neighboring projects, a simple comparison is not valid if the meteorological data or loss assumptions differ.

Monthly generation helps validate a report. Due to solar irradiance conditions and the sun’s altitude, monthly generation experiences seasonal variations. In some regions it is higher in summer, while in others seasonal patterns may change because of rising temperatures, the rainy season, snowfall, or shading. Checking the monthly results makes it easier to detect features such as a particular month being unusually low, shading losses that are seasonally large, or output curtailment concentrated in specific periods.

The performance ratio is one of the representative indicators for assessing how effectively a system generates electricity relative to incident solar irradiance and system capacity. However, the performance ratio is not a simple metric where higher is always better. Because it varies depending on the set conditions, if it is excessively high, check whether loss assumptions are underestimated and whether shading and soiling have been adequately accounted for. Conversely, if it is too low, check for problems with shading, temperature, wiring, output limitation, and equipment configuration. It is important to interpret the performance ratio not as a standalone number but together with the assumptions and the breakdown of losses.

Checking the units is essential when reviewing generation results. Mixing annual generation, monthly generation, and generation per unit of capacity can easily lead readers to misunderstand. Be particularly careful when transferring figures into internal documents or proposals, as unit omissions or scale errors for units such as kWh, MWh, kWh/kWp, kW, kWp, and kWac are common. When rounding numbers, if you do not standardize the rounding method, totals and breakdowns can appear inconsistent.

Also, when comparing multiple options, make the comparison criteria clear. For example, if you are comparing options that change the installation angle, you should keep the meteorological data, number of modules, loss settings, and shading conditions as identical as possible. If you change equipment capacity and loss settings at the same time, it becomes difficult to determine which factor is causing the difference in generation. When creating a comparison report, it is important to minimize the number of variables changed at once so that the differences in results are easier to explain.

When the figures in a report look suspicious, don't just adjust the results—go back and check the input conditions. If energy production is higher than expected, check for missing shading inputs, insufficient loss settings, capacity mix-ups, azimuth input errors, and similar issues. If energy production is too low, check the tilt angle, azimuth, meteorological site, output limits, string configuration, and shading conditions. A PVSyst report is not only a document for reading results but also a tool for working backwards to verify the validity of the input conditions.

Checkpoint 6: Pre-submission Check and Incorporation into Presentation Materials

Before submitting a PVSyst report, you should not simply attach the output as-is; you need to organize it into a form that makes it easy for the reader to evaluate. In practice, reports generated by PVSyst are often used as the basis for internal briefing materials, proposal documents, design review documents, and project feasibility documents. Because transcription errors and insufficient explanations of the conditions can easily occur, it is reassuring to establish a pre-submission check procedure.

The first thing to check is whether the report is the latest version. If you rerun simulations many times, reports based on old conditions can remain. Even if the file name includes a date or proposal name, the contents may still be outdated. Before submitting, check the creation date, proposal name, equipment capacity, and installation conditions in the report to ensure they match the current plan. If necessary, keeping version numbers or an update history makes it easier to trace the background later.

Next, verify consistency among the documents. Check whether the figures in the PVSyst report, the layout plan, the equipment list, the single-line diagram, the power generation summary table, and the business feasibility calculation sheet match. In particular, DC capacity, AC capacity, number of modules, number of power conditioner units, annual energy generation, and generation per unit of installed capacity are items that tend to differ between documents. If you correct only one document and forget to update the others, readers will not be able to tell which is correct.

When preparing explanatory materials, you do not need to cram every item into them. What is important for the reader are the assumptions behind the estimate, the main results, points to note, and the conditions that might be revised in the future. Attach the detailed PVSyst report as supporting documentation, and in the explanatory materials it is easier to handle if you organize and present the key points. However, if you summarize too much the assumptions become obscured, so retain enough information to make clear under which conditions the estimated energy generation was produced.

In terms of wording, it is also important not to be too definitive. For example, it is safer to avoid expressions such as "This will definitely be the annual power generation." Because actual power generation varies depending on weather and operating conditions, use phrasing that conveys meanings like "This is a calculation based on certain assumptions" and "This does not guarantee actual results." Be especially careful in materials intended for external audiences to ensure that projected values and guaranteed values are not confused.

We will also review the report’s notes and supplementary explanations. If there are unconfirmed conditions, simplified conditions, provisional conditions prior to on-site investigation, or conditions that may change in the future, they will be clearly stated in the document. This will make it easier for readers to determine which parts should be regarded as confirmed information and which should be treated as matters for future consideration. When the document is used externally, we will, as necessary, clarify the division of roles between this and other materials so that it is not confused with contract terms, warranty conditions, financial decisions, and the like.

During the pre-submission check, it is also useful to verify that readers other than technical specialists will not have major misunderstandings. Assumptions that are obvious to the design team can be difficult for sales or management personnel to grasp. If the document will be used as explanatory material, it is important to organize it so that not only the generation figures but also the meaning of the conditions is clear. A PVSyst report is a detailed technical document, yet in practice it also functions as explanatory material that supports decision-making.

Summary for Utilizing PVSyst Reports in Practice

In PVSyst report preparation, the important thing is not simply outputting the report, but correctly linking the calculation conditions and results and organizing the material so readers can easily make judgments. Reviewing the project conditions, meteorological data, site conditions, equipment configuration, loss settings, generation results, and pre-submission consistency checks as an integrated workflow will tend to increase the reliability of the documentation.

In practice, the annual energy production figure tends to attract attention first. However, that figure is the result of a cumulative set of input assumptions. If the meteorological data changes, the result changes; if the shading conditions change, the result changes; if the loss settings change, the result changes. That is why, in a PVSyst report, it is important not only to look at the magnitude of the numbers but to verify that the assumptions match the actual conditions of the project.

Also, the report is not just for its creator. It is referred to in various situations such as internal reviews, client briefings, design studies, construction planning, and maintenance planning. Making it clear, when reviewed later, under which conditions the estimates were calculated has great significance from a project management perspective. By carefully documenting the project name, date, capacity, specified conditions, and notes, it becomes easier to compare and explain results when conditions change.

Power generation simulations using PVSyst play an important role in the planning stage of solar power plants. However, simulation results are not definitive for actual site and operating conditions. Given that they are forecasts, it is necessary to use them while cross-checking against design conditions, construction conditions, and maintenance conditions.

When you are still inexperienced in report writing, simply checking the six points introduced here will make it easier to reduce returns and insufficient explanations. By reviewing in order whether the project information is correct, the meteorological data are appropriate, the equipment configuration is correct, you can explain the loss settings, there are no anomalies in the power generation results, and the submission materials are properly prepared, you will move closer to a report that can be used in practice.

In the design and construction management of photovoltaic power generation, it is important to handle, as an integrated set, not only simulation results but also on-site survey information, layout studies, pre- and post-construction inspections, and data related to operation and maintenance. When creating PVSyst reports, too, do not rely solely on the software results; organize the materials into explainable documentation by cross-checking drawings, site conditions, equipment specifications, construction conditions, and operational policies.