Introduction to the PVSyst Manual | 7 Steps from Initial Setup to Analysis

When using PVSyst (official notation: PVsyst) to estimate the power generation of a photovoltaic power plant, simply filling in the fields on the screen in order does not produce analysis results that are easy to explain in practice. Only when the meteorological data, azimuth, tilt angle, module conditions, loss settings, treatment of shading, and how to read the result reports are connected will you have material that can be used for design review, internal explanations, and client-facing documentation.

This article, aimed at practitioners searching for "PVSyst manual", organizes the process into seven steps from initial setup to reviewing analysis results. To help even first-time users grasp the overall picture, it explains not only the actions to perform, but also the reasoning to check when configuring settings and the cautionary points that often lead to differences in energy yield. Note that screen names and detailed operation procedures may vary depending on the version and your environment, so when entering data please also consult the official documentation and your company's internal rules.

Table of Contents

• Overall picture to grasp first in the PVSyst manual

• Set units, region, and basic conditions in the initial settings

• Set project information and site conditions

• Check meteorological data and solar irradiation conditions

• Enter the parameters for PV modules and power conversion equipment

• Organize layout, tilt, azimuth, and shading effects

• Check loss settings and run the analysis

• Read the analysis result report and connect it to areas for improvement

• Precautions for stable operation of PVSyst in practice

• Summary: Master PVSyst analysis by covering condition organization through result verification

The overall picture to grasp first in the PVSyst manual

PVSyst is a specialized analysis software used for the design studies, sizing, energy production simulation, and data analysis of photovoltaic (PV) systems. It is used in various situations, from preliminary estimates before design to comparing equipment configurations, checking loss factors, and preparing annual energy production forecasts. However, because there are many settings, first-time users often get confused about "where to start configuring" and "how rigorously to enter each value."

In practice, the important thing is to use PVSyst not simply as a power-generation calculation tool but as an analysis environment for organizing the conditions, clarifying assumptions, and verifying the validity of the results. Even for the same power plant, the annual energy yield will change if site conditions, meteorological data, tilt angle, azimuth, equipment specifications, loss rates, or the way shading is handled are different. Therefore, rather than looking only at the output numbers, it is necessary to check which conditions produced those results.

The basic workflow of PVSyst is to create a project, set the site, load the meteorological data, enter the configuration of the power generation equipment, adjust installation conditions and losses, run the simulation, and review the results. Although the interface is divided into multiple setting items, in practice it is easier to understand if you organize them in the order: "Location", "Irradiation", "Equipment", "Layout", "Losses", "Results".

Especially in the initial analysis, before nailing down detailed numerical values, it is important to first review all the input items at once. Knowing which items are mandatory, which are optional, and which conditions have a large effect on the results will make re-analysis later less confusing. Rather than merely memorizing procedural steps from a manual, understanding how each setting affects power generation will make you stronger at making practical adjustments and explanations.

Also, the PVSyst analysis results do not fully guarantee actual power generation. They are merely estimates based on the input conditions, and actual generation can be affected by year-to-year weather variability, installation quality, maintenance practices, equipment aging, changes in the surrounding environment, and other factors. Therefore, it is safer to treat the analysis results not as "definitive values" but as "conditional projections." When using them in internal documents or when explaining to customers, it is important to clearly state the input conditions and assumptions.

Configure units, region, and basic conditions during initial setup

When starting to use PVSyst, don’t jump straight into entering the power plant’s detailed data; first check the initial settings and your working environment. By standardizing units, displays, site conditions, and the approach to data storage, you make it easier to prevent input mistakes and misinterpretation of results in later stages. This is especially important when multiple people work on the same project: if units and naming rules aren’t consistent, it becomes difficult to compare analysis results later.

The first thing to check is the units being used. In photovoltaic analysis, multiple units appear for quantities such as power output, area, irradiation, temperature, and energy. If the units used in your usual internal or design documents differ from those displayed in PVSyst, misreading can occur when entering data or reviewing reports. In particular, annual energy production, specific yield, installed capacity, and loss rates are often transcribed into explanatory materials, so it is important to make a habit of confirming which units are being displayed each time.

Next, decide how to manage projects and files. In PVSyst you may create multiple scenarios for each project and compare tilt angles, equipment configurations, and loss conditions. Therefore, if file names or scenario names are ambiguous, it can be difficult to tell which analysis is the most recent. Preparing a naming convention that includes the project name, site name, analysis conditions, creation date, and person in charge makes it easier to understand the contents when reviewing them later.

In the initial setup, we also confirm the region to be analyzed and how meteorological data are handled. For solar power generation estimates, site conditions are extremely important. Even with the same system capacity, differences in solar irradiance and temperature will change the amount of power generated. Using meteorological conditions close to the target site, checking for any extreme differences in elevation or surrounding environment, and comparing multiple datasets as needed all help reduce variations in estimated generation.

Also, at the initial setup stage, it is important to clarify within the company what level of accuracy is required for the analysis. The required input precision will vary depending on whether the study is a preliminary estimate, a study close to detailed design, intended for proposal materials, or for post-construction comparison. In the preliminary stage it is realistic to capture the major trends under standard conditions, while in the detailed stage it is appropriate to verify equipment specifications and loss conditions more carefully.

The initial settings for PVSyst are not something you complete once and forget. If the type of project or internal procedures change, you may need to review and update the settings. In particular, when a new person takes over the analysis or when reusing conditions from past projects, it is important to verify that old settings or assumptions from previous versions are not being used unchanged.

Set project information and site conditions

To begin a detailed analysis in PVSyst, first create the project information and enter the site conditions. The information you set here affects later meteorological data, solar position, and energy production calculations, so it must be carefully verified at this initial stage. If the site conditions are incorrect, no matter how finely you adjust the equipment settings, the assumptions underlying the entire analysis will be skewed.

In the project information, organize items such as the project name, location, purpose of the analysis, and system type. In practice, you may compare multiple layout proposals on the same site or evaluate the same equipment while changing only the loss conditions. Therefore, it is useful to clearly separate the project name from the analysis-case name. For example, use the power plant or project title as the project name, and include expressions in each analysis case that indicate differences in tilt angle, azimuth, equipment configuration, and loss settings to make comparisons easier.

For site conditions, latitude, longitude, elevation, and time conditions are important. Latitude and longitude relate to solar position calculations and also affect solar incidence angles and shadow formation. Elevation serves as a basis for judging temperature conditions and the representativeness of meteorological data. These pieces of information should be verified using map data and design documents to ensure input values do not contain large errors. Even for rough assessments, it is safer to use location information as close to the site as possible rather than at the prefectural level.

When setting the site point, the key consideration is where to place the representative point of the site. In large solar power plants, elevation differences and surrounding conditions can vary within the site. In small installations this may not be a major issue, but in mountainous areas, on slopes, or in locations with surrounding obstructions, the choice of representative point can affect the analysis conditions. In practice, the area near the center of the layout or the main range of the power generation equipment is often treated as the representative point, but for unusual terrain it is reassuring to leave supplementary explanations.

Also, it is important to record the site conditions so that the assumptions are easy to check when reviewing the report later. In addition to the information entered in PVSyst, keeping internal analysis notes—such as the drawings referenced, survey data, site conditions, and date of verification—will be useful for reanalysis or when conditions change. If you are asked “why did this amount of generation occur?” it will also make it easier to explain the rationale for the site conditions.

Setting project information and site conditions are input items in the initial stage of the work, but they form the foundation of the analysis. If these are left ambiguous and you proceed, it will be difficult to improve the reliability of the results later, even if you adjust meteorological data or equipment settings. As an initial step, organize the project name, site, elevation, and analysis purpose, and document the rationale for the conditions.

Check meteorological data and solar radiation conditions

One of the factors that has a major impact on photovoltaic generation estimates is the meteorological data and solar radiation conditions. In PVSyst, annual energy production is simulated using meteorological data appropriate for the site. Solar irradiance, ambient temperature, and, when necessary, wind speed conditions are related to energy production and module temperature, and are indispensable for assessing the validity of the analysis results.

When setting weather data, the basic rule is to first select data that is close to the site. Even if the distance is short, meteorological conditions can differ in coastal areas, mountainous areas, urban areas, and basins. In particular, in snowy regions, areas prone to fog, or regions with large elevation differences, even data from nearby points can lead to differences in predicted power output. Therefore, rather than simply choosing the nearest data, check that it matches the climatic characteristics of the site.

Under solar radiation conditions, horizontal surface irradiance, tilted surface irradiance, the direct component, and the diffuse component all affect power generation calculations. If you are using PVSyst for the first time, these terms may seem difficult, but in practice it is important to check from the perspectives of "how much solar radiation the area receives," "how effectively the installation angle captures solar radiation," and "how to handle the effects of shading and weather." If the analysis results show power generation that is much higher or lower than expected, it is a good idea to first review the meteorological data and solar radiation conditions to see if anything seems off.

Air temperature is also an important factor. Solar modules generally tend to experience reduced output as temperature increases. Therefore, even with the same solar irradiance, energy generation varies depending on temperature and heat dissipation conditions. In regions that tend to become hot in summer, temperature losses can be significant. Conversely, under conditions of low temperature with available irradiance, output can be higher. When interpreting PVSyst results, check not only the annual solar irradiance but also the effects of temperature.

What you should avoid when handling meteorological data is uncritically using data whose source or conditions are unknown. In analysis work you may be tempted to reuse data you have on hand as-is, but if the location, period, whether any corrections were applied, and the representativeness of the data are unclear, it becomes difficult to explain the results. In particular, when comparing multiple analysis results, unless you verify that the meteorological data were collected under the same conditions, observed differences in power generation may be due to differences in meteorological conditions rather than differences in equipment or their deployment.

In practice, it is convenient to first estimate using standard meteorological data and then, as necessary, re-analyze under conditions closer to the site or under conservative assumptions. In proposal documents and internal approval materials, record which meteorological conditions were used to allow for future comparisons and verification. Meteorological data and solar radiation conditions are the very assumptions of the analysis. Carefully checking these makes the PVSyst results easier to explain.

Enter conditions for solar modules and conversion equipment

Once the site and meteorological conditions are set, next input the conditions for the solar modules and power conversion equipment. This step involves system capacity, number of modules, number of modules in series, number of modules in parallel, capacity of the conversion equipment, voltage ranges, and so on. In PVSyst analysis, equipment specifications affect energy production, losses, and the determination of the operating range, so it is important to enter data while cross-checking with design documents and specifications.

First, check the basic specifications of the solar modules. The main items are nominal output, temperature characteristics, voltage, current, dimensions, and number of modules. Because the installed capacity is determined from the nominal output and the number of modules, errors here can cause large deviations in the annual energy production results. When entering specification values, do not simply select the nearest value; verify that they match the equipment conditions you plan to use. If the official specifications have not been finalized, clearly state that the values are provisional to avoid confusion when replacing them with the finalized specifications later.

Next, set the number of modules in series and in parallel. How the solar modules are connected affects the input voltage range and current conditions of the power conversion equipment. If too many are placed in series, the voltage can become high at low temperatures, and if too few, it may be difficult to meet the required operating voltage range at high temperatures. In PVSyst you can configure the system while checking this electrical compatibility, but ultimately you must verify it against the design criteria and equipment specifications.

When configuring conversion equipment, check the rated capacity, number of input circuits, conversion efficiency, operating range, and so on. In photovoltaic systems, the ratio between module capacity and conversion equipment capacity affects power generation and the occurrence of output limitations. If the module-side capacity is large, some output may be limited during periods of strong solar irradiance. On the other hand, how to set the capacity ratio depends on the power plant’s design policy and regional conditions. In analyses, verify from the results the extent to which output limitations occur and determine whether they align with the design intent.

What you need to be careful about when entering equipment conditions is whether the specification values are misaligned with the actual plan. In the early stages of design, you may proceed using provisional modules or temporary power conversion equipment. If equipment changes later due to procurement or design modifications, the conditions in PVSyst must also be updated. If you use analysis results based on outdated conditions, the estimated power generation will not match the actual system configuration.

It is also necessary to consider how to handle equipment degradation and aging. Whether you want to look at first‑year generation or a long‑term average will change how you interpret the results. PVSyst may allow you to account for losses and aging degradation, but if you assume overly optimistic conditions the difference from actual operation can become large. In practice, it is desirable to use conservative, easy‑to‑explain assumptions that align with internal standards and the project’s objectives.

Organize the Effects of Placement, Tilt, Orientation, and Shadows

In solar power generation analysis, the orientation, tilt angle, and configuration of modules have a major impact on energy yield. In PVSyst, you set the tilt angle, azimuth, mounting-surface conditions, row spacing, and shading from surrounding obstacles to reflect how the solar irradiance is received. This procedure is an important part that connects design studies and analysis results.

The tilt angle indicates how much the module surface is inclined relative to the horizontal plane. Generally, the appropriate angle varies depending on the region and the design objective. When prioritizing annual energy yield, consider angles that take seasonal solar irradiance conditions into account. On the other hand, for rooftop installations or confined sites, the angle may be constrained by the building or mounting structure conditions. In PVSyst, you can compare multiple tilt angles and use the differences in energy yield and losses as input for design decision-making.

The azimuth indicates the direction the modules face. In Japan, modules facing closer to south often tend to achieve higher annual energy production, but site shape, roads, development conditions, wiring plans, and constructability mean the ideal azimuth cannot always be achieved. When arranging arrays split east–west or in installations that span multiple faces, it is necessary to organize the conditions for each face. When analyzing in PVSyst, verify that the azimuth entered matches the actual layout proposal.

Shading effects are also important. Surrounding buildings, trees, mountains, utility poles, fences, adjacent module rows, and so on can cause shading at certain times of day or during certain seasons. Shading does not simply make part of a surface darker; depending on the electrical connection conditions, it can affect power generation. PVSyst allows you to set shading conditions, but how detailed the shading model should be is determined by the project's objectives. At the preliminary estimate stage, grasp the general impact of shading, and at the detailed stage increase verification accuracy based on layout drawings and on-site conditions.

Row spacing also affects both energy production and land-use efficiency. Widening the row spacing makes it easier to reduce shading effects, but it can decrease the capacity that can be installed on the same site. Conversely, tightening the row spacing can increase the installable capacity, but it may increase losses from shading in winter and during mornings and evenings. In PVSyst, by comparing energy production while varying layout conditions, you can evaluate not just the nominal installed capacity but how much energy can actually be generated.

What should be noted regarding placement and shadow settings is that making the analysis model too detailed does not necessarily lead to better results. Even if you build a detailed model, if the underlying drawings or site conditions are inaccurate, the reliability of the analysis results will not increase. Conversely, if you oversimplify, you may overlook losses even when there are actually significant shadows. The important thing is to model at a level of detail appropriate to the analysis purpose and to record the assumptions.

Confirm loss settings and run the analysis

One of the items in PVSyst that tends to cause differences in energy generation is the loss settings. Losses include various factors such as temperature loss, wiring loss, soiling, equipment conversion loss, mismatch, shading, downtime, and degradation over time. How you configure these will change the result for annual energy production. As an introductory manual tip, rather than leaving losses "just at the default values", it is important to understand and verify the meaning of each item.

Temperature loss refers to the reduction in output caused by an increase in module temperature. Although stronger solar irradiance tends to increase power output, it also causes module temperature to rise. Because the way temperature increases depends on installation type and ventilation conditions, check the settings while taking into account installations close to the roof, ground-mounted installations, and racking height. Understanding how to assess temperature loss makes it easier to explain differences in power generation due to regional variations and installation conditions.

Wiring losses are the losses that occur when sending power from the modules to the power converters and further to the power receiving equipment. They depend on wiring length, conductor size, circuit configuration, voltage conditions, and so on. In the early stages of design the detailed wiring lengths may not be determined, but even in such cases care should be taken not to set unrealistically low loss values. When progressing to detailed design later, it is desirable to review and adjust the loss settings to match the actual wiring plan.

Losses due to soiling also vary with local conditions. The way soiling accumulates differs by environment — for example, heavy local dust, proximity to farmland or land development sites, closeness to the sea, susceptibility to bird fouling, or situations where the cleaning effect of rainfall is unlikely. Whether a cleaning plan is in place also affects energy production. Because PVSyst often treats this as a loss rate, it is important to set a defensible value that can be explained based on the site environment and maintenance policy.

Mismatch loss is the loss that occurs due to differences in characteristics between modules and differences in connection conditions. Because not all modules operate with exactly the same performance, it is necessary to anticipate a certain amount of loss. Localized shading or soiling can also affect the output of the entire circuit. In analysis, we not only look at the loss rate but also verify that it is not inconsistent with the layout and connection conditions.

How shutdowns and output curtailment are handled can also be important depending on the project. If periodic inspections, equipment outages, grid-side conditions, or control-imposed output limits are anticipated, they will affect annual energy generation. However, including uncertain elements in excessive detail can actually make explanations harder. In practice, it is effective to separate and organize confirmed conditions, generally expected conditions, and uncertain conditions, and to analyze multiple cases as needed.

After confirming the loss settings, execute the simulation. Before execution, review the main items: site, meteorological data, equipment configuration, capacity, tilt, azimuth, shading, and losses. In particular, check that the system capacity matches the assumptions, that the azimuth orientation has not been reversed, that loss rates are not set to extreme values, and that no provisional conditions remain. Because discovering an error in the assumptions after running the analysis will require rework, the checks performed before execution determine the quality.

Read analysis reports and translate them into areas for improvement.

When you output the PVSyst analysis results, don’t start by looking only at the annual energy production; review the entire report. Annual energy production is an easy-to-understand metric, but unless you understand the conditions that produced that figure, it is difficult to use for design improvements or explanatory materials. In the results report, review in sequence the input conditions, system capacity, meteorological conditions, breakdown of losses, monthly energy production, performance indicators, and so on.

The first thing to check is the input conditions. Confirm that the site listed in the report, meteorological data, system capacity, tilt angle, azimuth, and equipment configuration match the expected conditions. In analysis work, conditions from previous projects are sometimes duplicated. In such cases, the site name, azimuth, equipment conditions, or loss settings may remain outdated. Even if the results appear reasonable, they become unusable if the input conditions are different, so it is important to verify the assumptions first.

Next, review the trends in annual generation and monthly generation. Check whether the monthly generation deviates significantly from the region’s seasonal patterns and whether the changes in winter or summer look unusual. In systems with significant shading, losses can be pronounced in certain seasons or times of day. Comparing multiple cases with different tilt angles and orientations makes it easier to understand which conditions are affecting generation.

Checking the breakdown of losses is also essential. PVSyst's report lets you see what losses occur at each stage from solar irradiance to the final energy production. If any particular loss is excessively large, it is necessary to review the input conditions or design parameters. For example, if shading losses are large, reconsider the layout and row spacing; if temperature losses are large, check the mounting arrangement and ventilation conditions. If wiring losses are large, you may need to review the wiring plan or circuit configuration.

Performance indicators are also useful for evaluating the validity of results. Checking how much annual generation there is relative to installed capacity and what the overall system efficiency is makes it easier to compare with other conditions and past projects. However, because performance indicators vary depending on region and installation conditions, it is important not to judge them solely by whether they are simply high or low. Assess validity by looking at weather conditions, tilt, orientation, losses, and whether any output limitations exist.

To improve analysis results, consider separately the factors that increase power generation and the factors that can realistically be changed. Even if changing the tilt angle or azimuth would increase power generation, they may not be changeable due to the site, racking, or construction conditions. Even if widening the row spacing reduces shading losses, it may reduce the installed capacity. Changing the capacity ratio of the conversion equipment can in some cases mitigate output limitations, but it must be consistent with the overall design policy of the facility.

PVSyst results are a basis for design decisions and should not be used alone as the final determinant. Based on the analysis results, it is important to comprehensively verify energy production, constructability, maintainability, site utilization, equipment configuration, and the ease of explaining the documentation. Improving your ability to read result reports allows you not only to run analyses but also to achieve design improvements and higher proposal quality.

Precautions for Stable Operation of PVSyst in Practice

To use PVSyst continuously in practical work, you need not only individual operational skills but also a system to standardize conditions across the company. If loss rates, naming rules, and choices of meteorological data differ among staff, results can vary even for the same project. When analysis results are used in internal documents or for client presentations, it is important to ensure reproducibility and explainability.

First, it is effective to establish standard conditions. By codifying as internal rules the loss settings used for preliminary estimates, the items to be reviewed in detailed studies, the input values that must be checked, and the checklist to use before submitting reports, it becomes easier to maintain consistent quality even when personnel change. However, if you fix the standard conditions too rigidly, it becomes difficult to reflect site-specific special conditions. Separating items that use standard values from those adjusted on a per-project basis makes it easier to fit practical work.

Next, it is important to develop a habit of leaving analysis notes. PVSyst files alone can make it difficult to understand why certain conditions were chosen, which documents were used as the basis, and which items are provisional. For each analysis, record the project in question, creation date, person responsible, meteorological conditions used, equipment specifications, main loss settings, unresolved items, and changes since the previous analysis; this will make it easier to make judgments when you review them later.

When conducting comparative analyses, it is important to make each change clear one by one. If tilt angle, azimuth, equipment capacity, loss rate, and shading conditions are changed simultaneously, it becomes difficult to identify the causes of differences in power generation. First create a reference case, then change one condition at a time and compare; this makes it easier to explain which factors are affecting the results. In internal reviews, this comparison process serves as the basis for design decisions.

Also, caution is required when reusing files from past projects. Reusing files can improve work efficiency, but there is a risk that old site conditions, outdated equipment specifications, unnecessary shading models, and previous loss settings may remain. When reusing files for a new project, do not just change the filename; check the site, capacity, orientation, losses, and equipment specifications one by one. In particular, if the display names and notes that appear in reports are left as they were from past projects, they will undermine the credibility of the documentation.

When using PVSyst analyses in materials intended for external parties, pay attention to the wording. The analysis results are estimates based on the input conditions and do not constitute a complete guarantee of future actual power generation. Therefore, avoid expressing power generation too definitively, and word it so that it is clear the figures are estimates based on the assumptions. If uncertain equipment specifications or provisional loss conditions are being used, it is safer to state that they may be changed at a later date.

Finally, comparing actual results after analysis is also important. After the plant begins operation, comparing the actual generation with PVSyst estimates allows you to verify whether the initial settings and loss assumptions matched the site conditions. If there is a discrepancy with actuals, check multiple factors separately — differences in meteorological years, outages, soiling, shading, equipment malfunctions, curtailment, metering conditions, etc. By accumulating these verifications, you can improve the accuracy and explanatory power of future analyses.

Summary: Master PVSyst analysis by organizing conditions and checking results

PVSyst is a useful analysis software for estimating the power generation of solar power plants, but to use it correctly, organizing input conditions and interpreting results are indispensable. By understanding the entire workflow—from initial settings, site conditions, meteorological data, equipment configuration, layout, shading, and losses to verification of analysis results—you can perform analyses that are usable in practice rather than merely operating the software.

What's particularly important is not to judge solely by the annual energy production in the analysis results. You need to check which site conditions were used, which meteorological data were referenced, whether the tilt and azimuth angles match the actual layout, and whether the loss settings are overly optimistic for the site conditions. PVSyst reports are useful not only for the energy production figures but also as documentation for interpreting the assumptions and loss breakdowns, which can aid in design improvements and internal explanations.

New users responsible for using PVSyst for the first time will find it easier to understand if they first grasp the flow of the seven steps. First, get an overview, complete the initial settings, and configure the project and site conditions. Next, review the meteorological data and irradiance conditions, and enter the specifications for the PV modules and power conversion equipment. Then organize the layout, tilt, azimuth, and shading, check the loss settings, and run the analysis. Finally, read the analysis result report and use it to identify improvements and prepare explanatory materials.

In practice, because conditions differ for each project, it is not always possible to handle them with exactly the same settings. That is why it is important to have standard procedures and internal rules, separate provisional conditions from finalized conditions, and proceed with analysis while keeping a record of changes. Once you can use PVSyst reliably, it becomes easier to compare options in the early design stage, consider equipment configurations, explain differences in energy yield, and organize loss factors.

In planning a solar power plant, it is necessary to consider not only analysis but also understanding site conditions, examining earthworks and layout, constructability, maintainability, and post-completion management as an integrated whole. By handling the energy yield estimates obtained from PVSyst while cross-checking them with on-site survey data and design information, it becomes easier to reduce discrepancies between desk-based figures and field conditions. Not only learning to operate PVSyst by referring to the manual, but also running it in a way that includes organizing conditions, recording the basis for assumptions, and validating results leads to analyses that are usable in practice.