6 Points to Check for Ground-Mounted Projects in the PVSyst Manual

Table of Contents

• What it means to review ground-mounted projects in the PVSyst manual

• Assumptions that are easy to overlook in ground-mounted installation projects

• Checkpoint 1: Align site conditions with meteorological data

• Checkpoint 2: Align the azimuth and tilt angles with the project conditions

• Checkpoint 3: Realistically verify row spacing and mutual shading

• Checkpoint 4: Do not underestimate nearby shading and terrain shading

• Checkpoint 5: Align module, inverter, and string conditions

• Checkpoint 6: Make loss settings and report results explainable

• Practical checks when using PVSyst for ground-mounted projects

• Summary

The Significance of Reviewing Ground-Mounted Installations in the PVSyst Manual

Many people who consult the PVSyst manual are not simply looking to learn how to operate the interface; they want to know how to verify, in practice, the design and energy-yield simulations of photovoltaic projects. Especially for ground-mounted projects, compared with rooftop installations, there are many more items to consider—site conditions, azimuth, tilt angle, row spacing, shading, topography, wiring, and the configuration of power conditioners. Therefore, it is important not only to operate the PVSyst screens in sequence but also to understand how each setting is reflected in energy yield, losses, and report results.

PVSyst is software used for the evaluation, sizing, and data analysis of photovoltaic power systems, and it includes features to handle multiple system types such as grid-connected, standalone, pumping, and DC-grid systems. Even for ground-mounted projects, it is important to use it not merely as a power-generation calculation tool but as a tool to organize design conditions, visualize loss factors, and provide a basis for explaining the design to stakeholders.

For ground-mounted projects, even with the same module capacity, energy output changes depending on the layout and row spacing. In addition, site slope, nearby buildings and trees, racking height, array orientation, string configuration, and wiring distance interact in complex ways. When reading the PVSyst manual, you should not memorize functions in isolation; instead, be aware of what each function is meant to check in an actual project.

In this article, we summarize six key points practitioners should check when verifying ground-mounted projects in PVSyst. These verification points can be used to prevent missed settings and insufficient explanations, both for those using PVSyst for the first time and for users already familiar with the basic operations.

Assumptions Easily Overlooked in Ground-Mounted Installation Projects

In ground-mounted solar power projects, the design freedom is high, but the validity of input conditions has a large impact on the results. For rooftop installations, the roof orientation and pitch are to some extent predetermined, so simulation conditions can be organized according to the building conditions. In contrast, for ground-mounted installations, the design side often has to decide the azimuth, tilt angle, row spacing, racking height, access aisles, maintenance space, terrain slope, and site development conditions.

Therefore, just because you can enter values into PVSyst, adopting only the conditions that maximize power generation may not be compatible with actual construction and maintenance. For example, narrowing the row spacing can increase the installed capacity, but it may increase inter-row shading in winter or leave insufficient access for maintenance work. Conversely, widening the row spacing reduces the impact of shading, but it may reduce the capacity that can be installed within the same site area.

When consulting the PVSyst manual, it is important to first clarify the project's assumptions and consider which screens in PVSyst should reflect those assumptions. If you proceed with simulations while site area, available installation area, orientation, tilt, ground conditions, surrounding obstructions, point of connection, planned equipment, design capacity, and power generation targets, etc. remain unclear, the report may look tidy but will produce results that are difficult to use for design decisions.

Simulating ground-mounted projects is not just a task of producing power output. It is a process of checking whether the design proposal is realistic, how much shading and losses are being anticipated, and whether the results can be explained to third parties. Keeping these points in mind makes it clear what to prioritize on each screen of PVSyst.

Checkpoint 1: Align site conditions with meteorological data

The first point to check is the consistency between site conditions and meteorological data. In PVSyst, solar radiation and power generation are calculated based on the project's location information and meteorological data. For ground-mounted projects, sites are often located in mountainous areas away from urban centers, reclaimed land, agricultural land, industrial parks, coastal areas, and so on, and the nearest meteorological data may not perfectly match the actual site conditions.

Latitude, longitude, elevation, time zone, and the type of meteorological data used form the basis of energy production simulations. Before checking annual and monthly energy production in PVSyst reports, you should first verify that the entered location information corresponds to the project site. This is especially important for ground-mounted projects, where the choice of a representative point within a large site matters. On mountain slopes or uneven terrain, irradiance and shading conditions can vary even within the same site.

The PVSyst tutorial also explains that the accuracy of location information can affect the simulation. For ground-mounted projects, the basic practice is not to enter latitude and longitude roughly but to make them as close as possible to values that reflect the actual planned site.

Regarding meteorological data, the nature of the results changes depending on which database you use, whether you use measured data, or whether you use average-year (typical year) data. Whether you want to conduct an analysis close to past actual performance, produce a rough estimate in the early design stage, or prepare explanatory materials for financing or contracts will change the required level of accuracy and the content of your explanations. When consulting the PVSyst manual, it is important to be mindful not only of the procedure for selecting data but also of whether you can explain the rationale for the data you have chosen.

Also, for ground-mounted projects, the surrounding environment cannot be overlooked. In snowy regions, high-wind regions, salt-affected regions, high-temperature regions, and areas with frequent fog, there are factors that affect design and loss assumptions beyond simple irradiance. Although not all environmental risks can be represented directly in PVSyst, it is necessary to check whether there are elements that should be reflected in the settings for temperature losses, soiling, downtime rates, degradation, and shading.

What matters when checking site conditions and meteorological data is not just making the numbers more detailed. It is ensuring you can later explain the assumptions under which the simulation was run. When submitting a PVSyst report, you will be asked not only for the energy production figures but also which specific location, which meteorological data set, and which design conditions those figures are based on. If you proceed with these points left unclear, later stages will often require recalculation.

Verification Point 2: Align azimuth and tilt angles with project requirements

Next, it is important to check the azimuth and tilt angles. In ground-mounted projects, it is common to consider a south-facing orientation and an optimal tilt angle to maximize power generation, but in practice the ideal orientation and angle cannot always be adopted as-is due to site shape, site development limits, roads, drainage, adjacent property boundaries, the location of grid interconnection equipment, maintenance access routes, and so on.

In PVSyst you can set the array azimuth and tilt angles and check their impact on energy production. The important point here is not simply to find the combination that yields the highest energy output, but to compare options within ranges that are reasonable as design conditions. For example, increasing the tilt angle can be advantageous for winter solar gain, but it lengthens inter-row shading and affects wind loads, racking costs, and constructability. Lowering the tilt angle can reduce inter-row shading, but may make soiling harder to wash off and may limit winter energy production.

The same applies to azimuth. While a layout close to true south is often advantageous, when the site is elongated or there are constraints in the development plan, a layout shifted slightly toward the east or west can be more advantageous overall. When comparing multiple cases in PVSyst, it is necessary to consider not only energy yield but also installed capacity, shading losses, land-use efficiency, constructability, and maintainability.

PVSyst's documentation indicates that orientation settings such as azimuth and tilt are also related to shading settings. In particular, when creating a 3D shading scene, if the system's azimuth conditions and the 3D scene's orientation are not aligned, evaluating shading and interpreting reports becomes difficult.

A common mistake in ground-mounted projects is to carry the azimuth and tilt angles from the initial study straight through to the detailed design phase. While a rough layout may be acceptable at the preliminary stage, layout conditions can change as survey results, site formation plans, racking specifications, and electrical design progress. If you don’t update the conditions in PVSyst each time, the reported energy yield will diverge from the actual design drawings.

If you plan to use the PVSyst manual in practice, azimuth and tilt angles should not be treated as values entered once and forgotten; they should be items to check whenever the design changes. This is especially important for ground-mounted installations, where it is crucial to ensure consistency among the site plan, layout drawing, racking drawings, single-line wiring diagram, and PVSyst settings. If the design drawings show a changed tilt angle but PVSyst still uses the old conditions, the reliability of the energy yield and loss assessments will decrease.

Checkpoint 3: Realistically verify row spacing and mutual shading

One of the most important items to check in ground-mounted projects is inter-row spacing and mutual shading. In ground-mounted installations multiple rows of racking are placed side by side, so modules in the front row can cast shadows on modules in the rear row. The impact of inter-row shading tends to be especially large during winter mornings and evenings when the solar altitude is low, and in designs with large tilt angles.

If you reduce the row spacing, you can place more modules on the same site. This is advantageous in terms of increasing installed capacity. However, if shading losses increase, the energy output may not rise in proportion to the increased capacity. Furthermore, if mismatch losses caused by shading become large, they affect not only the annual energy yield but also the generation pattern by time of day.

On the other hand, widening the row spacing makes it easier to reduce shading, but it lowers land-use efficiency. For ground-mounted projects, land costs, site development costs, fencing, roads, drainage, and maintenance access routes are also involved, so decisions should be made based on overall project viability, not just maximizing power generation. The PVSyst simulation results should be used as one of the inputs for that decision.

PVSyst's near shading feature lets you use 3D scenes to model shadows from nearby obstacles and between arrays. The official documentation also states that near shading is one of the more challenging parts of PVSyst, and that creating 3D scenes and assessing shadows requires specific procedures and practice.

When checking row spacing, it's important not to judge based solely on annual power generation. Check monthly generation, shading losses, winter declines, and morning/evening impacts to see whether they align with the design intent. For example, in projects where winter feed-in tariffs or demand patterns are important, or in self-consumption projects where generation in the mornings and evenings has value, it can be difficult to judge based on a simple annual total.

Also, for ground-mounted installations, the height of the racking and variations in the terrain also affect inter-row shading. Even if the site is set as flat, if the actual site has a slope, the way shadows appear may change. It is important to confirm that the finished grade after site preparation, the height of the racking foundations, and the slope of the ground surface do not differ significantly between the design drawings and the PVSyst settings.

Checking row spacing and mutual shading is most effective in the early stages of design. If you discover after the design is finalized that shading losses are large, you will need to change the layout, adjust capacity, or revise equipment configuration, resulting in significant rework. When reading the PVSyst manual, it is useful in practice to be aware not only of how to operate the shading functions but also of when shading assessments should be performed.

Checkpoint 4: Do not underestimate nearby and terrain shading

For ground-mounted projects, attention must be paid not only to mutual shading between arrays but also to nearby shading and terrain shading. Nearby shading refers to shadows produced by objects located close to the solar panels, such as buildings, trees, utility poles, fences, adjacent equipment, slopes, and grade changes in developed land. Terrain shading refers to shadows caused when the sun is blocked by mountains, hills, or surrounding elevation differences.

Ground-mounted projects are often planned in suburban areas, mountainous regions, or developed/graded sites, and there may be elevation differences in the surrounding area. Even small terrain differences that are easy to overlook on site can cause shading effects during winter mornings and evenings. If simulations in PVSyst do not adequately reflect surrounding obstacles and terrain, they may overestimate actual energy production.

In PVSyst's near shading settings, you can create shading scenes using the 3D editor and calculate the effects of shading. The main near shading screen is described as the entry point to access the 3D editor, and after creating a shading scene, compatibility with system-defined elements is also checked.

However, it is not enough to simply create a 3D scene. For ground-mounted projects, the important thing is to determine how much detail should be reproduced. Modeling every small object in detail increases the workload and makes model management difficult. Conversely, omitting obstacles that are likely to cast shadows in reality reduces the reliability of the results. Therefore, it is practical to prioritize checking items that are likely to have an impact during times of low solar altitude, those close to the array, and tall objects.

Care should also be taken in how trees are handled. Even if they appear to cast little shade during a site inspection, foliage density can change with the seasons and they may grow over the next few years. Whether they are scheduled for removal, are trees on neighboring land, or can have their height controlled through maintenance will affect how they should be treated in PVSyst. You need to clarify whether to assess shading conservatively, to base it on current conditions, or to present it separately as a future risk.

Terrain shading is particularly important for projects with surrounding mountains or hills. Even if a site appears to be open to the south, mountains or high ground to the east or west can affect generation in the morning and evening. Even if the impact on annual generation seems small, there can be large differences in certain months or specific time periods. For projects aimed at self-consumption or peak shaving, time-of-day generation characteristics are also important, so it is essential not to underestimate terrain shading.

When reading the PVSyst manual, you need to consider not only how to use the near-shading feature but also how to integrate it with on-site surveys and design drawings. Using drone photos, survey data, layout plans, grading plans, and surrounding photographs to check that the shading conditions in PVSyst are not significantly different from reality will enhance the explanatory power of the report.

Checkpoint 5: Align module, inverter, and string conditions

The fifth checkpoint is the consistency among module, inverter, and string conditions. In ground-mounted projects, as the installed capacity increases, the impact of equipment configuration and string design becomes greater. When calculating energy production in PVSyst, important input parameters include module type, number of modules, tilt, azimuth, inverter capacity, MPPT configuration, number of strings, and number of modules in series.

If the design drawings or single-line connection diagrams are not aligned with the PVSyst settings, the reliability of the simulation results will decrease. For example, if PVSyst calculates using a specific number of modules but the actual layout shows a different number, both energy production and losses will change. Changes to inverter capacity or the number of inverters will also affect the oversizing ratio, clipping, and operating range.

For ground-mounted installations, string length is also important. The number of modules connected in series in a string is related to the module voltage characteristics, the minimum temperature, the maximum temperature, and the inverter's input voltage range. You should not only check whether PVSyst raises any warnings, but also separately verify that there are no problems from an actual electrical design perspective. Especially in cold climates, high open-circuit voltage at low temperatures and reduced operating voltage at high temperatures can become problematic.

Also, in projects where multiple azimuths or multiple tilts coexist, it is necessary to check whether strings under different conditions are connected to the same inverter or MPPT. In ground-mounted installations, arrays are generally laid out under the same conditions, but depending on site shape or terrain, the orientation or tilt of some arrays may change. In such cases, the handling of orientations in PVSyst must also be organized appropriately.

For projects affected by shading, the relationship between module layout and string configuration is also important. PVSyst has a module layout feature to calculate electrical mismatch losses caused by shading in detail, and it requires describing the position of each module within the 3D scene and the string connection relationships as defined on the inverter side.

Whether to use this feature depends on the project scale and the stage of evaluation, but at minimum you should be aware of the relationship between where shadows occur and the string configuration. For example, if only part of a row is shaded in the morning, the way losses manifest will vary depending on which string that shading affects. You need to consider the electrical connections, not just the simple shaded area.

When checking ground-mounted projects using the PVSyst manual, don’t stop at simply selecting components from the equipment database; always verify that the selected equipment actually matches the design specifications. It is important to cross-check the manufacturer model number, rated capacity, temperature coefficient, inverter capacity, number of MPPTs, input range, and string configuration against the design documents.

Checkpoint 6: Make loss settings and report results explainable

The final checkpoint is to make the loss settings and the report results explainable. In PVSyst reports, various losses are organized from irradiance to final energy production. For ground-mounted projects, temperature losses, wiring losses, mismatch losses, soiling, shading losses, inverter losses, and assumptions about downtime and degradation are important.

A common pitfall for beginners is treating the report produced by PVSyst as a correct result as-is. However, simulation results depend heavily on the input conditions and loss settings. Just because numbers are displayed in detail does not mean the results will be usable in practice if the underlying assumptions are not reasonable.

In ground-mounted projects, we first check for each loss item whether the default value is acceptable or should be adjusted according to the project conditions. For example, in large-scale projects with long wiring distances, it is necessary to appropriately consider wiring losses on the DC and AC sides. In projects in dry areas, locations with heavy dust, near agricultural land, or along unpaved roads, soiling losses may not be negligible. In high-temperature regions, temperature losses can become significant.

For shading losses, the meaning of the results changes depending on whether a 3D scene has been created or not. In PVSyst you can also simulate a project without setting shading, but in that case you must separately define the field orientation and tilt. When using a shadow scene, you need to make the system orientation consistent with the conditions of the 3D scene.

When reviewing a report, we look not only at annual energy production but also at monthly energy production, performance ratio, loss diagram, shading losses, inverter losses, clipping, available solar irradiance, and so on. In particular for ground-mounted projects, winter shading, summer temperature losses, clipping during overloading, and wiring losses often become the key points to explain.

When power generation is lower than expected, check which losses are large. It is important to distinguish whether shading losses, temperature losses, wiring losses, or inverter capacity selection is the cause. Conversely, be cautious if generation is too high. Shading, soiling, downtime rate, or wiring losses may not have been adequately accounted for.

The purpose of using the PVSyst manual in practice is not just to learn how to operate the interface. Ultimately, it is to be able to explain the figures in the report to stakeholders. Owners, designers, contractors, financial institutions, and O&M personnel each have different concerns. Designers focus on losses and the consistency of equipment configuration; owners on annual energy production and the project’s economic viability; and O&M personnel on shading, soiling, and maintenance conditions.

Therefore, when reviewing a PVSyst report, you need to read it while thinking about which figures you will explain to whom. If there are loss settings you cannot explain or input conditions with unclear justification, they should be reviewed before submitting the report.

Practical checklist when using PVSyst for ground-mounted projects

When using PVSyst for ground-mounted projects, deciding the workflow in advance can reduce mistakes. First, organize the project's basic conditions. Confirm the site location, installed capacity, planned modules, inverter, racking conditions, azimuth, tilt angle, row spacing, surrounding obstacles, and assumptions for meteorological data. Then input these into PVSyst and perform an initial simulation.

During the initial simulation stage, it is important not to overestimate the accuracy of the results and to examine sensitivity. Check how much the energy production and losses change when the azimuth is slightly altered, when the tilt angle is changed, when the row spacing is changed, and with and without shading conditions. This comparison will reveal which design factors are important for the project.

Next, verify consistency with the design drawings. Confirm that the module count, orientation, tilt, number of arrays, number of inverters, and string configuration in PVSyst match the site layout and single-line wiring diagram. Because ground-mounted projects are prone to design changes, be careful that the PVSyst settings have not been left as an outdated design.

Additionally, we will verify shadows and losses. We will document the extent to which inter-row shading, nearby shading, and terrain shading are being accounted for, so that this can be explained in the report. If shadows are not modeled in detail, clearly stating the reasons and the current stage of evaluation will make later explanations easier.

Finally, we review the report results. We check annual energy production, monthly energy production, performance ratio, loss items, shading losses, temperature losses, wiring losses, and inverter losses, looking for any abnormally large or small values. The PVSyst results serve not only as input for design decisions but also as documentation used to build consensus among stakeholders.

In ground-mounted projects, the person responsible for PVSyst settings and the person responsible for design are sometimes different. In such cases, if the handover of input conditions is unclear, the simulation and the design documentation can easily diverge. The PVSyst operator should not simply run the calculations; they should record which design drawings, which equipment lists, which meteorological data, and which shading conditions were used.

Also, PVSyst results are not something you create once and forget. Their use changes at each stage—basic design, detailed design, pre-construction verification, and post-completion comparison. In the initial stage they are used to compare multiple options; in the detailed stage to finalize design values; and after construction to compare with actual energy production. For ground-mounted projects, it is important to update PVSyst settings at each stage and to manage which version of the report corresponds to which design option.

Summary

When reviewing ground-mounted projects in the PVSyst manual, simply memorizing the sequence of screen operations is not enough. For ground-mounted projects, site conditions, meteorological data, azimuth, tilt angle, row spacing, nearby shading, terrain shading, equipment configuration, string conditions, and loss settings are intricately interrelated. It is important to check each of these one by one and be able to explain them as part of the report results.

What is particularly important is to review the six verification points in line with the project workflow. First, reconcile the site conditions with the meteorological data, then adjust the azimuth and tilt angles to match the actual design conditions. Next, check row spacing and mutual shading, making sure not to underestimate nearby shadows or terrain shading. Furthermore, align the module, inverter, and string parameters with the design documents, and finally configure the loss settings and make the report results explainable.

PVSyst is not a tool that automatically produces the correct energy yield; it is a practical tool for organizing design conditions and evaluating energy production and losses. If the input conditions are ambiguous, the output results will also be ambiguous. Conversely, if site conditions, shading, equipment configuration, and losses are checked carefully, PVSyst reports become useful documents for design decisions and for explaining projects to stakeholders in ground-mounted installations.

For ground-mounted projects, it's important to adopt an attitude of verifying the assumptions behind the power generation figures, not just the figures themselves. When using the PVSyst manual, always be mindful not only of which screen to enter what, but whether those input values match the site conditions, design drawings, construction conditions, and operation and maintenance conditions. By doing so, you can use PVSyst not merely as an operating manual but as a verification procedure for power generation simulations that is usable in practical work.