【How to Set a Location in PVSyst｜Explained in 5 Steps from Site Selection】

Table of Contents

• Why PVSyst location settings affect simulation accuracy

• Step 1: Organize basic information about candidate sites

• Step 2: Verify latitude, longitude, and elevation

• Step 3: Create a new location in PVSyst

• Step 4: Link meteorological data with the location information

• Step 5: Checklist items to verify after input

• Common mistakes in location settings and how to fix them

• Practical approaches to streamline location setup in practice

• Leverage on-site positioning data to improve design accuracy

• Summary

Why PVSyst Site Settings Affect Simulation Accuracy

When simulating the energy yield of a solar power plant with PVSyst, the first thing to consider is not the system size or the panel model, but the site where the plant is assumed to be located. A site does not simply mean an address or place name. In the simulation, it is the information that forms the basis for energy output calculations, including latitude, longitude, elevation, time zone, meteorological data, solar irradiation conditions, and temperature conditions.

In solar power generation, even with the same installed capacity, annual energy output varies depending on the region where the system is installed. Regions with higher solar irradiance tend to see greater output, while regions with frequent cloudy conditions or snowfall tend to have suppressed output. Temperature also affects generation. Solar panels are not simply better with stronger sunlight; if temperatures are too high, output can decline. Therefore, it is important to appropriately reflect the local meteorological conditions.

In PVSyst, you set a location, select the meteorological data corresponding to that location, and apply it to the power generation simulation. In other words, if you proceed with an ambiguous location setting, no matter how detailed the conditions entered in later steps are, the overall reliability of the simulation will decline. In practice, simulation results are often used for candidate-site comparisons, project feasibility assessments, design reviews, materials for financial institutions, and internal approval documents. For this reason, location setting should be considered not as a "simple input item to complete at the start" but as an "important process that determines the assumptions of the simulation."

Also, first-time PVSyst users may feel that the task is complete simply by selecting a location on the screen. In reality, however, you need to make decisions such as where to place the representative point for a candidate site, which point to use as the reference when the site is large, which source to use to verify elevation, and how to assess the distance and differences in conditions relative to the meteorological data. Understanding these points will enable you to configure site locations not just as procedural steps but in a way you can justify in professional practice.

Step 1 Organize basic information about candidate sites

Before setting up a location in PVSyst, first organize the basic information for the candidate site. Rather than creating the location directly in the software, preparing the necessary information in advance reduces input errors and backtracking. In practice, it is smoother to organize the candidate site's address, parcel number, site boundaries, surrounding environment, approximate elevation, planned usable area, orientation, slope, and whether land development/grading is required before starting work.

What is especially important is to decide at the outset whether to treat a candidate site as a single point of information or as the entire parcel. For small rooftop installations or narrow sites, using a point near the center of the building or property as a representative point often does not cause major problems. On the other hand, for large sites such as ground-mounted solar power plants, elevation, slope, and shading conditions can change from one end of the site to the other. In such cases, it is important not to simply use the address center, but to use as the reference the center of the area where panels will actually be placed or a location that is representative of the power generation facilities.

When organizing the basic information for candidate sites, also check the planned power plant boundaries and surrounding obstructions. If there are mountains, hills, forests, buildings, transmission towers, slopes, existing facilities, etc. nearby, they will affect not only the site placement itself but also later shading settings and layout considerations. Even if you correctly input only the site's latitude and longitude, ignoring surrounding conditions can result in outcomes that do not closely reflect the actual power generation.

Also, when there are multiple candidate sites, it is important to organize the information according to the same criteria. If Candidate site A is the site center, Candidate site B is the address representative point, and Candidate site C is near the entrance—i.e., if the reference points are inconsistent—the fairness of the comparison decreases. At the candidate selection stage, verify the location information for each candidate at the same level of granularity and set the representative point using the same approach.

The goal at this stage is not just to decide the values to input into PVSyst. It is to be in a state where you can later explain why this location was chosen as the reference. In practice, there are cases where the validity of the assumptions is given more weight than the simulation results themselves. By organizing the rationale for the site selection, it becomes easier to explain to both internal and external parties.

Step 2 Check latitude, longitude, and elevation

Once the basic information for the candidate site has been organized, the next step is to check the latitude, longitude, and elevation. In PVSyst's site settings, these location parameters form the basis for the power generation simulation. Latitude and longitude relate to the sun's path and solar irradiance conditions, while elevation affects how temperature and atmospheric conditions are handled. In practice, it is important not to rely solely on the address; always verify these values numerically.

When checking latitude and longitude, clearly define the representative point of the candidate location. Decide whether the representative point will be the site center, the center of the panel layout area, the center of major equipment, or a reference point used in simulations. For large sites, it is more natural to use a point closer to the center of the area where the solar panels will actually be installed rather than the entrance or the management building. Especially on sloped or elongated sites, the choice of representative point can affect how elevation and surrounding shading are interpreted.

You also need to pay attention to the format of latitude and longitude. Position information can be in degrees-minutes-seconds format or in decimal format. When entering data into PVSyst, you must match the format requested on the screen. If you make mistakes with the sign or the decimal point during conversion, you may specify a completely different location. For locations within Japan, latitude is generally treated as north (N) and longitude as east (E), but check the input field format and how signs are handled before entering.

Regarding elevation, rather than simply inferring it from the place name, confirm values as close to the candidate site as possible. While an elevation difference of a few meters may not cause major problems, in mountainous areas, sloped terrain, plateaus, or reclaimed land, elevation differences can affect meteorological conditions and design judgments. Also, when there are large elevation differences within the site, it is necessary to consider which elevation to use as the representative value. It is easier to explain if you use the average elevation of the area where the power generation equipment will be installed, or the elevation of the main installation area as the reference.

I recommend recording the latitude, longitude, and elevation so they can be verified later. Instead of leaving this information only in the PVSyst project file, also record it in the design conditions summary sheet and in internal memos; this is useful when multiple people are working on the project. If the person responsible changes or you review the simulation conditions at a later date, you will immediately know which location information was used.

A common mistake when setting the site location is being satisfied with merely looking up the candidate site's address and then using a point that is actually far from the real power generation area. The representative point of an address can indicate the site entrance or a location near a building. If it is offset from the power plant’s layout area, using that point as-is will make it difficult to reconcile later layout work and shading analyses. When choosing the point to use in PVSyst, it is important to decide based on whether it truly represents the location where you want to evaluate the power generation.

Step 3 Create a new location in PVSyst

After confirming the latitude, longitude, and elevation, set the site in PVSyst. The basic flow is to create a new site from the project creation or site management screens and enter the place name, country or region, latitude, longitude, elevation, and so on. The screen layout may look different depending on your environment and version, but it is easier to understand if you think of it as registering the simulation site and linking that site to the project.

Choose location names that will still be understandable later. For example, names like "Candidate Site 1" or "Site A" alone can easily cause confusion as the number of projects increases. In practice, it is convenient to create easily identifiable names by combining the project name, region, intended use, creation date, type of representative point, and so on. However, if there are internal rules or file management rules, standardize according to them. When location names are well organized, it is easier to manage comparisons of multiple candidate sites and to create simulations for the same project under different conditions.

When entering latitude and longitude, pay attention to the number of decimal places. If you round excessively, the location can shift by tens to hundreds of meters (tens to hundreds of ft). While this may not be a major issue when comparing candidate sites on a large scale, for studies closer to detailed design it is preferable to use the most accurate values possible. In particular, for rooftop installations or sites with complex conditions, the accuracy of the representative point will affect later explanations.

When entering elevation, also check the unit. Confirm whether it is entered in meters (ft) or another unit to prevent unnecessary conversion errors. Elevation's impact on power generation is not as intuitive as latitude and longitude and is therefore often overlooked, but it's important to keep it consistent as part of the location information. After inputting, review to make sure the value you confirmed during site selection matches the value entered into PVSyst.

After creating a new location, confirm that it is correctly selected in the current project. Simply registering a location does not always reflect it in the project. When working with multiple locations, a previously created location may still be selected. Make it a habit to check on the project screen that the target location is correct before running a simulation to reduce the risk of performing calculations under the wrong conditions.

Also, in PVSyst, site configuration and meteorological data settings are sometimes treated as separate tasks. Simply creating a site does not necessarily mean that the meteorological data required for the energy yield calculation have been appropriately selected. Therefore, once site creation is complete, next confirm the linkage with the meteorological data. Thinking of site configuration not as a standalone task but as a process to be checked together with the meteorological data settings will reduce practical mistakes.

Step 4 Link weather data with location information

After setting the site in PVSyst, select the meteorological data corresponding to that site. In solar power generation simulations, meteorological conditions such as irradiance, temperature, and wind speed greatly affect power output. Even if the site information is correct, if the meteorological data is far removed from the actual candidate location, the reliability of the simulation results decreases. Therefore, the association between site settings and meteorological data must always be verified together.

When selecting meteorological data, first check the distance to the candidate site. Data closer to the candidate site is not necessarily better, but the farther away it is, the more likely the meteorological conditions will differ. Especially in mountainous areas, coastal areas, basins, plateaus, and snow-prone regions, differences of several tens of kilometers (several tens of miles) can change solar radiation, temperature, snow cover, and cloud patterns. Rather than simply choosing the nearest station, it is important to also consider similarity in terrain and climate.

Next, we will look at the types of meteorological data. The meteorological data used in simulations include datasets that represent long-term average weather conditions and those that are close to actual measurements for a specific period. In project feasibility assessments, conditions close to long-term averages are often used, because judging solely on short-term observed values can make results more susceptible to year-to-year weather bias. Which type of meteorological data to use depends on the purpose of the simulation.

In the initial stage of site selection, when comparing multiple candidate sites it is important to choose meteorological data using the same approach. If conservative data are used for one candidate and optimistic data for another, the comparison will be unfair. Even if the sources or conditions of meteorological data differ between candidates, harmonize the selection criteria and be able to explain the reasons for any differences.

Once the meteorological data are linked, we check monthly solar irradiance and temperature trends in PVSyst. We look for any extremely high or low values and whether they significantly contradict the regional characteristics of the candidate site. For example, if an area that should be cold appears warm year-round, if a region expected to receive snow shows unnaturally favorable winter solar conditions, or if coastal and mountainous conditions seem to be mixed, we reassess the selection of the location and the meteorological data.

Also, meteorological data is not something that is finalized once selected. As the design stage progresses, more detailed conditions of candidate sites may become apparent. On-site surveys, surveying, land development plans, shadow checks, and changes in the surrounding environment can all necessitate selecting more appropriate data. Even if a simplified location setting is used for initial assessments, it is desirable to reconfirm the consistency between location information and meteorological data before proceeding to business feasibility decisions or detailed design.

Step 5: Checklist of Items to Verify After Input

When you create a site and link meteorological data, check the inputs before running the simulation. In PVSyst, because there are many configuration items, you can sometimes proceed to panel settings, loss settings, and layout settings without noticing mistakes in the site configuration. Even if you later notice that the generated energy is anomalous, it takes time to determine whether the cause lies in the site settings or the equipment conditions. Therefore, it is important to make a habit of checking at the initial stage.

The first thing to check is whether the latitude and longitude positions are correct. After entering the numbers, if there is a map display or a location information confirmation screen, verify that the candidate location matches. Entering latitude and longitude in reverse, getting the signs wrong, or misplacing the decimal point can result in a completely different area. If a project in Japan shows a point overseas, appears in an unnatural place such as out at sea or in the mountains, or is far from the intended site, it must be corrected immediately.

Next, verify whether the elevation matches the actual conditions of the candidate site. If the elevation is extremely high or low, the input units or the reference point used may be incorrect. Elevation may not appear to have a large direct effect on simulation results, but it is an important element indicating the consistency of the site information. In particular, in mountainous or sloped areas, recording which elevation within the site was adopted will make it easier to explain later.

For meteorological data, check the distance from the site, regional characteristics, and monthly trends. Even data that are geographically close to a candidate site can be inappropriate if they come from the far side of a mountain or from an area with a different climate. Verify that the monthly patterns of solar radiation and temperature do not differ significantly from the candidate site's typical climate. In practice, it is important not only to look at the final power generation figure but also to assess the validity of the meteorological conditions on which it is based.

Additionally, check that site names within the project are not being confused with weather data names. When multiple candidate sites are being considered simultaneously, mistakes are likely to occur — for example, weather data for site B being linked to site A’s project, locations from past projects remaining, or forgetting to change the site settings in a duplicated project. When duplicating a project to create condition variants, always verify that the site settings have been correctly carried over or have been changed to the intended site.

Finally, as an initial verification of the simulation results, examine not only the annual generation but also the monthly generation trends. If there are problems with the site or meteorological data, anomalies can appear in the monthly generation pattern. For example, if seasonal variations are extremely unnatural or the output trend does not match the expected climate of the region, review not only the equipment conditions but also the site settings. It is important not to judge solely by whether the generation figures are high or low, but to confirm that the results are reasonable given the site conditions.

Common Mistakes When Setting Locations and How to Fix Them

One common mistake in PVSyst site settings is using the representative point from the address as-is. The position obtained from an address may indicate the site entrance, an existing building, a management reference point, or similar, and can be offset from the actual area where panels will be installed. While this may have little impact on small projects, for ground-mounted systems or large sites using a point far from the center of the generation area can lead to incorrect assumptions about elevation and the surrounding environment. As a countermeasure, check the site map and layout plan in addition to the address, determine a representative point for the generation equipment, and then obtain the latitude and longitude.

Another common mistake is getting the latitude and longitude format wrong. Examples include entering degrees-minutes-seconds values directly into a decimal input field, mis-handling the sign for north latitude and east longitude, or dropping too many decimal places. Errors in entering location information may not be immediately noticeable on the screen. As a countermeasure, always check the position on the map and the place name after input to see whether they match the intended location. Don’t judge correctness based only on the numbers; make a habit of verifying visually as well — it’s safer.

Care must also be taken in handling elevation. If there are differences in elevation within the site, you may be unsure which elevation to use. There are several candidate points, such as the lowest point, the highest point, near the entrance, or the center of the panel layout area. As a countermeasure, choose a representative value that matches the purpose of the simulation. At the stage of comparing candidate sites, a rough representative elevation may be acceptable, but as you approach detailed design, be mindful of the elevations within the actual area where the power generation equipment will be installed. If necessary, check multiple points within the site and adopt an average or other representative value.

Mistakes in selecting meteorological data are also common. Just because a site is nearby does not necessarily mean the meteorological conditions are similar. Mountainous and flat areas, inland and coastal locations, and basins versus open regions can have different conditions even at short distances. To address this, check not only distance but also terrain and climatic characteristics. Especially when using the data for business feasibility assessments, make sure you can explain the reasons for selecting the meteorological data.

Also, be careful about leftover settings when duplicating a project. If you copy a project from a past case or from another candidate site to start a new evaluation, the location name and weather data may remain as they were. If you change only the equipment conditions and run the simulation, you might end up using results calculated under the conditions of a different site. As a countermeasure, immediately after duplicating a project, check the location, weather data, time zone, elevation, and project name together.

Approaches to Streamlining Point Setting in Professional Practice

When using PVSyst in practice, thinking through site settings on the spot each time is time-consuming. The more projects you handle, the more important it becomes to standardize input rules and verification procedures. In particular, when the person who compares candidate sites, the person who enters design conditions, and the person who reviews the results are different, failing to share a common approach to site settings will cause assumptions to vary from project to project.

First, it's efficient to create a standardized format for organizing candidate site information. Record the project name, candidate site name, address, approach to determining the representative point, latitude, longitude, elevation, date obtained, reviewer, and the rationale for selecting meteorological data in a consistent format. This makes it easier to ensure that the settings in PVSyst match the assumptions in internal documents. When reviewing simulation results later, you can quickly verify the basis for the site settings.

Next, it is important to consider differentiating the required level of precision by stage for candidate sites. In initial screening, candidates may be compared based on their approximate locations and general meteorological conditions. At this stage, priority is given to comparing multiple candidates in a short time. By contrast, when progressing to feasibility assessments or design studies, representative points, elevation, meteorological data, surrounding shading, and site development conditions need to be checked more carefully. Requiring the same level of precision at every stage makes the work too burdensome, so it is more efficient to vary the verification level according to the stage of review.

Also, when sharing location settings with the team, it is important to verbalize the decision criteria. For example, define rules such as using the center of the panel placement area as the representative point for ground-mounted installations, using the center of the target building as the representative point for rooftop installations, and dividing large sites into multiple areas for consideration as needed; doing so reduces variability among personnel.

When using PVSyst, it is not enough to just learn the screen operations; organizing which assumptions to check and when to check them contributes to practical competence. Site settings are simple as numerical input, but because they affect the overall reliability of the energy yield simulation, it is worth performing them carefully at the outset. The more you streamline your work, the more important it is to create mechanisms that make checks easy, rather than omitting them.

Enhance design accuracy by leveraging on-site positioning data

When setting the location in PVSyst, in initial studies it is common to use latitude, longitude, and elevation obtained from desk-based sources, but as the project progresses, accurate on-site location information becomes important. Especially for ground-mounted PV plants, accurately understanding site boundaries, panel layout areas, equipment installation locations, roads, slopes, and surrounding structures can reduce discrepancies between simulation conditions and actual site conditions.

The benefits of using on-site location information go beyond merely setting points. It also informs panel layout, site development planning, shadow checks, drainage planning, maintenance access routes, and staking out positions during construction. For example, rather than only defining a representative point for a candidate site at the desk, if you geolocate the approximate center of the power generation equipment and the main boundary points on the actual site, you can make the assumptions in PVSyst more realistic.

Also, at solar power plants, slight elevation differences across the site and nearby obstacles can affect the design. On former forest land, reclaimed land, land converted from agricultural use, and sloping terrain, undulations and obstacles that are difficult to discern on maps may be present on site. By acquiring high-precision location information on site and, when necessary, combining it with point clouds and photographic records, it becomes easier to verify the design assumptions.

A useful tool in such situations is LRTK, a GNSS high-precision positioning device that can be attached to and used with an iPhone. Using LRTK makes it easier to record, with high precision, on-site position information such as representative points of candidate sites, locations near boundaries, and reference points for equipment placement. By accurately identifying on-site positions before and after performing desktop simulations in PVSyst, the relationship between point setting, layout planning, and pre-construction verification becomes clear.

PVSyst is an important software for evaluating power generation and losses, but in practice the question of how to independently verify the accuracy of the site information and on-site conditions entered remains a challenge. By combining on-site positioning tools such as LRTK, it becomes easier to link desk-based power generation simulations with actual field measurements, enabling consistent use of location information from site selection through design, construction, and operation and maintenance.

Summary

Setting a site in PVSyst is not simply the act of entering a place name or coordinates on the screen. It is a series of steps: organizing the basic information of candidate sites, selecting a representative point, confirming latitude, longitude, and elevation, creating the site in PVSyst, linking it to meteorological data, and verifying consistency after input. When the site is set appropriately, the prerequisites for subsequent panel configuration, PCS configuration, loss settings, shading settings, and layout studies become stable.

Especially in practical work, it is important to be able to explain the rationale for site selection. If you document which location within the candidate sites you used as the representative point, how you verified the latitude, longitude, and elevation, and why you chose the meteorological data, you can enhance the reliability of the simulation results. Conversely, if the site selection remains vague, it becomes difficult to explain the assumptions behind any power generation figures.

When learning how to use PVSyst, it is important not only to follow the workflow of the interface but also to understand the meaning of the information you enter. Because site/location settings are the initial step, carefully setting conditions here can reduce rework in later stages. In the early phase of selecting candidate sites, compare efficiently, and when progressing to detailed analysis, verify representative points and on-site conditions more accurately—be mindful of adapting your approach to the stage of evaluation.

Furthermore, by utilizing high-precision position information obtained on site, you can bring the point settings in PVSyst closer to the actual site conditions. Using LRTK, an iPhone-mounted GNSS high-precision positioning device, makes it easier to record on-site representative points of candidate sites, boundaries, and reference points for equipment layout, and helps verify the assumptions used in simulations. By combining PVSyst’s power generation assessments with on-site high-precision positioning using LRTK, it becomes easier to carry out practical work based on more reliable positional information—from candidate site selection through design, construction, and operation and maintenance of solar power plants.