What can you do with PVSyst? How to use it and its basic features, organized into 6 items

Table of Contents

• What is PVSyst

• Basic Function 1: Setting Installation Conditions and Meteorological Conditions

• Basic Function 2: Setting the System Configuration

• Basic Function 3: Array Layout and Azimuth/Tilt Considerations

• Basic Function 4: Evaluation of Shading and Losses

• Basic Function 5: Power Generation Simulation and Results Verification

• Basic Function 6: Case Comparison and Design Improvement

• Basic Workflow for Using PVSyst

• Practical Points to Note When Using PVSyst

• Summary

What is PVSyst?

PVSyst is simulation software for predicting the energy yield of photovoltaic systems and for comparing differences under various design conditions. Rather than merely roughly calculating annual generation, a major feature is that it enables you to build up factors such as the site’s meteorological conditions, the system’s orientation and tilt, DC- and AC-side configurations, shading effects, and losses due to wiring and temperature, and to verify the resulting output and generation forecast.

Practical uses of PVSyst are wide-ranging, including preliminary rough estimates, comparisons of multiple proposals, creating supporting evidence for internal presentations, pre-construction feasibility checks, and preparing benchmarks for operational planning. For example, even for a plan with the same capacity, you can quantitatively see how much the energy yield and losses differ when you slightly change the installation angle, widen the row spacing, or size the DC side somewhat larger. Because you can compare numbers rather than relying on intuition, it is easier to improve the quality of decision-making.

On the other hand, PVSyst is not software that will magically give you the right answer. If the input conditions are coarse, the results will be coarse, and if the local terrain and surrounding obstacles are not adequately reflected, there will be differences from actual power generation. Therefore, when using PVSyst, it is important to understand not only "what can be calculated" but also "what assumptions should be entered carefully." Rather than memorizing functions in detail at first, grasping which items affect the results is the quickest route to improvement for beginners.

Basic Function 1: Setting Installation Conditions and Weather Conditions

The first important task in PVSyst is setting the installation conditions and the meteorological conditions. By installation conditions we mean the planned site's location, altitude, the appearance of the surrounding terrain, and the directional conditions that form the premise for receiving sunlight. Meteorological conditions are the environmental information that forms the basis of power generation, such as annual solar irradiation, ambient air temperature, and wind conditions when required.

This setting is important because the output of a solar power system is not determined by the equipment alone. Annual generation differs between areas with high and low solar irradiance, and regions with higher temperatures are more susceptible to output losses associated with temperature increases. Furthermore, at sites where morning and evening sunlight is reduced by mountain ridgelines or nearby buildings, outcomes can vary significantly even with the same orientation and the same capacity.

A common mistake when using PVSyst is to stop after setting the site location and feel reassured. However, in practice it is essential to verify whether the meteorological data you are using closely represents the actual site, whether terrain-related horizon/visibility conditions are reflected, and whether elevation differences or local climatic variations are being ignored. In particular, mountainous areas, coastal zones, snowy regions, and basins are prone to errors if you simply apply representative values from nearby stations.

At the beginner stage, it’s easier to stay organized if you proceed in this order: first set the planned site correctly, then check the consistency between annual solar irradiance and ambient air temperature, and, if necessary, examine the effects of the horizon and nearby shading. When considering what can be done with PVSyst, the configuration of these meteorological conditions is the entry point for all calculations. If this is unclear, you should bear in mind that no matter how thoroughly you refine the equipment parameters afterward, the overall accuracy is unlikely to improve.

Basic Function 2: System Configuration Settings

Next, you should focus on the system configuration settings. Here you decide the backbone of the installation: what DC capacity to choose, how to arrange the AC-side combiner/collector, how many modules to connect as a single string, and how to divide multiple circuits. Based on these configuration parameters, PVSyst can evaluate voltage ranges, how loads are applied, and whether output clipping is likely to occur.

One of the things practitioners care about most when using PVSyst is the balance between the DC side and the AC side. If you size the DC side larger, you may be able to capture more output during periods of low irradiance, but under strong irradiance conditions the AC side can become the limiting factor. Conversely, allowing too much headroom can be disadvantageous in terms of equipment utilization and investment efficiency. A benefit of PVSyst is that it makes it easy to see how this kind of design balance is reflected in annual energy production and losses.

Also, even with the same capacity, if the way connections are arranged is improper the system is more likely to fall outside the expected operating range. Being able to identify in advance points that are easy to overlook on paper—such as voltage rise at low temperatures, voltage drop at high temperatures, and imbalances between circuits—provides great value during the design phase. Beginners tend to focus on filling in parameters on the screen one by one, but what really matters is having a design intent: why you choose that configuration.

From a functional perspective, the system configuration settings in PVSyst can be described as a feature that checks whether the planned installation is configured in a feasible way. Instead of determining capacity based only on intuition, the overall system connectivity can be verified numerically, leading to a design that requires fewer revisions.

Basic Function 3: Consideration of Array Layout, Azimuth, and Tilt

An indispensable basic function of PVSyst is its tools for examining array layout, orientation, and tilt. In solar power generation, even with the same equipment, the direction the modules face, the angle of inclination, and the spacing between rows can greatly change both energy output and shading patterns. PVSyst can incorporate these differences in installation conditions into its simulations.

For example, the optimal solution varies depending on whether you want to maximize generation by orienting panels southward or prioritize installed capacity and temporal dispersion with an east–west layout. For rooftop projects, the question is whether to take advantage of the existing roof pitch or adjust the tilt with racking, and for ground‑mounted installations, the trade‑offs involving land shape and row spacing are important. In understanding how to use PVSyst, it is essential not to simply enter a single angle and stop, but to compare multiple conditions and make a judgment.

Furthermore, row spacing settings affect not only power output but also land-use efficiency. Widening the spacing can be expected to reduce mutual shading, but the amount of equipment that can be installed on the same site may decrease. Conversely, packing them too tightly can increase shading in the mornings, evenings, and during winter, which can impact annual results. In PVSyst, you can numerically compare these layout differences and evaluate where to strike the right balance.

An easy-to-understand approach for beginners is to first create a single realistic layout, and then prepare comparison cases that change only one of orientation, tilt, or row spacing. If you change many conditions at once, you won’t be able to tell which element caused the differences in the results. It’s easiest to grasp what PVSyst can do when you narrow the variables for comparison in this way. This makes it easier to see where design improvements are possible and to find a compromise that fits the site conditions.

Basic Function 4: Evaluation of Shading and Losses

What greatly enhances PVSyst's value is its shading and loss assessment capability. In PV system design, the presence of sunlight does not mean power will be generated as-is. If shading occurs due to surrounding buildings, trees, terrain, or insufficient spacing between equipment, the incident irradiance decreases. Furthermore, there are multiple factors that reduce generation, such as temperature rise, wiring resistance, soiling, component variability, and conversion losses. PVSyst is useful in practice because it allows you to review the overall picture while organizing these losses by category.

In assessing shadows, it is important to distinguish between shadows that affect sunrise and sunset—such as those from distant mountain ranges—and shadows caused by nearby equipment or structures. The former affects the hours of sunlight received in the morning and evening, while the latter produces localized losses that vary by time of day and season. When you are not yet familiar with using PVSyst, you may be inclined to think of shadows simply as present or absent, but in reality you need to determine when, to what extent, and which array(s) are affected.

The same applies to loss settings. For example, underestimating losses from soiling can produce results that are far from reality in arid regions or in locations with heavy traffic. Conversely, estimating every loss conservatively may be safe but can make an assessment of project viability unduly harsh. To correctly understand what PVSyst can do, you should not view losses as a single number; instead, you need the perspective to identify which losses are dominant and where there is room for improvement.

This feature is not only useful for improving design accuracy but also effective for explaining things to stakeholders. Because it can show, step by step, why the energy production reaches a given value—from solar irradiance to the final output—it is easier to gain acceptance than by merely presenting the results. Even beginners can deepen their use of PVSyst simply by developing the habit of carefully reviewing the shading and loss items.

Basic Function 5 Power Generation Simulation and Result Verification

The most immediately recognizable feature of PVSyst is the power generation simulation itself. Based on the specified meteorological conditions, system configuration, layout conditions, and loss assumptions, you can check annual energy production, monthly energy production, specific yield, performance indicators, and breakdowns of various losses. When practitioners are asked, "What can PVSyst do?", this is likely the first thing that comes to mind.

However, what is important when checking the results is not to stop at the annual power generation figure. For example, even if the annual values are similar, a proposal that is strong in summer and one that is strong in winter have different operational implications. If the output tendency by time of day differs, compatibility with grid conditions and loads may also change. Furthermore, by looking at the breakdown of losses, the direction for improvement becomes clear—whether shadows are having an effect, whether temperature has a large impact, or whether conversion saturation is becoming noticeable.

A recommended way to use PVSyst is: when you open the results screen, first check the overall consistency, then review the monthly trends, and finally examine the breakdown of losses. If you jump straight into detailed graphs, it becomes hard to tell what is abnormal and what is within expectations. For example, if generation is unusually low in a particular month, that can be a clue to suspect errors in shading or weather condition settings, and if any loss item is larger than expected, it becomes a candidate for design changes.

The essence of this feature is not merely to display calculation results, but to provide material for interpreting the quality of a design. To master PVSyst is not to simply accept results, but to use those results to inform your next decisions. Rather than stopping at the numbers, by tracing why they occurred you enhance both the accuracy of your design and your ability to explain it.

Basic Function 6 Case Comparison and Design Improvement

What is especially useful in practical work with PVSyst is using it to compare multiple cases to improve the design. In real projects, it is often not possible to finalize a single proposal from the outset. There are multiple choices—what orientation to use, what tilt angle to set, how much inter-row spacing to provide, how large to size the DC side, and so on—and each option differs in energy production, constructability, site efficiency, and operability.

PVSyst is well suited to numerically compare the differences between such options and to identify directions for design improvement. For example, it can clarify points that are often discussed by intuition, such as how much annual energy production increases or decreases with a slight change in tilt angle, whether the reduction in shading or the decrease in installed capacity wins out when row spacing is widened, and how much clipping losses increase when the DC side is oversized.

What matters here is to make the purpose of the comparison clear. The evaluation criteria change depending on whether you aim solely to maximize annual energy production, prioritize total output within a limited area, or consider factors such as ease of construction and maintainability. When you are not yet familiar with how to use PVSyst, you may be tempted to run many different scenarios, but if your objective is unclear, it will be harder to make use of the comparison results.

For beginners, the recommended approach is to pick a single baseline case and then perform sequential comparisons in which you change only one item at a time. For example, first change only the orientation, next change only the tilt, and then change only the row spacing. This makes it easier to grasp how much each condition affected the outcome and produces materials that are easy to use for internal presentations and decision-making. You will most readily appreciate what PVSyst can do when you advance the design using this comparison feature.

Basic workflow for using PVSyst

So far we have organized the functions into six items, but when actually using PVSyst, keeping the workflow in mind makes it less likely to get confused. The basic sequence is: decide the site, check the meteorological conditions, configure the system, enter the layout conditions, set losses and shading, read the calculation results, and, if necessary, create comparison scenarios. Simply proceeding without breaking this flow will give even beginners a much clearer outlook on the work.

In the initial stage, it is important not to try to build a perfect model all at once. First, develop a baseline case under standard conditions and make sure the entire model can be calculated without issues. Then, incorporate site-specific conditions one by one; this makes it easier to track where the results changed. Especially when you are unfamiliar with using PVSyst, including too many minor losses and complex shading conditions from the start will make it difficult to isolate the causes.

Also, at each milestone of the work, it is useful to check whether you can explain in words the assumptions you entered. If you can explain why this orientation, why this tilt, and why this loss rate, then those settings can be said to be organized as design decisions rather than mere data entry. Conversely, if there are many items you cannot explain, it may be that you have only entered numbers into the software and it is not yet a design.

PVSyst is powerful and convenient once you become familiar with it, but what beginners should focus on first is not trying out a wide range of complex features; it is correctly completing the sequence of calculations while preserving the basic workflow. By accumulating that experience, the way you compare cases, interpret results, and link them to site conditions will naturally improve.

Practical considerations to keep in mind when using PVSyst

When using PVSyst, be careful not to place too much trust in the simulation results. No matter how well-organized the outputs appear, if the assumptions are far removed from the actual site conditions, the figures will be difficult to use in practice. Particular points to watch are the representativeness of the meteorological conditions, omissions in reflecting obstacles and terrain, discrepancies with the actual installable area, and overly dense layouts that do not take maintenance requirements into account. Plans that may work on paper often fail to hold up in the field.

Also, it is important to be aware that beginners are especially likely to use default values as-is. Defaults are convenient as a starting point, but they are not necessarily appropriate to adopt without change. Soiling, temperature, wiring, component variances, and installation quality differ from project to project and can also vary by region and site conditions. What makes the difference in how PVSyst is used is whether you avoid uncritically accepting these defaults and reassess their validity for each project.

Moreover, it is important not only to compare the numerical results, but to cultivate the habit of understanding why the differences arose. Even if a proposal shows a slightly higher annual energy production, if its loss structure is unrealistic, operational uncertainty may increase. Conversely, a proposal with slightly lower generation but smaller impacts from shading and temperature and greater stability may be easier to manage in practice. To truly make the most of what PVSyst can do, it is essential to understand what the numbers mean, not just their magnitude.

Another important point is not to separate simulations from on-site measurements. Even if a design looks optimal on paper during the planning stage, if you do not fully grasp the actual terrain, elevation differences, installation clearances, and distances from surrounding structures, plan revisions will occur in later stages. In other words, improving the accuracy of PVSyst requires, as a prerequisite, accurately understanding the on-site dimensions and positional relationships rather than trying to do everything inside the software.

Summary

When organized into six items, what PVSyst can do is: setting installation conditions and meteorological conditions, setting the system configuration, considering array layout and azimuth and tilt, evaluating shading and losses, simulating energy production and checking results, and improving designs by comparing cases. In other words, PVSyst is not just software for calculating energy production; it is a practical tool for organizing design conditions, comparing multiple proposals, and providing numerical justification for decisions.

When using PVSyst, the key is less about comprehensively memorizing every feature and more about systematically organizing the assumptions that affect the results. Pin down the location and weather, set up the system configuration, check the layout and shading, analyze the composition of losses, and improve through comparisons. If you stick to these basics, even beginners can connect it to practical work.

And the more you aim for higher-precision simulations, the more important it becomes to accurately grasp on-site positions, elevations, and separation conditions. If you want to efficiently carry out pre-design site surveys and position checks before and after construction, it is effective to review even the means of on-site measurement. LRTK, as an iPhone-mounted GNSS high-precision positioning device, makes it easy to smoothly acquire site coordinates and verify positions, linking the flow from organizing simulation assumptions through construction and confirmation. The more practitioners seek to improve the accuracy of desktop analyses, the more important it is to pay attention to how on-site data are collected alongside the use of design software.