Don't Get Lost Using PVSyst｜12 Essential Basic Operations for Practical Work

Table of Contents

• Grasp the overall workflow first

• Operation 1: Clarify objectives and prerequisites

• Operation 2: Align the project's baseline conditions

• Operation 3: Set the meteorological conditions appropriately

• Operation 4: Determine the installation azimuth and tilt

• Operation 5: Input the array configuration

• Operation 6: Confirm loss parameters and equipment conditions

• Operation 7: Model the effects of shading

• Operation 8: Adapt the mounting method and temperature conditions to the site

• Operation 9: Run the simulation and verify consistency

• Operation 10: Interpret monthly results and the breakdown of losses

• Operation 11: Compare multiple options to create decision-making materials

• Operation 12: Organize as reporting materials

• Connect analysis results to on-site verification

• Summary

Begin by getting an overview of how to use it

The basic workflow for this type of power generation simulation software is to decide the assumptions, enter the equipment parameters, reflect loss factors, run the analysis, and compare the results. A common pitfall is trying to enter data in the order it appears on the screen. In practice, it's more effective to determine the input order based on the logical sequence of the study rather than the screen. First decide the location, capacity, installation type, and expected outputs, then proceed to meteorology, azimuth, tilt, circuit configuration, and loss conditions, and finally review the results to verify their plausibility.

What is especially important is to understand that entering numbers and setting assumptions are separate actions. For example, if you rush to produce the annual power generation and look only at the results while leaving tentative weather conditions and rough shading assumptions in place, the evaluation will change the moment you later revise those assumptions. An analysis that is useful in practice is not one in which numbers are simply produced, but one in which you can explain the relationship between assumptions and results. Therefore, the key to using the tool is not merely memorizing the操作, but proceeding while understanding which inputs have a strong effect on the results.

Operation 1: Clarify the objectives and prerequisites

The first action should not be to open the software, but to put into words what you are analyzing in order to make a decision. Whether you're doing a preliminary estimate for a new project, comparing multiple options, or preparing explanatory materials for internal approval will affect both the required level of accuracy and the depth of input. If you start work while the objective is unclear, you may end up spending time configuring things in more detail than necessary or, conversely, omitting important items.

The assumptions to be clarified here are the installation site, the assumed capacity, the conditions of the installation surface, the presence or absence of surrounding shading, the approach to connection and operation, and the metrics you want to evaluate. For example, the results you should look at differ depending on whether you only need annual energy production, want to examine monthly variability, or need to explain the breakdown of losses. Also, rooftop projects and ground-mounted projects tend to differ in temperature conditions and in how inter-row shading is handled, so clarifying assumptions at an early stage reduces rework in later stages.

In practice, simply summarizing the assumptions on a separate sheet or memo before beginning data entry will improve work efficiency. When there are multiple conditions to consider, it is important to decide in advance which factors to hold constant and which to use as comparison items. If this is unclear, then when you compare proposals later you won’t be able to tell whether the differences are due to orientation, capacity, or loss settings. The initial organization may be unglamorous, but it is the single most effective step to prevent mistakes.

Operation 2 Standardize the project's baseline conditions

The next step is to align the baseline conditions that will be common across the entire project. By standardizing the conditions that form the foundation of the overall analysis—such as location and elevation, the assumed evaluation period, the units of output, the approach to capacity, and the treatment of area—you enable correct comparisons later. If these standards fluctuate, when the same case is handled by a different person the results will not align, making internal explanations difficult.

A common occurrence in practice is having discussions without standardizing the definition of capacity. Because similar-sounding terms—equipment capacity, connection capacity, assumed output for design, etc.—have different meanings, it is necessary to clarify which figure is being used as the reference. Also, whether the assessment is annual or a check of behavior in a specific month changes how the results are interpreted. At the initial setup stage, it is important to align on what will be treated as the reference value.

Additionally, deciding on naming conventions for files and proposals can be surprisingly effective. In practice, the more design options you have to consider, the harder it becomes to tell which conditions are included in each file. If you manage project names, orientation, slope, capacity, dates, and so on according to a consistent set of rules, it will be easier to compare and revise them later. How to use the software is not complete if it only covers the user interface; only by including these management practices does it become truly practical for real-world work.

Step 3: Set Weather Conditions Appropriately

In power generation simulations, meteorological conditions are among the most important inputs. If solar irradiance, temperature, and wind conditions are not appropriate, no matter how carefully you input equipment parameters, the reliability of the results will not improve. Beginners tend to focus on equipment-side settings, but in practice the selection of meteorological conditions is the item that should be treated most cautiously from the outset.

What is important here is not mechanically selecting the conditions that are closest to the site, but judging how well that data represents the actual situation of the project. Differences in terrain, whether the site is coastal or inland, elevation changes, the presence or absence of snow cover, and the tendency for fog or cloudiness can alter the power generation environment even within the same region. Therefore, once you have chosen the available meteorological conditions, always check for monthly trends or any extreme biases, and confirm that they do not diverge from the local on-the-ground perspective.

In practice, you don't decide the meteorological conditions once and then be done. It's realistic to use representative conditions at the preliminary/estimate stage and shift toward more site-specific conditions for detailed studies. Rather than aiming for perfection from the outset, it's more efficient to increase the accuracy of the conditions according to the stage of the study. What matters is documenting which meteorological conditions were used together with the results so they can be explained later.

Operation 4: Determine the installation azimuth and tilt

Basic operations that readily affect power generation include setting the installation azimuth and tilt. If you enter values based only on ideal conditions, the results tend to deviate significantly from the actual site or roof conditions, so site-specific inputs are necessary. In practice, decisions are made not only by pursuing the angle that maximizes power generation but by balancing racking conditions, roof pitch, spacing, constructability, and maintainability.

Beginners often fall into the trap of treating orientation and tilt as mere numerical inputs. In reality, changing the orientation alone can determine whether it favors the morning or the afternoon, and changing the tilt alters the balance of generation across seasons. Therefore, you need to decide conditions while being mindful not only of the annual total but also of monthly and time-of-day biases.

Also, for projects with multiple installation surfaces, it is important not to represent the whole by a single orientation and tilt, but to consider surfaces with differing conditions separately. In particular, roof projects often have different conditions on the north–south and east–west faces, and oversimplifying can lead to a divergence from reality. First create a representative plan, and then, if necessary, reflect the differences between surfaces so you can better balance accuracy and workload.

Operation 5 Enter the array configuration

Next, an important item is entering the array configuration. Here you must decide how many modules to arrange and in what layout, how to approach series and parallel connections, and how to summarize the overall system configuration. In practice, this operation affects not only the power generation but also whether the system ends up somewhat oversized or is designed with sufficient margin.

What you need to be mindful of here is not simply cramming in the maximum number of units, but balancing electrical viability with layout consistency. Even if something appears to fit the installation area in theory, there are cases where it becomes unworkable once you account for maintenance access routes, edge clearances, shadowing, and cable routing. Conversely, being overly cautious can lead to underestimating the amount that can be installed. Therefore, configuration input should proceed not as a desk-based capacity calculation but with verification that it is reasonable from both placement and operational perspectives.

Also, even with the same capacity, the way components are arranged can change how losses occur and the operating range. Therefore, rather than drawing conclusions from a single configuration, it is practical to try and compare multiple arrangements within a similar capacity band. Configuration input may seem unremarkable at first glance, but it is an important step that directly affects not only differences in power generation but also whether the design is easy to explain.

Operation 6 Confirm loss conditions and equipment conditions

Confirming loss factors and equipment conditions is essential to bring analysis results closer to reality. Ideal solar irradiation does not directly translate into generated electrical energy; energy is reduced by various factors such as temperature rise, wiring, conversion losses, soiling, aging, and downtime. To make the analysis reliable in practice, it is important not to inflate the estimated generation but to be able to explain the results after incorporating reasonable losses.

What you should be careful about here is not to keep reusing common default initial values as they are. Depending on the project, susceptibility to soiling, the quality of ventilation, cable length, maintenance arrangements, and assumptions about output curtailment will vary. Since expected losses change when environmental conditions differ—such as rooftop, ground-mounted, near farmland, coastal areas, or locations with high dust—the settings need to be tailored to the actual site conditions.

On the other hand, spending too much time estimating every loss in detail is also inefficient. For rough estimates, it is practical to use representative values and then refine the important items during the detailed stage. The key is to clarify which losses should be treated as fixed values and which should be reviewed on a case-by-case basis. When you can handle loss conditions carefully, the credibility of the analysis results improves noticeably.

Operation 7 Modeling the Effects of Shadows

The impact of shading is one of the factors in power generation simulations that most often causes differences in results. On site there are various shading elements, such as surrounding buildings, trees, fences, terrain undulations, and shadows between rows of equipment. If shading is overlooked, power generation is easily overestimated; conversely, if shading is overestimated, the results become unnecessarily conservative. Therefore, modeling that reflects the actual site conditions is important.

The key here is to discern what can be simplified and what must not be omitted. In projects where the influence of distant topography is dominant and projects where nearby obstructions have a large impact, the elements that should be prioritized for modeling differ. Also, because shadows are not constant throughout the year and their appearance changes with season and time of day, it is important to determine whether they have a large effect only during winter mornings and evenings or whether they affect conditions year‑round.

Shadow condition inputs are highly dependent on the accuracy of on-site understanding. Because height relationships that are hard to interpret from drawings and actual obstacles can be easily overlooked, it is desirable, if possible, to combine them with on-site verification. Shadow settings on the analysis screen are merely a depiction of the site, and if you consider that the quality of on-site information directly affects the quality of the results, the importance of shadow modeling becomes clear.

Operation 8 Adapt the installation method and temperature conditions to match the site

Even under the same solar irradiance conditions, the tendency for temperature rise changes depending on the installation method, resulting in differences in power generation. Differences such as whether the array is closely attached to the roof, whether ventilation can be provided at the rear, or whether wind can pass through easily in ground-mounted installations are easily overlooked, yet they certainly affect annual power generation. Therefore, temperature conditions are not merely a supplementary item; in practice they are a basic check that should always be performed.

Especially, if representative conditions from the preliminary estimate phase are carried unchanged through to detailed design, projected temperature losses can be off. This is because, as the layout becomes more concrete, the number of items that should be reviewed—installation height, row spacing, rear clearance, surrounding thermal environment, etc.—increases. When site conditions become clearer, reconciling the installation method with the temperature conditions can further improve the accuracy of the analysis.

Also, temperature conditions are easier to understand when considered together with heat-loss and shading conditions rather than viewed in isolation. For example, in poorly ventilated locations temperature losses tend to increase, and in areas with significant shading the temperature behavior also changes depending on the time of day. When you can set these relationships consciously, the analysis shifts from mere software operation to design decisions that reflect on-site conditions.

Operation 9 Run the simulation and verify consistency

Once you enter the required conditions, execute the analysis. However, what matters here is to check for any inconsistencies or oddities in the inputs and the calculation results before focusing on the output. If you feel reassured merely because numbers have been produced, the discussion may proceed on incorrect assumptions. In practice, it is important to treat the initial run not as deliverable production but as a consistency check.

What to check is whether the generation is excessively high or low relative to capacity, whether the month-by-month trend does not deviate significantly from what you would expect given the weather, whether there are any unnatural spikes in the breakdown of losses, and whether the effects of shading or temperature have not reversed compared with expectations. Even if no error messages appear, it is not uncommon for mistaken inputs or misunderstandings of units to produce unrealistic results.

Also, it is practical to treat the initial result not as definitive but as a starting point for spotting anomalies. By slightly changing the conditions to check sensitivity, you can see which factors most strongly affect the results. Once you develop this intuition, both the speed of analysis and the ability to explain findings will improve significantly. Pressing the run button itself is easy, but the subsequent consistency checks are where the practitioner’s skill really shows.

Operation 10 Interpreting Monthly Results and Loss Breakdown

After the analysis is complete, many people first look at the annual power generation. Of course that's an important indicator, but on its own it is insufficient as a basis for judgment. What is required in practice is the ability to explain why that result occurred. To do this, you need to interpret the monthly results and the breakdown of losses, and understand seasonal variation and the structure of the losses.

Looking at monthly results makes the effects of tilt and azimuth, the reductions due to high temperatures in summer, and the impacts of shading in winter easier to see. Even if annual totals are similar, designs with large monthly imbalances and those that are stable can be used or evaluated differently. Also, by examining the breakdown of losses you can see which factors are dominant: whether shading is the main issue, temperatures are the larger factor, or wiring and conversion losses are heavier than assumed — once identified, the direction for improvement becomes clear.

The important point here is the order in which you read the results. If you first look at the annual total, then the monthly trend, and finally the breakdown of losses, it becomes easier to connect the overall picture with the causes. Rather than simply listing numbers, being able to explain the context behind the results will make your internal reports and customer explanations more persuasive. No longer being unsure about how to use it does not mean becoming accustomed to the input; it means being able to explain the meaning of the results in your own words.

Step 11: Create decision-making materials by comparing multiple options

More useful in practice than refining a single proposal is organizing decision-making material by comparing multiple proposals. By slightly varying conditions—such as changing the installation orientation, changing the tilt, changing the row spacing, or changing the capacity allocation—and comparing the results, the design’s degrees of freedom and constraints become apparent. A standalone proposal without comparisons, even if it includes numbers, is often weak for decision-making.

When making comparisons, the important thing is to narrow down the items you change. If you change many conditions at once, you will not be able to tell what caused the differences. For example, if you want to see the effect of orientation, fix the other conditions; if you want to see the effect of shading conditions, align the orientation and capacity. This makes the analysis results not just a string of numbers but a basis for judgment.

Also, comparing multiple design options is useful not only for design optimization but also for accountability. To show why a particular option was chosen, comparison with other options is indispensable. Looking comprehensively—not only at power generation but also at installable capacity, operational stability, susceptibility to shading, temperature conditions, and constructability—reveals a realistic option. Once you become familiar with the software, it is important to move beyond creating a single design and consciously pursue comparative designs.

Operation 12: Organize as reporting materials

Analysis is only half complete when results are produced. In practice, those results become valuable only when they are organized in a form that third parties can understand. Internal approvers, sales representatives, construction personnel, and clients want different information depending on who they are, but what is commonly required is that the assumptions, key inputs, summary of results, and points to note are compiled in a consistent format.

When preparing reporting materials, you should not emphasize only the annual energy production; you must always include the conditions under which it was calculated. If meteorological conditions, installation orientation, tilt, treatment of shading, and assumptions about losses are omitted, later comparisons become impossible and reproducibility is lost. Also, depending on whether the project is at the study stage or close to final design, the way figures are handled needs to change. It is very important in practice not to present estimated values as if they were final.

Moreover, it is important that reports be structured in an order that makes it easy for readers to make judgments, rather than being a mere listing of results. Organizing them in the order of assumptions, analysis conditions, main results, comparison points, and conclusions makes them easier for non-experts to understand. Improving how you use the software is not about completing everything within the software, but about being able to connect analysis results to business decision-making.

Connect analysis results to on-site verification

Power generation simulations cannot be completed solely on a screen. In real-world practice, factors that cannot be determined from drawings or satellite images alone—relative heights, obstacles, incorrect assumptions, delivery routes, and the effects of the surrounding environment—can influence the results. To further increase the accuracy of the analysis, it is essential to verify the desk-based conditions on site and, when necessary, return to the inputs.

What helps in such situations is a system that can quickly collect on-site location information and point records. Using smartphone-mounted high-precision GNSS positioning devices like LRTK makes it easier to organize the situation together with photos and point cloud data while recording on-site positions you want to verify with high accuracy. Because it can be linked to planned installation locations, obstacle positions, elevation differences, and as-built verification, it is effective in reducing discrepancies between design-stage assumptions and actual site conditions.

In other words, by establishing a workflow that evaluates power generation with simulation software and verifies the site’s position and shape with LRTK, you can補完 elements that are easily overlooked in desk-based studies through practical work. Connecting planning, analysis, and on-site verification without separating them is the quickest way to reduce rework and improve the quality of decisions.

Summary

To avoid getting confused when using power generation simulation software, you don't need to memorize every feature. Clarify your objectives and assumptions, align the baseline conditions, then set up meteorological data, orientation, tilt, configuration, losses, shading, and temperature in that order, and carry the results through consistency checks, interpretation, comparison, and reporting. Just following this flow will make the meaning of the operations much clearer.

What matters most for practitioners is not producing numbers but being able to explain why those numbers came about. The twelve basic operations introduced here are the minimal and essential foundation for that. Rather than aiming for perfection at first, use them while being conscious of which input affects which result, and both accuracy and judgment will steadily improve.

And to make the analysis results more useful in practice, coordination with on-site verification is indispensable. If you want to link the designs on the screen with the conditions at the site, leveraging LRTK can help make verification work that includes location information proceed more smoothly. It is important to combine power generation simulations with a high-precision understanding of the site and to translate that into practical design work that does not end with desk-based study.