What is PVSyst? Screens and Terms Beginner Designers Should Learn

PVSyst is a specialized simulation software used to predict the energy production of photovoltaic (PV) systems and to organize design conditions and loss factors. For design beginners, it can be hard to know what to set on the initial screen, what the various terms mean, and where to look on the results screen. However, what’s important for understanding PVSyst is not learning all of its functions at once. First, it is essential to follow the workflow of energy production forecasting and grasp the meanings of the input screens, design conditions, losses, reports, and performance indicators.

In this article, for practitioners searching "What is PVSyst", we organize the screens and terms that design beginners should learn first. If you can not only calculate energy production but also understand the conditions from which those figures are derived, PVSyst becomes easier to use not simply as operational software but as a practical tool that supports design decision-making.

Table of Contents

• PVSyst is simulation software that links design conditions and energy production

• Basic screens that design beginners should look at first

• Terms to learn in Project Settings

• What to understand on the meteorological data and site location screens

• Terms to learn for azimuth and tilt settings

• Capacities and equipment conditions to understand on the system configuration screen

• Key concepts to grasp in shading and nearby obstruction settings

• Basic terms to learn on the losses settings screen

• Important indicators to check on the results screen and in reports

• Misconceptions beginners should avoid when learning PVSyst

• Improving design accuracy by combining PVSyst with on-site information

PVSyst is a simulation software that connects design conditions and power generation

PVSyst is software for predicting the energy yield of photovoltaic (PV) installations and for checking differences among design conditions and loss factors. In designing PV systems, the energy output is not determined solely by the system’s capacity. Many factors affect generation, including the site’s solar irradiance, ambient temperature, module orientation, tilt angle, shading, topography, wiring, inverter capacity, soiling, and temperature rise. PVSyst is used to input these conditions and to check annual and monthly energy production, the breakdown of losses, the performance ratio, and other metrics.

What design beginners should understand first is that PVSyst is not software that automatically guarantees power generation; it is software that predicts power generation based on the input conditions. If the input conditions match the actual site conditions, the results will be easier to use for design decisions. On the other hand, if azimuth, tilt, shading, meteorological conditions, or loss conditions are inaccurate, the output power generation may deviate from reality. In other words, when using PVSyst it is important not only to know how to operate the interface, but also to understand the meanings of the terms and conditions you enter.

The overall picture of PVSyst becomes easier to understand if you think of it as the flow that determines energy production. First, you decide the installation site and meteorological conditions, then set the panel orientation and tilt angle, and input the system capacity and equipment configuration. On top of that, you reflect loss conditions such as shading, wiring, temperature, and soiling, and finally check the resulting energy production. On the results screen you can read not only the annual energy production but also at which stages the energy is being lost. Understanding this flow makes the purpose of each screen easier to see.

When beginners learn PVSyst, it is more effective to learn the screens most directly related to energy-yield prediction in sequence rather than trying to memorize every technical item. Understanding in the order of site location, meteorological data, orientation, tilt, system capacity, shading, losses, and result reports helps connect the操作 and the thinking. PVSyst is multi-functional, but by narrowing down the screens and terms you should learn first, you can acquire the practical basics needed for work in a short time.

Basic Screens Beginner Designers Should See First

When using PVSyst for the first time, there are many types of screens, and it’s easy to get confused about where to start. The basic screens that a design beginner should look at first are the screen that manages the entire project, the screen for setting the installation site and meteorological conditions, the screen for setting orientation and tilt, the screen for configuring the system components, the screen for setting shading and losses, and the screen for checking calculation results. These screens are easier to understand if you think of them as arranged along the flow of the power generation forecast.

On the screen that manages the entire project, you organize the basic information of the power generation facilities under consideration. Here you manage which location, what type of equipment, and under what conditions will be simulated. Beginners tend to see this screen as mere file management, but in practice it is extremely important. When comparing multiple design proposals, unless you make it clear which case corresponds to which conditions, you will not be able to interpret the results later.

On the Location and Weather Conditions screen, you specify the solar irradiance and temperature that form the basis for power generation estimates. Because solar power generation is heavily influenced by local solar irradiance conditions, this screen serves as the foundation for power generation forecasts. On the Azimuth and Tilt screen, you set which direction the panel surfaces face and at what angle they receive sunlight. On the Equipment Configuration screen, you organize the panel capacity, conversion equipment capacity, and connection conditions. These screens are directly involved in the calculation of power generation.

In the Shadows and Losses screen, you set conditions to bring the ideal energy production closer to the actual expected production. By taking into account surrounding obstructions and shading between panel rows, temperature-related output reductions, wiring losses, soiling, and so on, the simulation becomes closer to real site conditions. On the Results screen, you can check annual energy production, monthly energy production, loss diagrams, performance ratio, and other metrics. For beginners, it is important not to judge based solely on the Results screen; instead, move back and forth between the Input and Results screens to verify the reasons behind the numbers.

When learning the main screens, rather than memorizing screen names, you will gain a deeper understanding by thinking about which stage of the generation forecast each screen is responsible for. If you organize it like this—installation location as the entry point for solar irradiance, orientation and tilt as the conditions of irradiance reaching the panel surface, system configuration as the conditions for generation and conversion, loss settings as the real-world reduction factors, and the result screens as the final evaluation—you will find it easier to grasp the overall picture of PVSyst.

Terms to Remember in Project Settings

In PVSyst's project settings, you organize the basic conditions for the entire project. The terms to learn here are project, variant, simulation conditions, baseline case, and comparison case. What is important for design beginners is the concept that you can manage multiple design conditions within a single project. In photovoltaic system design, it is common to compare multiple options such as changing the azimuth, changing the tilt, changing the capacity, or changing the shading conditions.

A project is the overall grouping of the power generation facility under consideration. It includes information to identify the whole, such as the installation location and the project name. A variant is like a design case within the same project where conditions are changed. For example, you can manage separately a case with a different tilt angle at the same candidate site, a case with a different system capacity, or cases that do and do not account for shading. Beginners will find it easier to compare and evaluate options if they understand the concept of variants early.

Simulation conditions are the assumptions entered to calculate power generation. They include the installation location, meteorological data, orientation, tilt, system capacity, equipment configuration, shading, losses, and so on. PVSyst’s results are calculated based on these simulation conditions. Therefore, rather than saving only the results, it is necessary to keep track of which conditions were used to perform the calculations.

A baseline case is the standard design condition that serves as the starting point for comparisons. First, create the baseline case using conditions that are considered realistic, and then create comparison cases that vary orientation, tilt, capacity, shading conditions, and so on; this makes differences in the results easier to understand. When creating comparison cases, it is important to be clear about what was changed. If multiple conditions are changed simultaneously, it becomes difficult to determine which factor is responsible for differences in energy output.

A common pitfall in project setup is postponing the organization of case names and conditions. As design studies progress, similar cases multiply. If you can’t tell which case is the latest, which case has shading, or which case reflects a capacity change, it will affect the reliability of the report. If you use PVSyst in practice, it’s important to organize things from the project setup stage so you can explain the differences in conditions.

Things to understand on the Weather Data and Installation Location screen

The meteorological data and site screens are a crucial part of PVSyst for determining the assumptions behind energy production. In solar power generation, how much solar irradiation a site receives and how temperatures vary have a large impact on the amount of energy produced. Beginner designers should first understand the terms solar irradiation, temperature, site location, latitude and longitude, elevation, and meteorological year.

Solar irradiance refers to the amount of energy from the sun that reaches the ground or the surface of panels. Because solar power generation converts solar irradiance into electricity, solar irradiance forms the basis for power output. Regions with higher solar irradiance tend to produce more electricity, while regions with lower irradiance will see less generation even with the same installed capacity. However, power output is not determined by irradiance alone. Temperature, shading, and equipment conditions also have an impact.

Ambient temperature is related to the temperature rise of the panels. In solar power generation, when panel temperature increases, output tends to decrease. Even in locations with high solar irradiation, if ambient temperature is high and conditions make panel temperature rise easily, temperature losses can be large. PVSyst uses meteorological data to handle solar irradiation and ambient temperature and calculates energy production and temperature losses.

The installation site is important when selecting meteorological data. If the candidate site and the meteorological data point are far apart, the actual conditions may differ. In mountainous areas, along the coast, in urban areas, or in regions with snowfall, trends in solar radiation and temperature can differ even between nearby locations. Beginners should, when choosing meteorological data, not simply select data that is available but be mindful to check whether it closely matches the actual conditions at the installation site.

Latitude, longitude, and elevation also play a role when considering the sun’s movement and weather conditions. Changes in latitude alter the sun’s altitude and the seasonal solar radiation conditions. Elevation and surrounding terrain can also affect temperature and solar radiation. When setting the installation location in PVSyst, it is important to verify that the location information has been entered correctly.

A common misconception beginners should avoid on the meteorological data and installation location screen is to think that selecting the meteorological data completely determines the assumptions for energy production. Actual energy generation varies with year-to-year weather differences. PVSyst's meteorological conditions are representative assumptions for predicting energy production. They do not guarantee results and should be treated as a basis for design review.

Terms to Remember When Setting Orientation and Tilt

Azimuth and tilt are terms that every beginner should learn on PVSyst's design screen. Azimuth is the parameter that indicates which direction the panels face. Tilt is the parameter that indicates the angle at which the panels are installed relative to the horizontal plane. These two are important factors that determine how much solar radiation reaches the panel surface.

In solar power generation, even at the same installation site, simply changing the panels’ orientation and tilt alters the annual energy production and seasonal output. Changing the azimuth shifts the times of day that receive more solar irradiance. Changing the tilt alters the amount of solar irradiance that can be received relative to the sun’s seasonal altitude. In PVSyst, you can set these conditions and check their impact on energy production.

Beginner designers should not just memorize orientation as the cardinal directions (east, west, south, north) but understand it as a factor that affects time-of-day and seasonal variations in power generation. For example, the way you evaluate orientation can differ if you prioritize annual energy production versus generation trends in the morning or evening. On site, roof orientation, land shape, surrounding shading, and installation conditions can make it impossible to choose an ideal orientation.

Tilt affects not only energy yield but also constructability and maintainability. Increasing the tilt angle can, depending on the season, increase solar exposure, but you must consider wind effects, racking conditions, inter-row shading, and constructability. Lowering the tilt angle can make better use of the available installation area, but attention is required for soiling, drainage, and the way shadows form. When comparing tilt angles in PVSyst, evaluate them based on site conditions as well as energy yield.

Terms to learn on this screen include azimuth angle, tilt angle, panel surface irradiance, fixed installation, and the concept of tracking. The azimuth angle indicates the direction angle, and the tilt angle indicates the angle of inclination. Panel surface irradiance refers to the amount of solar radiation that actually reaches the panel surface. Because the solar radiation that reaches a horizontal plane differs from that reaching an inclined panel surface, azimuth and tilt settings are important.

A common stumbling block when setting azimuth and tilt is focusing only on the angle that seems to maximize energy production. In practice, you need to consider the balance between energy yield, available installation area, shading, constructability, maintenance access routes, and equipment capacity. PVSyst is a tool for checking energy production when conditions change. The final decision should be made in combination with on-site constraints.

Capacities and equipment conditions you want to understand on the system configuration screen

On the system configuration screen, you configure the capacity of the solar power system and the combinations of equipment. For design beginners, this screen can feel full of technical terms, but it is an important area directly tied to power generation and losses. The terms you should learn here are: system capacity, DC capacity, AC capacity, conversion equipment capacity, capacity ratio, circuit configuration, and output limitation.

Installed capacity is a basic figure that describes the scale of a power generation facility. In general, capacity is considered separately for the panel side and the conversion-equipment side. DC capacity is the concept of the capacity that can be generated on the panel side. AC capacity is the concept of the capacity on the side from which power is drawn after conversion. In solar power generation, the balance between DC-side and AC-side capacities influences the amount of power produced and output limitations.

The conversion equipment capacity is the capacity of the equipment that converts the power generated by the panels into a usable form. If the conversion equipment capacity is smaller than the panel capacity, output may be curtailed during hours of strong solar irradiance. This is called output limitation. Conversely, increasing the panel capacity to some extent can make it easier to secure generation during hours of weak solar irradiance. In PVSyst, you can check the energy generation and losses resulting from this capacity balance.

The capacity ratio is a term used to consider the relationship between the DC-side capacity and the AC-side capacity. Beginners should not memorize the capacity ratio as a mere number, but understand it as an indicator for assessing the balance between power generation and output limitations. Changing the capacity ratio can affect annual power generation, losses due to output limits, and how equipment is utilized.

Circuit configuration is also important. How the panels are connected changes the voltage and current conditions. If the circuit configuration is not appropriate, the equipment may fall outside its operating range or the power generation efficiency may decrease. On PVSyst's system configuration screen, you are required to verify whether the combinations of equipment are valid from a design viewpoint.

What beginners should avoid on this screen is assuming that simply increasing capacity is better. Increasing capacity may increase energy production, but it's important to balance that with site conditions, shading, wiring, the capacity of conversion equipment, and maintainability. In PVSyst, you should evaluate not only the energy production resulting from capacity changes but also the losses and the performance ratio.

Key considerations when configuring shadows and nearby obstacles

Settings for shading and nearby obstacles are extremely important when using PVSyst in professional practice. In photovoltaic power generation, shadows from surrounding buildings, trees, slopes, equipment structures, and between panel rows affect energy production. If the impact of shading is not evaluated correctly, simulations may indicate high energy yields while actual operations may fall below expectations.

The terms you should learn on this screen are near-field shading, far-field shading, obstructions, terrain shading, inter-row shading, and shadow loss. Near-field shading refers to shadows caused by buildings, trees, equipment structures, and similar objects located close to the panels. Far-field shading refers to shadows where the sun is obscured by elements located at a distance, such as mountains or high terrain. Terrain shading is the shadowing that occurs due to elevation differences or slopes around the site. Inter-row shading is the phenomenon in which panels or mounting structures in a front row cast shadows on rear rows.

What’s important in shading assessment is not just whether shading exists, but when, where, and to what extent it occurs. A location that appears to have little shading during summer daytime can have long shadows on winter mornings and evenings when the sun’s altitude is low. A single site visit is not enough to determine the impact of shading over the course of a year. In PVSyst, by entering shading conditions you can check the effects on annual and monthly energy production.

Shadow loss refers to the amount by which power generation is reduced due to shading. If shadow loss is large, consider changing the layout, reassessing the installation area, adjusting row spacing, or avoiding areas close to obstructions. However, the goal is not solely to reduce shadow loss to zero. Depending on site conditions, it may be impossible to avoid some shading. What is important is to identify the causes of the shading and separate what can be improved from what must be accepted.

What beginners often struggle with in shading settings is the accuracy of site information. If the positions and heights of obstacles, the installation area, orientation, or terrain elevation differences are inaccurate, PVSyst’s shading assessment will also be inaccurate. Before operating the shading screen, it is important to clarify what should be checked on site. Because photos alone can make distances and heights hard to determine, you need to prepare the input conditions based on location data and survey information.

Basic Terms You Should Know on the Loss Settings Screen

On the Loss Settings screen, you configure the conditions used to correct the ideal energy generation to values closer to actual production. In solar power generation, the energy received from the sun does not directly become electrical energy. Various losses occur, such as reflection, soiling, temperature rise, wiring, equipment conversion, output limitation, and mismatch. PVSyst evaluates the energy production taking these losses into account.

For beginners in design, the terms they should remember include temperature loss, wiring loss, soiling loss, mismatch loss, conversion loss, and output-limiting loss. Temperature loss refers to the decrease in output caused by a rise in panel temperature. Even in seasons with high irradiance, if the ambient temperature is high and the panel temperature rises, power generation efficiency may decrease. Wiring loss is the loss that occurs during the process of transmitting generated power. The impact varies depending on the wiring distance and configuration.

Soiling loss occurs when dust, sand, pollen, bird droppings, residual snow, and other deposits adhere to the panel surface, reducing its ability to receive solar radiation. The impact of soiling varies depending on site conditions and cleaning schedules. Mismatch loss refers to the overall output not matching the ideal due to differences in characteristics or operating conditions among panels. Conversion loss is the loss that occurs during processes such as converting direct current to alternating current. Output limitation loss occurs when, due to equipment configuration or capacity conditions, the power that could be generated is capped at an upper limit.

What matters in loss settings is not making the losses look small, but setting reasonable values that match the site conditions. If you reduce losses, the estimated power generation will look higher, but if it does not match the actual site, the reliability of the forecast will decrease. Conversely, if you set large losses without justification, you may end up underestimating the actual power generation.

PVSyst's loss settings also affect the explanatory power of the generation forecast. When stakeholders ask for the basis of the predicted generation, it is important to be able to explain which losses were assumed and how. The loss settings screen is not merely a detailed configuration page but an important screen that supports the realism of the generation estimate. Beginners should consciously learn the meaning of each loss one by one and read them in conjunction with the loss chart on the results screen.

Key metrics to check on the results screen and in reports

In PVSyst's result screens and reports, you can check the energy production, losses, and performance indicators calculated based on the input conditions. For design beginners, the important indicators to look at first are annual energy production, monthly energy production, performance ratio, loss diagram, shading losses, temperature losses, output limitations, and generation per unit capacity. By viewing these together, you can understand the overall picture of energy production and the reasons behind it.

Annual energy production is a figure that indicates how much electrical energy a power generation facility is expected to produce over the course of one year. It is the metric most likely to attract attention in business plans and equipment comparisons, but you cannot judge the quality of a design by this number alone. A high annual energy production may simply reflect a large installed capacity, or it may result from overly optimistic loss assumptions. It is important to check annual energy production as an initial indicator and then examine other metrics.

Monthly power generation is an indicator used to assess seasonal generation trends. In solar power generation, solar irradiance, ambient temperature, and the effects of shading vary by season. If generation falls sharply in winter, you should check not only the insolation conditions but also the impact of shading. If summer generation does not increase as much as expected, it is worth checking for temperature-related losses and output limitations.

The performance ratio is an indicator used to assess how effectively an installation converts the solar irradiance it receives into electricity. While energy output is affected by system capacity and irradiation conditions, examining the performance ratio makes it easier to understand the overall efficiency of the installation. If the performance ratio is low, check for losses such as shading, temperature, wiring, equipment configuration, and soiling. Even when the performance ratio is high, it is necessary to verify that the input conditions are realistic.

A loss diagram shows how much of the energy received from the sun is lost at each stage before reaching the final power output. It may seem information-heavy to beginners, but following the flow of energy from top to bottom makes it easier to understand. Viewing it in the sequence of the solar irradiation stage, losses at the panel surface, temperature-related losses, electrical losses, and conversion losses helps organize the reasons for reduced power generation.

When reading a report, check not only the figures but also the input conditions. You cannot assess the validity of the results unless you confirm that the site location, meteorological data, azimuth, tilt, system capacity, shading, and loss assumptions are as intended. It is important to read a PVSyst report not as a mere list of results but as material to explain the relationship between design conditions and energy production.

Misconceptions Beginners Should Avoid When Learning PVSyst

A common misunderstanding beginners learning PVSyst should avoid is believing that simply entering inputs will automatically produce the correct energy output. PVSyst is an advanced simulation software, but its results depend on the input conditions. If the installation site, meteorological data, azimuth, tilt, shading, or loss assumptions are inaccurate, the predicted energy production will also deviate from reality. Learning how to operate the software and being able to set correct assumptions are separate skills.

Another misconception is believing that looking at annual energy production alone is sufficient. Annual energy production is important, but unless you also look at monthly energy production, loss diagrams, and the performance ratio, you won't understand the reasons behind the observed production. Even if the annual production is high, there may be significant shading or output limitations. Conversely, even if the annual production is somewhat low, the design may nonetheless be reasonable and stable for the site conditions.

Be wary of the misconception that simply minimizing losses is always better. There are losses that cannot be avoided because of local site conditions. If an area with shading shows no shading losses at all, there may be an omission in the settings. If the wiring distance is long but the wiring losses are unrealistically small, you should check the input conditions. The purpose of PVSyst is not to make the energy yield look high, but to be able to explain a power generation amount that is close to reality.

There is also a misconception that memorizing the terminology alone will make the software usable. PVSyst uses many technical terms, but what matters is understanding the meaning of those terms in relation to the flow of energy production. Orientation and tilt relate to the irradiance on the panel surface, shading reduces the solar irradiance that can be received, temperature losses affect conversion efficiency, and wiring losses occur in the process of transmitting power. By understanding which stage each term relates to, the meaning of the screens becomes much clearer.

When learning PVSyst, it is important not to try to create a perfect simulation all at once. First create a baseline case, then change orientation, tilt, shading, capacity, and loss conditions little by little while checking the results. By experiencing how the results change when you alter input conditions, your understanding of PVSyst will deepen. What beginners need is not to master complex functions all at once, but to understand the basic screens and key terms in line with the flow of power generation.

Combining PVSyst with On-Site Data to Improve Design Accuracy

PVSyst is simulation software for evaluating the energy yield, losses, and performance indicators of photovoltaic power systems and for verifying the validity of design conditions. The screens that design beginners should learn first are Project Settings, Weather Data, Orientation and Tilt, System Configuration, Shading, Losses, and the Results Report. These screens may look separate, but they are connected as a workflow that determines the energy production.

Important terms are also easier to understand if learned according to the flow of power generation. The installation location and meteorological data set the assumptions for solar irradiance and temperature. Orientation and tilt affect the amount of solar irradiance reaching the panel surface. System capacity and equipment configuration determine the conditions for power generation and conversion. Shading and losses are adjustment factors used to bring estimated generation closer to actual generation. On the results screen, review annual generation, monthly generation, loss diagrams, and the performance ratio to interpret the reasons behind the generation values.

To use PVSyst correctly, not only screen operation but also the accuracy of on-site information is essential. If orientation, tilt, installation area, obstacle positions, elevation differences, or wiring routes are inaccurate, the simulation results can easily diverge from reality. Conditions related to shading and terrain in particular have a large impact on energy yield and the performance ratio, so they must be accurately determined on site.

For design beginners to use PVSyst in practice, it is important to first understand the basic interface and terminology, then reflect the site conditions in the model inputs, and finally aim to be able to explain the reasons behind the results. Rather than simply producing generation numbers, if you can explain why that generation occurs, which losses are most significant, and which conditions should be reviewed to achieve improvements, PVSyst becomes a powerful tool for design decision-making.

If you want to streamline on-site position checks, grasp the installation area, record obstacles, and verify azimuth and elevation differences, leveraging an iPhone-mounted GNSS high-precision positioning device like LRTK makes it easier to organize the site conditions to input into PVSyst. With high-precision location data that clarifies the installation area and the causes of shading, the basis for simulation results becomes clear, and even novice designers can more effectively explain power generation forecasts. By combining PVSyst screen and terminology understanding with accurate positioning information obtained on site, you can further raise the accuracy and practical reliability of solar power generation design.