7 ways to read a PVSyst report to explain it to your boss

When explaining a PVSyst report to your manager, the most important thing is not to read technical terms in order. What your manager wants to know is, more than the detailed formulas themselves, how much generation this power plant can be expected to produce as a business, whether it will be lower or higher than assumed, where the risks lie, whether there are problems with the design or the underlying assumptions, and what should be decided next.

PVSyst is a software widely used for simulating the power generation of photovoltaic power plants, but its reports list a very large number of items such as irradiance, energy production, PR, Specific Yield, losses, temperature, shading, wiring, PCS, grid connection, and output curtailment. As a result, for someone seeing it for the first time it can be difficult to know where to look, and those explaining it tend to start from the details.

However, when explaining to a supervisor, it is effective to start with the conclusion, then present the supporting evidence, and finally summarize any concerns and the next actions. The purpose of reading a PVSyst report is not merely to check the numbers, but to convert them into a form that can be used as decision-making material for a power generation business.

This article explains seven practical ways to read a PVSyst report when presenting it to your supervisor. To make them useful for internal reporting, design reviews, feasibility assessments, preparation of materials for financial institutions, and preliminary organization before explaining to customers, they are organized with attention to the sequence of explanations used in real-world practice.

• Basics for explaining a PVSyst report to your manager

• Reading 1: Start with the conclusion on energy production

• Reading 2: Use Specific Yield to normalize differences in scale

• Reading 3: Explain the plant’s performance using PR

• Reading 4: Confirm with solar irradiance and weather conditions as the baseline

• Reading 5: Use the Loss Diagram to organize the reasons for reduced energy output

• Reading 6: Verify the validity of design conditions and input values

• Reading 7: Summarize the risks to communicate to your manager and the next items to check

• Ways of speaking to avoid when explaining a PVSyst report

• Practical summary format for manager briefings

• Perspectives to connect PVSyst results to on-site verification

• Summary

Basics for Explaining a PVSyst Report to Your Manager

When explaining a PVSyst report to your manager, you do not need to go through the report page by page. In fact, attempting a detailed, page‑by‑page explanation can make the key conclusions harder to see. What your manager wants to know first is: how much the annual energy production is, how it compares to the expected level, which factors have a significant impact on profitability, and whether there are any inconsistencies or anomalies in the design or input assumptions.

Therefore, the entry point of an explanation should always be the conclusion. For example, "Under these conditions the annual power generation is approximately X MWh, and on a per‑1 kW installed capacity basis it is Y kWh/kWp. The PR is Z%, which is not significantly different from typical levels. However, shading losses and temperature losses are somewhat large, and these are the main causes of the reduction in power generation," — in this way, it is important to present the overall picture within the first few tens of seconds.

In explaining PVSyst reports, the ability to translate numerical values into business decisions is required more than knowledge of fine terminology. Annual energy production is directly linked to revenue from power sales and the benefits of self-consumption. PR indicates the overall efficiency of the system. Specific Yield is an indicator that looks at energy production per unit of installed capacity. The Loss Diagram is a reference for seeing which factors caused reductions and by how much, from solar irradiation to the final energy production.

When explaining to your supervisor, it's important not to present all of these with the same weight, but to reorder them in the sequence needed for decision-making. The recommended flow is: first power generation, next kWh/kWp, then PR, followed by solar irradiance conditions, loss factors, design conditions, and finally risks and countermeasures. This order allows you to move naturally from conclusions to their basis, making it easier for the listener to understand.

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A PVSyst report is not something that should be judged by the results alone. Because you will always get numbers if you enter conditions, whether those numbers are correct depends greatly on the validity of the input conditions. Therefore, when explaining to your boss, saying only “PVSyst produced these results” is weak; you need to add the assumptions: “This generation figure is the result assuming solar irradiance, system capacity, loss settings, PCS conditions, and shading conditions.”

When explaining to a supervisor, what’s particularly important is to be able to state in one sentence whether the result is good or bad. For example, even if power generation is low, the implication differs depending on whether it’s low because the solar irradiance assumptions are conservative, because there is significant shading, because PCS limits are restrictive, or because temperature losses are large. Rather than simply saying "it's low," you should organize the explanation as "the low value is mainly due to these two items."

Reading Tip 1: State the Conclusion about Power Generation First

When presenting a PVSyst report to your supervisor, the first item to check is the annual energy production. The report contains multiple energy-related figures depending on conditions, such as Produced Energy, Energy injected into grid, E_Grid, EArray, EOutInv. When explaining to your supervisor, you need to make clear which figure you will treat as the final production value.

Generally, for grid-connected photovoltaic power plants, the most important metric is the amount of electricity ultimately delivered to the grid. In PVSyst, the values corresponding to Energy injected into grid and E_Grid are often used to explain the project's electricity sold or the amount transmitted. On the other hand, array output and the generation on the PCS input side are useful for verifying internal equipment performance, but they are somewhat preliminary figures and not the ones you should present first as a conclusion to your supervisor.

In the explanation, first state, "The annual amount of electricity ultimately injected into the grid is X MWh." Then add, "By month, which months tend to be higher and which months tend to be lower." For solar power generation, it does not necessarily peak in summer. Depending on the region, the tilt angle, temperature, snowfall, the rainy season, and solar irradiance conditions, spring or autumn can sometimes generate more efficiently. Because your supervisor may ask, "Why isn't summer the highest?", it's reassuring to be able to briefly explain the relationship between solar irradiance and temperature-related losses.

When explaining annual generation, it is important to provide not only the absolute value but also a point of comparison. For example, comparing it with the previous simulation, other companies' reports, rough estimates, past projects, neighboring sites, or internal standards makes the numbers easier to interpret. Saying that annual generation is 10,000MWh alone doesn't tell you whether that's good or bad. However, explaining it as "1.8% lower than the previous proposal," "2.5% higher than other companies' reports," or "within the expected range per unit of installed capacity" enables judgment.

When explaining power generation, how numbers are rounded is also important. For reports to your boss, you don't need to read out overly detailed digits. For example, rather than reading the number 10,234.567 MWh as is, it's easier to convey it as "about 10,235 MWh per year" or "about 10.2 GWh". However, if the figures are to be used in comparison tables or contract terms, you should retain the original number in a separate document.

Also, the power generation estimated by PVSyst is only a simulation result. It is not measured data. Therefore, when explaining it, it is important to add the note: "This power generation is an expected value based on the specified meteorological data and design conditions." Actual power generation varies due to year-to-year weather, equipment outages, soiling, snow accumulation, curtailment, failures, maintenance, grid constraints, and other factors.

When explaining to your supervisor, don’t present the power generation figures in isolation; convey them together with whether that generation is sufficient relative to the revenue plan, whether the assumptions are conservative or optimistic, and where the potential causes of decline lie. Even if the generation appears high, the input assumptions may be too lenient. Conversely, if the generation appears low, it may be realistic because conservative assumptions were made for snow, shading, and output curtailment.

At this stage, the explanation for a supervisor is easier to understand if summarized as follows: "The final generation in this report is approximately X MWh per year. We will later check generation relative to installed capacity in kWh/kWp, but in absolute terms it does not deviate significantly from the assumptions of the business plan. However, on a monthly basis reductions are observed in winter or summer, and the main causes are one of the following: solar irradiance conditions, temperature, shading, snow accumulation, or loss settings."

Interpretation 2: Normalize scale differences using Specific Yield

After checking the annual energy generation, look at the Specific Yield. Specific Yield is an indicator that shows the annual energy generation per 1 kWp of installed capacity. The unit is often expressed as kWh/kWp, and it makes it easy to compare power plants of different sizes.

When explaining to your boss, it can be clearer to paraphrase Specific Yield as "size-normalized generation." For example, a 10 MW plant and a 50 MW plant will, of course, have very different absolute annual generation. However, when viewed in kWh/kWp, it's easier to compare which plant is expected to generate more efficiently.

In PVSyst reports, Specific Yield may appear as a concept similar to Final yield or Yf. Yf can be understood as the final energy production divided by the installed capacity. When explaining to a supervisor, it is more practical to describe it as "an indicator of how much power is generated relative to the installed capacity" rather than getting too caught up in strict differences in terminology.

When assessing Specific Yield, always take regional characteristics into account. Even with the same design, solar irradiance, temperature, and snowfall conditions differ between Hokkaido, Tohoku, Kanto, and Kyushu. Therefore, it is risky to evaluate performance simply based on a national average. In Hokkaido, lower temperatures can be advantageous for module efficiency, but the area may be affected by snow and winter solar radiation. In Kyushu, while solar irradiance is abundant, higher temperatures can lead to greater thermal losses.

In addition, tilt angle and orientation also have a major impact on Specific Yield. A south-facing system with an appropriate tilt will produce a different annual energy output than one whose orientation is offset due to topographical constraints, even with the same installed capacity. In large ground-mounted projects, racking spacing, shading, site shaping, and slope orientation also have an effect. For rooftop installations, roof orientation, roof pitch, and shadows from surrounding buildings are important.

When explaining to your supervisor, it is not sufficient to simply state, "This Specific Yield is high" or "low." You need to explain why it is at that level by relating it to region, slope, orientation, shading, and loss conditions. For example, saying, "The Specific Yield for this project is slightly low, but this reflects a conservative assessment of terrain shading and winter conditions," communicates a result based on assumptions rather than a mere low rating.

Specific Yield is also very useful for comparing reports from other companies. When comparing results from other companies’ PVSyst or other software, the absolute value of annual energy production is influenced by differences in system capacity. Even if the system capacities differ slightly, converting to kWh/kWp allows a fairer comparison. However, you must always confirm whether the basis is DC capacity or AC capacity. If the basis differs, Specific Yield will look different even for the same energy production.

When explaining to your manager, use Specific Yield to express in one phrase how much this power plant generates relative to its size. Then compare it with past projects and internal standards. For example, you can explain: "We expect approximately how many kWh per year per 1 kWp of installed capacity. There is no significant deviation compared to past similar projects. However, because shading losses are large, there is room for improvement by reviewing the shading conditions."

Specific Yield is a very powerful intermediate metric for checking the plausibility of energy production. For managers, an explanation framed as "how much is generated per 1 kW" can be more intuitively understandable than a large number like "X MWh". When explaining a PVSyst report, always make sure to present annual energy production together with Specific Yield.

How to Read 3: Explain the Power Plant's Perceived Performance Using PR

When explaining a PVSyst report to your manager, PR is a very important metric. PR stands for Performance Ratio and is a metric that indicates how efficiently a solar power plant converts the incoming solar energy it receives into final electrical output. For managers, it is easier to understand if you explain it as "a metric that indicates the overall efficiency of the entire plant."

PR is used to understand the magnitude of system losses, independently of whether the solar irradiance is high or low. In regions with high irradiance, the power generation will be larger, but that alone does not mean the plant’s performance is good. Conversely, in regions with low irradiance, PR can be high if losses are small. In other words, PR is an indicator for assessing the system’s efficiency — including design and losses — rather than the site’s solar irradiation potential.

When explaining PR to your boss, first present the figures, then explain what they mean. For example, you can say, "The PR for this project is X%. This indicates the overall efficiency after solar irradiation, once temperature losses, shading losses, wiring losses, PCS losses, and other losses have been subtracted."

PR may look better the higher it is, but a simply high value does not necessarily mean it is reliable. If loss settings are too lenient, PR will be overestimated. For example, if soiling loss is set too low, if snow is not accounted for, if shading is not sufficiently considered, if temperature conditions are assumed to be more favorable than reality, or if wiring losses are underestimated, PR can appear higher than it actually is.

Conversely, even if PR is low, it does not necessarily mean the design is poor. PR can be low in cases such as when winter losses are conservatively estimated in snowy regions, when terrain shading is significant, when PCS capacity is limited causing peak clipping, when output curtailment or grid constraints are anticipated, or when there are constraints on tilt and azimuth. In such cases, it is important to explain whether the low value is reasonable.

When explaining to a supervisor, we do not evaluate PR on its own but review it together with the Loss Diagram. The reason PR is low will appear in the Loss Diagram. We check whether temperature loss, shading loss, IAM loss, wiring loss, or PCS loss is large, or whether mismatch, degradation, or soiling are having an effect.

When comparing PR with other companies' reports, you need to pay attention to differences in assumptions. Even for the same power plant, PR will change if the meteorological data used, albedo, soiling losses, wiring losses, PCS efficiency, temperature loss coefficient, how shading is treated, or the presence of power curtailment differ. Therefore, when explaining to your manager, you should explain not only "how many percent the PR differs" but also "which loss settings are the primary cause of the difference."

PR is a metric commonly seen in explanations for financial institutions and investors. However, it is risky to judge business viability based solely on PR. What directly ties to revenue from electricity sales and the benefits of self-consumption is the final generation output, and PR is a supplementary indicator that assesses whether that output is being produced at a reasonable efficiency. Therefore, if you explain to your boss, "The generation output is the conclusion; PR is the indicator to check the quality of that output," the positioning becomes clear.

A practical way to explain PR is: "This PR is an efficiency metric that reflects the total losses of the system. The current value is not at an extremely high or low level. However, since shading losses and temperature losses are pulling the overall figure down, if you are looking for areas to improve, these two items would be the candidates."

How to Read 4: Confirm Based on Solar Radiation and Meteorological Conditions

The energy output in a PVSyst report depends heavily on the meteorological data. No matter how good the design is, if the input solar irradiance is low, the predicted energy will be low. Conversely, using data with higher irradiance will produce higher estimated energy. Therefore, when explaining this to your supervisor, you need to confirm which meteorological dataset is being used as the basis for the energy estimates, whether the irradiance is reasonable, and whether the temperatures are realistic.

In PVSyst, several solar radiation–related items appear, such as Global horizontal irradiation, Diffuse irradiation, and Global incident in collector plane. For a supervisor, it is not necessary to explain every detailed item. What is important is to understand and explain the difference between "irradiation on the horizontal plane" and "irradiation incident on the panel plane."

Horizontal solar irradiance is the basic amount of solar radiation that falls on a region.

On the other hand, panel surface irradiance is a value closer to the actual solar radiation incident on the panel surface, taking into account module tilt and azimuth, topography, reflections, and diffuse/scattered light. What directly affects solar power generation is, ultimately, the irradiance that reaches the panel surface.

When explaining to your supervisor, always state which meteorological data were used to produce the estimated power generation. Results vary depending on the source of the meteorological data—Meteonorm, SolarGIS, nearby observation data, on-site measured data, etc. If you are comparing multiple datasets, it is easier to explain if you organize which datasets are conservative and which tend to yield higher estimates.

Ambient temperature is also important. Solar modules see a drop in power output when the air temperature or module temperature rises. Therefore, even in summer when solar irradiance is high, temperature-related losses can be large and generation may not increase as much as expected. From a manager’s point of view, they might think “if there is more sunlight, power generation should be at its maximum,” but in reality temperature losses can make spring or autumn more efficient for power generation.

In snowy regions, winter solar irradiance, albedo, snow-induced shading, and whether snow removal is performed all affect the results. Setting a high albedo can be expected to increase power generation due to reflection from the snow surface, but in practice there will be periods when panels cannot generate electricity because snow accumulates on them. Therefore, in snowy regions it is necessary to balance the gains from albedo with the losses caused by snow accumulation.

When explaining solar irradiance, don't just state whether the power output is high or low; indicate whether the assumed solar irradiance is reasonable. For example, if you can explain that the primary reason the output appears low is not equipment performance but that the solar irradiance in the meteorological data used is conservative, you can separate judgments about design issues from those about the meteorological assumptions.

When comparing with reports from other companies, differences in solar irradiation are a very significant issue. Even with the same equipment conditions, if the annual solar irradiation in the meteorological data differs by a few percent, the power generation will also change significantly in the same direction. Therefore, when explaining the comparison results to your manager, first confirm "what portion of the generation difference is attributable to the difference in solar irradiation."

A convenient way to describe the meteorological conditions is as follows: "The reported power generation is based on the solar irradiation conditions in the meteorological data used. When comparing with other companies' reports, differences in solar irradiation are the primary factor affecting differences in generation. Beyond that, it is necessary to review differences in loss settings and design conditions."

How to Read 5: Summarizing the Reasons Why Power Generation Decreases in the Loss Diagram

When explaining a PVSyst report to your manager, the Loss Diagram is extremely important. The Loss Diagram is a chart that shows where and how much loss occurs as solar irradiance enters the solar modules, becomes DC power, is converted to AC by the PCS, and is ultimately delivered to the grid. For managers, it's easier to understand if you describe it as "the breakdown of the reasons why generation is reduced."

When looking at PVSyst results, simply concluding that the energy production is high or low does not tell you what needs to be improved. By examining the Loss Diagram, you can identify the primary causes of reduced generation. For example, if shading losses are large, you should consider reviewing the layout, racking spacing, surrounding obstacles, and terrain. If temperature losses are large, check the mounting method, ventilation conditions, and module characteristics. If wiring losses are large, check cable length, conductor size, voltage, and the placement of combiner boxes and PCS.

Common losses that frequently appear in a Loss Diagram include IAM loss, shading loss, soiling loss, temperature loss, mismatch loss, DC wiring loss, PCS loss, AC wiring loss, transformer loss, and auxiliary equipment loss. When explaining to a supervisor, you do not need to describe all of them in detail. It is important to present them in order from the largest losses and to focus on the top few items that are affecting power generation.

What to pay special attention to is the addition of loss rates. In PVSyst's Loss Diagram, the reference energy changes at each stage, so simply adding the displayed loss rates can be misleading. When explaining to your supervisor, rather than delving into the detailed calculation structure, it's sufficient to say, "This diagram shows the step-by-step decrease from solar irradiation to the final power output."

Shading loss is an item that is relatively easy to convey to supervisors. Sunlight reaching the panels is reduced by shadows from surrounding mountains, buildings, and trees, by shading between mounting racks, and by terrain undulations, so power generation decreases. If shading loss is significant, consider reviewing the layout, adjusting rack spacing, changing the installation area, the feasibility of tree removal, and the impact of terrain modification.

Temperature losses are also important. Solar modules produce less output as their temperature rises. Because module temperatures increase during periods of strong solar irradiance, an increase in irradiance does not necessarily translate directly into an increase in energy production. When explaining this to your supervisor, saying, "Although summer has higher solar irradiance, temperature-related losses also increase, so in terms of power generation efficiency spring or autumn may be better," will make it easier for them to understand.

Wiring losses are important from the standpoint of design review. When DC-side wiring is long, wire diameter is small, current is large, or the PCS is located far away, losses increase. It is necessary to confirm whether the wiring losses set in PVSyst match the actual design. When explaining to your supervisor, tell them, "Because wiring losses vary depending on how thoroughly the design is finalized, they need to be rechecked based on the actual cable lengths and conductor sizes."

PCS losses and clipping are also important. If the PCS capacity is small relative to the DC capacity, output can become capped during periods of strong solar irradiance, and some of the potential generation may be curtailed. This can be described as peak cut or clipping. When explaining to your manager, saying "By keeping PCS capacity down you lower equipment costs but may lose some generation" makes it easier to understand as a trade-off between design and project economics.

When explaining to a supervisor using a Loss Diagram, it is more effective to narrow the main losses down to about three rather than covering many detailed items. For example: "The main losses this time are temperature, shading, and PCS conversion. Of these, temperature is hard to avoid as a regional condition; shading has room for improvement by revising the layout; PCS losses are within the equipment specification range." Explain by separating losses that can be controlled from those that are difficult to control.

Reading 6: Verify the validity of design conditions and input values

When explaining a PVSyst report to your manager, it is very important to check the validity of the input conditions as well as the results. PVSyst performs calculations based on the inputs entered, so if those inputs don't match reality, the reported energy production will be a weak basis for decision-making.

The first thing to check is the system capacity. Verify that the number of modules, module output, string configuration, number of PCS units, PCS capacity, and DC/AC ratio match the drawings and equipment specifications. Even a small difference in system capacity will change the absolute value of annual power generation. When comparing with another company's report, always confirm that the DC capacity is exactly the same.

Next, we review the specifications of the modules and PCS. We check whether the module’s nominal output, temperature coefficient, degradation rate, low-irradiance characteristics, PCS efficiency, MPPT range, maximum input voltage, maximum current, and power factor settings are appropriate. If the model selected from the equipment database differs from the actual product used, the simulation results will be affected. Because similar model numbers can have different characteristics, confirming the model number is fundamental.

Mounting-structure conditions are also important. Verify that the tilt angle, azimuth, racking spacing, inter-row pitch, installation height, and topographical conditions match the actual plan. In particular for ground-mounted installations, whether the array faces due south or is rotated toward the east or west, whether there is terrain slope, and what the surface will be like after site grading all affect solar irradiance and shading losses. If the tilt angle differs, not only the annual energy yield but also the monthly generation profile will change.

Don't overlook shading settings. In PVSyst you can set surrounding obstructions and inter-row (between racking) shading as Near Shadings. If shading is not included, the energy production may be overestimated. Conversely, if the shading model is overly conservative, the energy production may be underestimated. When explaining to your supervisor, you need to be clear about how far the shading conditions have been modeled.

Soiling losses and snow losses also carry significant weight as input values. Whether you enter a constant annual soiling loss, set it by month, or anticipate winter losses in snowy regions will change the energy output. When explaining to your supervisor, concisely state "what percentage of soiling loss is assumed in these results" and "how the impact of snow is treated."

We will verify whether the wiring losses have been entered as estimated values or calculated from the actual cable lengths and conductor sizes. In PVSyst you can set DC wiring losses and AC wiring losses, but in the early stages standard or provisional values may be used. As the design progresses, a review based on the actual cable routes will be necessary.

Transformer losses and auxiliary equipment losses cannot be ignored in utility-scale solar. There are items that affect the final amount of energy transmitted, such as the AC side after the PCS, step-up transformers, switchgear cubicles, monitoring devices, air conditioning, and auxiliary equipment for battery storage if present. If you do not check how much of these are included in the PVSyst report, discrepancies will arise when comparing with other documents.

When explaining input conditions to your supervisor, you don't need to read out a detailed list of settings. What matters is whether there are any unusual assumptions that would significantly affect power generation. In your explanation, say something like, "Based on our checks of installed capacity, meteorological data, shading, losses, and PCS conditions, there appear to be no major input errors. However, wiring losses are currently an estimate and will need to be updated after detailed design." In this way, convey the items that have been verified separately from those that are not yet finalized.

By including this interpretation, the explanation in the PVSyst report becomes not merely a presentation of results but a report that also includes quality verification. It also makes it easier for supervisors to understand whether these numbers can be trusted and whether there are still points that need to be checked.

How to Read 7: Summarize the Risks You Should Communicate to Your Supervisor and the Next Items to Confirm

In the final stage of explaining a PVSyst report to your manager, organize the risks and the next items to verify. What your manager ultimately wants is not memorization of detailed numbers, but the information needed for decision-making. Therefore, conclude the explanation by clarifying "how these results should be interpreted" and "what should be checked next."

First, let's organize the power generation risks. Power generation risks include uncertainty in meteorological data, year-to-year weather variability, snow accumulation, soiling, shading, equipment outages, curtailment, and equipment degradation. PVSyst is a simulation based on a standard year and set conditions, and does not guarantee the same annual energy production. Therefore, you need to tell your manager, "This is an expected value, and in reality there is year-to-year variability."

Next, we will outline the design risks. At stages where the design is not yet finalized, the racking layout, PCS placement, cable routing, equipment models, tilt angles, and site development plan may change. If these change, the PVSyst results will also change. Therefore, it is safer to state, "These results are based on the current design conditions, and re-simulation will be required after detailed design."

Third, there is a risk in making comparisons. When comparing other companies' reports or past projects, simply looking at energy production or PR alone can lead to misunderstandings. Differences in weather data, loss assumptions, capacity basis, treatment of degradation, whether curtailment is applied, shadow modeling, albedo, soiling losses, and so on will change the results. Tell your boss, "Assessing the differences requires a comparison of the underlying assumptions."

Fourth, there is business risk. Even a slight change in power generation can affect electricity sales revenue and investment payback over the long term. Especially in large-scale projects, a 1% difference in generation can result in a large monetary difference. When explaining to your boss, being able to convert generation differences into revenue impact is extremely useful as decision-making material. For example, if you can show, "If generation changes by 1%, roughly how much would annual electricity sales revenue change?" you can convey the importance of the PVSyst results.

Fifth, there are risks associated with on-site verification. Even if things appear fine in PVSyst, on-site factors such as trees, terrain, nearby structures, snow accumulation, drainage, construction constraints, and maintenance access routes can have an impact. In particular, shading, soiling, and snow strongly depend on site conditions. Therefore, do not separate PVSyst results from on-site verification; combining drone surveying, point cloud verification, site photos, 3D models, and AR verification as needed will increase the reliability of the explanation.

When giving a closing explanation to your superior, it's effective to summarize it into four points: "Conclusion", "Primary cause", "Risks", and "Next actions". For example, "The project's annual power generation is generally within the expected range. PR is not significantly off either. The main losses are temperature and shading, and shading in particular leaves room for layout verification. As next steps, we should scrutinize site conditions and wiring losses, and check discrepancies against other companies' reports."

If you organize it this way, your manager can understand the key decision points even without specialist knowledge of PVSyst. The thing to most avoid when explaining a PVSyst report is simply reading the report’s figures in order and leaving people unsure of what you are trying to say. Always finish by clearly stating what is known, what remains unconfirmed, and what decisions need to be made.

Speaking styles to avoid when explaining a PVSyst report

When explaining a PVSyst report to your boss, there are ways of speaking you should avoid. The first thing to avoid is starting with technical jargon. For example, if you suddenly list GlobHor, GlobInc, EArray, E_Grid, Yf, Yr, PR, IAM, etc., the audience will lose sight of the overall picture. Technical terms should be used when necessary, but at the outset it’s better to replace them with words like energy production, efficiency, losses, and risk.

Next, what you should avoid is presenting numeric values in isolation. Simply saying "PR is X%" or "power generation is Y MWh" does not indicate whether those figures are good or bad. You must always include a point of comparison or a judgment criterion. Explain what you are comparing them to and in what way — for example, the previous proposal, a competitor's proposal, past projects, internal assumptions, or the typical range.

Also, you should avoid presenting PVSyst results as absolute. PVSyst is a very useful simulation tool, but it depends on the input conditions. If the meteorological data or the loss settings change, the results will change as well. When explaining to your supervisor, state "these are the results under these conditions," and make it clear which conditions are uncertain and which items have high sensitivity.

When power generation is low, it is risky to immediately attribute it to poor design. The cause of the low output may lie in conservative weather data, snow accumulation settings, or stringent loss assumptions. Conversely, when power generation is high, it is also risky to immediately judge the results as good. Loss settings may be too lenient, making the outcome more optimistic than reality.

In explanations to a supervisor, avoid getting too bogged down in details. Of course, detailed checks are necessary. However, if you explain every loss item one by one in detail during the initial explanation, the important points will get buried. It's better to focus first on the top-level loss factors and go into detail only if there are questions.

Furthermore, when comparing against other companies' reports, it is not sufficient to simply say "this one is higher" or "this one is lower." In comparisons, you need to align and examine factors such as solar irradiance, capacity, loss settings, PCS conditions, shading conditions, output control, and degradation rates. Comparing only the results while the underlying assumptions differ will not lead to a correct judgment.

An explanation that is trusted by your supervisor is one that is neither too definitive nor too vague. By distinguishing between statements such as "This item has been verified," "This item is an assumption," "This area has a large impact on power generation," and "This area has a limited impact," the accuracy of reports is improved.

Practical Ways to Summarize for Explaining to Your Supervisor

Before presenting a PVSyst report to your manager, it is highly effective to prepare a one-page summary. What your manager wants to know is not the entire report but the key points needed for decision-making. The summary should include annual energy production, Specific Yield, PR, main losses, assumptions, concerns, and next actions.

Begin by stating the conclusion up front. For example: "Annual power generation is within the expected range," "Lower than other companies' reports, but the main cause is differences in solar irradiation," "PR is reasonable, but shading losses are large," "A review of wiring losses will be necessary after detailed design," etc., thereby indicating the direction of the assessment at the outset.

Next, organize the key figures. List annual energy production, installed capacity, Specific Yield, PR, solar irradiance, and the main loss rates. However, even when using a table, it's important to add comments as well as numbers. For example, if you write "overall efficiency including loss settings" next to PR, "room for layout improvement" next to shading loss, and "recheck after detailed design" next to wiring loss, it will be easier to use as explanatory material.

After that, explain the main loss factors. For managers, rather than covering every loss, focus on those that have a major impact on power generation, such as shading, temperature, PCS, wiring, soiling, and snow. For each loss, it is also good to indicate whether it is controllable. Temperature losses cannot be completely avoided because they depend on the region and installation conditions, but shading losses and wiring losses can sometimes be improved through design.

Additionally, clarify any unresolved conditions. For example, if the post-development terrain, final layout, cable routes, PCS model, snow settings, output control conditions, soiling losses, maintenance plans, etc. are not finalized, they may affect power generation. Tell your supervisor, "The current power generation is based on these conditions, and a reassessment will be necessary once the unresolved items are finalized."

Finally, indicate the next actions. Don’t stop at reviewing the PVSyst report; it’s important to connect it to design reviews, condition verifications, competitor comparisons, preparation of customer-facing materials, organization of documents for financial institutions, on-site checks, and so on. Since supervisors often want to know who should check what next, organizing the actions increases the value of the report.

In practical work, it is efficient to fix the order of explanation. First the conclusion, then the key figures, then the assumptions, then the loss factors, and finally the risks and countermeasures. By using this format, even if the numbers change for each case, you can stabilize the quality of your explanations.

Perspectives for Linking PVSyst Results to On-site Verification

A PVSyst report is the result of a desk study, but solar power plants are greatly affected by actual site conditions. Therefore, when explaining to your supervisor, it is also important to adopt the perspective of linking PVSyst results to on-site verification.

When checking shading in particular, it is necessary to confirm not only the drawings and the PVSyst model but also the on-site topography, surrounding trees, buildings, utility poles, slopes, and shadows cast by nearby mountains. If shading losses are large, confirming on-site not only the values in PVSyst but also which areas will be shaded at which times of day will reveal the feasibility of countermeasures.

Checking the terrain is also important. If ground elevation changes before and after site preparation, the height of the racking and inter-row shading will also change. In projects with complex topography, it can be difficult to understand shading and constructability from 2D drawings alone. By using point clouds and 3D models to confirm the site shape, it becomes easier to verify whether PVSyst's assumptions match reality.

On wiring losses, on-site verification is also important. Even if a fixed loss rate is entered in PVSyst, losses can increase if actual cable routes become longer. Checking the placement of PCS and junction boxes, the routing of cable racks, the routes of underground burial, and the locations of step-up equipment can improve the validity of the wiring loss assessment.

Also, snow and soiling need to be considered in light of the local environment. Actual power generation will vary depending on whether the surroundings are agricultural land, whether there is a lot of dust, whether the site is close to the sea and subject to salt damage, whether the slope causes snow to shed easily after snowfall, and whether there are snow removal or cleaning operations. It is important to confirm that the soiling losses and snow conditions set in PVSyst match the on-site operations.

For on-site checks like this, high-precision GNSS positioning and AR displays using smartphones can be useful. For example, by using a system that enables GNSS positioning and AR display combined with an iPhone, such as LRTK, you can verify drawing locations and equipment positions on site and more easily grasp the discrepancies between desk-based design conditions and the actual site. If you can do more than just explain the PVSyst results and also indicate which conditions should be checked on site, your reports to supervisors will be more practical.

PVSyst is a powerful tool for calculating energy production, but if the site information on which it is based is inaccurate, the reliability of the results will decline. Therefore, when explaining a PVSyst report to your supervisor, it is important to also convey what should be checked on site to make the results more reliable.

Summary

When explaining a PVSyst report to your manager, it's important to organize the information in the order required for business decisions rather than reading the report page by page in detail. First, present the annual energy production as the conclusion; next, normalize for size using the Specific Yield. Then confirm the overall plant efficiency with the PR and check whether the irradiance and meteorological conditions are reasonable.

For practical decision-making, merely knowing whether the energy production is high or low is insufficient. Using a Loss Diagram, you need to identify where generation is being lost and explain the main loss factors such as shading, temperature, wiring, PCS, soiling, and snow. Additionally, by checking that input conditions—installed capacity, modules, PCS, tilt angle, azimuth, shading, wiring losses, etc.—match reality, you can assess the reliability of the PVSyst results.

The final points to convey to your manager are the conclusion, the primary cause, the risks, and the next actions. If you clarify whether the annual energy yield is within the expected range, whether the PR (performance ratio) is reasonable, what the main factors are that are suppressing generation, what the unresolved conditions are, and what should be checked next on site or in the design, the PVSyst report will become not just a simulation document but a document that can be used for decision-making.

Reading a PVSyst report to explain it to your manager is not just about knowing a lot of technical terms. What’s important is organizing complex results into energy production, efficiency, losses, assumptions, risks, and countermeasures and communicating them. Once you master this framework, you will be able to use PVSyst practically in a variety of situations, such as internal reporting, client explanations, comparing other companies’ reports, design reviews, and explanations for financial institutions.