PVsyst 8.1 Grid-Connected Simulation : The Complete Engineer’s Walkthrough (2026)

Introduction

If you work in photovoltaics — as a design engineer, EPC contractor, energy consultant, or project finance analyst — PVsyst needs no introduction. Developed by the University of Geneva, it is the undisputed global standard for PV system simulation. Lenders, independent engineers, and certification bodies worldwide accept PVsyst output as the reference document for bankable energy yield assessments.

Version 8.1, released in 2026, builds on the architectural overhaul introduced in version 8 and adds a set of meaningful improvements: sub-hourly simulation capability, refined orientation management, an updated Meteonorm 8.2 climate database, and a new command-line interface (PVsystCLI) for batch automation. If you are migrating from version 7.x or early 8.x builds, some parts of the interface will look different — this guide covers everything you need to know.

We will walk through every step of creating a complete grid-connected simulation from scratch: project creation, geographic site setup, meteorological data import, orientation and system definition, module and inverter selection, loss configuration, shading modeling, simulation execution, results analysis, and final report generation.

💡 Note: Full simulation capability requires a licensed version of PVsyst 8.1. You can get the complete licensed version from Docrack.me — PVsyst 8.1 Download.

---

What’s New in PVsyst 8.1 Compared to Earlier Versions?

Before diving into the walkthrough, it is worth understanding what changed in version 8.1 — especially if you’re coming from version 7 or the early point releases of version 8.

1. Orientation-Centric Project Structure

In PVsyst 7 and earlier, projects were organized around sub-arrays. Starting with version 8, Orientation has become the central organizing concept. Every sub-array, 3D shading object, and tracker configuration is now grouped under an orientation. This makes multi-orientation projects (mixed-tilt rooftops, east-west systems, bifacial ground-mount with trackers) significantly easier to manage.

If you open a version 7 project in PVsyst 8.1, it will be automatically converted to the new structure. Review the imported orientation assignments carefully after conversion.

2. Sub-Hourly Simulation

For the first time in PVsyst history, version 8.1 supports sub-hourly simulation. If you import meteorological data at minute-level resolution (from Meteonorm 9 or compatible sources), PVsyst can run the entire annual simulation at sub-hourly time steps. This is particularly valuable for:

• Systems with grid power export limits (clipping behavior is more accurately captured at sub-hourly resolution)
• Battery storage systems where dispatch logic depends on intra-hour power fluctuations
• High-accuracy financial models where P90 uncertainty needs to be minimized

3. Meteonorm 8.2 Integration

PVsyst 8.1 ships with Meteonorm 8.2, which features improved interpolation algorithms and expanded station coverage compared to the Meteonorm 7.x used in PVsyst 7. For sites in the Middle East, Central Asia, and Africa, the data quality improvement is meaningful.

4. Updated NSRDB Physical Solar Model v4

The NASA NSRDB database accessed within PVsyst has been updated to use the Physical Solar Model v4 (PSM v4), replacing the v3 used in earlier releases. This improves accuracy for North and South American sites in particular.

5. PVsystCLI

A new command-line interface bundled with the PVsyst 8 installer that allows automated simulation runs via scripts. For consultants running dozens of scenarios (sensitivity analysis, P50/P90 assessments, row spacing optimization), this is a significant productivity tool.

6. Faster Electrical Shading Calculations

The I/V curve-based electrical shading calculations — the most computationally intensive part of any simulation involving near shading — now run up to 6x faster in multi-threaded mode compared to version 7. On an 8-core machine, what previously took minutes now takes seconds.

---

Prerequisites: What You Need Before You Start

Gather the following information before opening PVsyst:

Site and System Data:

• GPS coordinates of the site (latitude, longitude)
• Altitude above sea level (meters)
• Installed capacity target (kWp) or available roof/land area
• PV module model (manufacturer’s datasheet — ideally IEC or TÜV certified)
• Inverter model and configuration (single MPPT, multi-MPPT, central, string)
• Mounting tilt angle and azimuth (or structural drawings if rooftop)
• Any known near shading obstacles (buildings, trees, chimneys, other rows of panels)

Minimum System Requirements for PVsyst 8.1:

• Windows 8, 10, or 11 (32-bit or 64-bit)
• RAM: 4 GB minimum, 8 GB recommended for large projects with 3D shading
• Disk space: 2 GB for the application plus space for project files
• Internet connection: required for downloading meteorological data from online sources

---

Step 1 — Installing, Activating, and Launching PVsyst 8.1

After installation and license activation, launch PVsyst 8.1. The main Dashboard presents four primary navigation areas:

• Project — create, open, and manage simulation projects
• Databases — browse and edit the component database (modules, inverters, batteries, transformers)
• Tools — standalone tools including the horizon tool, meteo file editor, and economic assessment
• Help — integrated documentation and version release notes

Take a moment to navigate to Databases → PV modules and verify that the database has been updated. PVsyst periodically publishes database updates that include new manufacturer data — if your target module is recent (2024–2026), make sure you have the latest database version installed.

---

Step 2 — Creating a New Project

From the Dashboard, navigate to Project → New or click New Project on the home screen.

The New Project dialog asks for:

Project Name: Use alphanumeric characters and underscores — avoid spaces and special characters, as the project name becomes part of the file path. Good examples: GroundMount_Arizona_50MW, Rooftop_Munich_500kW, Agrivoltaic_Morocco_10MW.

Comment: A free-text description field. You can write in any language here. Use it to record client name, project reference number, revision history, or anything that helps identify the project later.

Geographical Site: The most important field. Click the … button to open the site selection window.

Setting the Geographic Location

PVsyst 8.1 provides two methods for defining your site:

Method 1 — Interactive Map: A built-in map (Bing or OpenStreetMap) allows you to click your site location directly. Type a city name or address in the search bar to navigate there quickly. For utility-scale projects, zoom in to the exact parcel.

Method 2 — Direct Coordinate Entry: For precise positioning, type the GPS coordinates manually. This is the preferred approach for professional reports.

Reference coordinates for common project locations worldwide:

Region	City	Latitude	Longitude	Altitude (m)
Middle East	Riyadh, SA	24.69	46.72	612
Middle East	Dubai, UAE	25.20	55.27	5
Europe	Madrid, Spain	40.42	-3.70	667
Europe	Munich, Germany	48.14	11.58	519
Africa	Ouarzazate, Morocco	30.92	-6.89	1136
USA	Phoenix, AZ	33.45	-112.07	331
USA	Denver, CO	39.74	-104.98	1609
South Asia	Rajasthan, India	27.02	74.22	243
Australia	Perth	-31.95	115.86	20
South America	Atacama, Chile	-24.50	-69.25	2440

Always enter altitude. Atmospheric pressure decreases with altitude, which affects the Air Mass calculation and therefore the effective irradiance reaching the modules. At 2,000 m elevation, atmospheric pressure is roughly 80% of sea level — an error that compounds through the entire simulation.

Selecting Meteorological Data

After confirming the site location, PVsyst shows available meteorological data sources for your coordinates. The available options depend on the site location and your internet connection:

• Meteonorm 8.2 — Recommended default for most locations globally. Interpolates from 8,000+ weather stations. Works offline once installed.
• NASA NSRDB v4 — Best accuracy for North and South America. Requires internet connection to download.
• PVGIS-TMY 5.2 — Excellent for Europe, Africa, and the Middle East. EU-funded, free, requires internet.
• Solcast TMY — High-resolution satellite-based data, best absolute accuracy globally. Requires a Solcast subscription.
• Solar Anywhere TGY — High accuracy for the US market.

Click Import to load the selected data. PVsyst displays a monthly irradiance chart — review it to make sure the seasonal pattern looks correct for your location. In the Northern Hemisphere, June and July should show the highest GHI values; in the Southern Hemisphere, December and January should peak.

Best practice for bankable reports: Always run your simulation with two independent meteorological sources and compare the resulting E_Grid values. A discrepancy greater than 5% requires investigation and explanation in your report. For most sites, Meteonorm + PVGIS or Meteonorm + Solcast is a reliable combination.

Click OK to save the site and return to the project window.

---

Step 3 — Entering the Grid-Connected Design Environment

From the project window, click Grid-Connected. This opens the simulation environment, which is organized into three primary tabs:

• System — define the physical system (orientation, modules, inverter, wiring, losses)
• Shading — define near shading and far horizon
• Simulation — run the simulation and view results

Understanding Variants

Each PVsyst project can contain multiple Variants — independent design scenarios within the same project. This is extremely useful for comparing options: Variant A might be a fixed-tilt system with one module type, Variant B a single-axis tracker with a different module. Both share the same site data and meteorological input but have independent system definitions.

For this walkthrough, we work with the default variant. When you need to compare scenarios, duplicate the variant and modify only the parameters you want to test.

---

Step 4 — Defining the Orientation

In the System tab, Orientation is the first and most fundamental parameter to define. Click Orientation to open the orientation dialog.

Tilt Angle

The tilt angle is the inclination of the panel surface from horizontal (0° = flat, 90° = vertical).

Rule of thumb for maximum annual yield: Set tilt equal to the site’s latitude (±5°). This maximizes the annual energy harvest by balancing summer and winter irradiance.

However, optimal tilt varies depending on your goal:

• For maximum annual energy, use latitude ≈ tilt.
• For maximum winter output (relevant for high-latitude northern European sites), increase tilt by 10–15° above latitude.
• For maximum summer output (relevant for sites with summer peak tariffs), reduce tilt by 10–15° below latitude.
• For rooftop systems, use the actual roof pitch regardless of optimal angle.

Reference tilt angles by latitude band:

Latitude Band	Region Examples	Recommended Tilt Range
0°–15°	Singapore, Lagos, Nairobi	10°–15°
15°–25°	Mumbai, Riyadh, Miami	18°–25°
25°–35°	Phoenix, Shanghai, Cairo	25°–35°
35°–45°	Madrid, Istanbul, Denver	32°–42°
45°–55°	Paris, Berlin, Vancouver	38°–50°

Azimuth

Azimuth defines the compass direction the panel faces:

• 0° = South-facing (maximum annual yield for Northern Hemisphere sites)
• ±90° = East or West-facing (reduces annual yield by 15–25% but shifts generation to morning or afternoon)
• 180° = North-facing (only used in Southern Hemisphere)

For most utility-scale ground-mount projects in the Northern Hemisphere, use 0° (south). For rooftop projects where roof orientation is fixed, enter the actual roof azimuth.

System Type: Fixed Tilt vs. Single-Axis Tracker

Fixed Tilt (FT): Panels are fixed at a permanent angle. Lower capital cost, no moving parts, minimal maintenance. Standard for rooftop and most distributed generation applications.

Single-Axis Tracker (SAT): Panels rotate east-to-west throughout the day following the sun. Typical yield increase: 15–30% over fixed tilt. Higher capital cost and more complex O&M. Standard for large utility-scale ground-mount projects in flat terrain (deserts, plains, agricultural land).

Dual-Axis Tracker: Tracks in both azimuth and elevation. Maximum possible yield but highest cost and complexity. Used in concentrating photovoltaic (CPV) systems and specialized research installations.

For this tutorial, we use Fixed Tilt. PVsyst’s tracker simulation (especially backtracking algorithms) is covered in a dedicated tutorial in this series.

---

Step 5 — Selecting PV Modules

In the System tab, click PV modules to open the component database browser.

Searching the Database

Filter by:

• Manufacturer — type the brand name to narrow the list
• Pnom range — filter by nominal power (e.g., 500–600W for current large-format panels)
• Technology — select from Mono-Si, Multi-Si, CdTe, CIGS, HJT, TOPCon, etc.

Current high-efficiency module technologies (2026):

Technology	Typical Efficiency	Typical Power Range	Notes
TOPCon (n-type)	22–23%	580–640W	Dominant utility technology in 2025–2026
HJT (Heterojunction)	22–24%	560–620W	Best low-light and temperature performance
Mono PERC	20–22%	530–580W	Mature, widely available, cost-effective
Bifacial TOPCon	22–23% + rear gain	580–640W front	Standard for ground-mount projects
Perovskite-Si Tandem	28–30% (lab)	Commercial early stage	Not yet in PVsyst database mainstream

Creating a Custom Module

If your target module is not in the PVsyst database (new releases, regional manufacturers, or custom panels), click New to create a custom entry. You will need the following from the manufacturer’s datasheet:

Electrical parameters at STC (1000 W/m², 25°C cell temperature, AM 1.5):

• Pnom — Nominal power (W)
• Voc — Open circuit voltage (V)
• Isc — Short circuit current (A)
• Vmpp — Maximum power point voltage (V)
• Impp — Maximum power point current (A)
• µVoc — Temperature coefficient of Voc (%/°C or mV/°C)
• µIsc — Temperature coefficient of Isc (%/°C or mA/°C)
• µPmax — Temperature coefficient of power (%/°C)

Physical parameters:

• Module dimensions (length × width in meters)
• Number of cells and cell configuration
• NOCT (Normal Operating Cell Temperature, typically 43–47°C)

Important: PVsyst uses the one-diode model (also called the five-parameter model) internally. When you enter the datasheet parameters, PVsyst automatically fits the model coefficients. If the fit quality indicator shows poor convergence, check whether your datasheet Vmpp/Impp values are internally consistent (Vmpp × Impp should closely equal Pnom).

Use TÜV-certified or IEC 61215-compliant datasheets whenever possible. Some manufacturers inflate Pmax values on marketing datasheets. Using inflated input data will produce optimistically biased simulation results — a serious issue for bankable reports.

Bifacial Modules

For bifacial modules (now standard for most utility-scale projects), PVsyst 8.1 includes a dedicated bifacial simulation model. After selecting a bifacial module, you can define:

• Bifaciality factor — typically 0.65–0.80 for standard bifacial panels
• Ground albedo — the reflectivity of the ground surface under and behind the array (white gravel: ~0.4, dry grass: ~0.2, concrete: ~0.3)
• Rear irradiance calculation — PVsyst models the irradiance incident on the rear face accounting for row spacing, mounting height, and ground albedo

Bifacial gain for typical ground-mount systems ranges from 3–12% depending on albedo and system geometry.

---

Step 6 — Selecting and Configuring the Inverter

Click Inverter in the System tab to open the inverter database.

String Inverters vs. Central Inverters

String inverters (typically 15–350 kW per unit) are connected to individual strings or groups of strings. Each unit operates independently with its own MPPT. Modern high-power string inverters (250 kW+) are now cost-competitive with central inverters for utility-scale projects and offer better partial shading performance.

Central inverters (500 kW – 5+ MW per unit) connect to a combiner box aggregating many strings. Lower unit cost per kW but require precise string matching and the failure of one unit affects a larger portion of the array.

Multi-MPPT Configuration

Most modern string inverters have 2–12 independent MPPT inputs. In PVsyst 8.1, the Multi-MPPT configuration allows you to assign different string groups (with different orientations or lengths) to different MPPT inputs on the same inverter.

This is essential for:

• East-west rooftop systems where the east and west faces need separate MPPT tracking
• Systems with partial shading on some strings
• Mixed-tilt systems where different roof planes feed the same inverter

Stringing Design: Determining Modules per String

The number of modules per string is a critical safety and performance parameter. PVsyst 8.1 calculates the allowable range automatically, but here is the logic:

Maximum string voltage constraint (safety): At the coldest expected temperature (minimum ambient temperature + thermal model), the open-circuit voltage of the string must not exceed the inverter’s maximum DC input voltage:

N_max = V_inverter_max / Voc(T_min)

Minimum MPPT voltage constraint (performance): At the hottest expected temperature (maximum ambient temperature + module heating), the MPP voltage of the string must remain above the inverter’s minimum MPPT voltage:

N_min = V_MPPT_min / Vmpp(T_max)

PVsyst highlights violations with red warning messages. Never ignore a Voc/Vmax warning — it represents a real risk of inverter damage.

DC/AC Ratio (Inverter Loading Ratio)

The DC/AC ratio (also called the inverter loading ratio or clipping ratio) is the ratio of installed DC capacity to inverter AC nameplate power:

DC/AC ratio = DC_peak (kWp) / AC_inverter (kVA)

Industry norms by market:

Market Context	Typical DC/AC Ratio
Premium rooftop (low irradiance, Europe)	1.0 – 1.15
Commercial rooftop (medium irradiance)	1.1 – 1.25
Utility ground-mount (high irradiance, desert)	1.25 – 1.45
Agrivoltaic / dual-use	1.0 – 1.2

A higher DC/AC ratio increases morning and evening generation (when the array is producing below inverter capacity) but causes clipping losses at solar noon when the array would otherwise produce more than the inverter can accept. The optimal ratio depends on local irradiance patterns, tariff structure, and system economics. PVsyst’s Loss Diagram will show you exactly how much energy is lost to clipping for any given ratio.

AC Wiring and Transformer Losses

In the Wiring losses section, define:

• DC cable resistance — PVsyst default is 1.5% resistive loss. For large utility systems with long DC cable runs, calculate the actual resistance and enter it.
• AC cable losses — losses in the low-voltage AC network between inverter and MV transformer
• MV/HV transformer losses — for utility-scale projects with medium-voltage step-up transformers (typically 0.8–1.5%)

For a residential or commercial rooftop system, the default 1.5% wiring loss is usually adequate. For a 100 MW+ utility project with a large collector system, calculating actual cable losses is worthwhile.

---

Step 7 — Configuring System Losses

The loss model is where PVsyst’s accuracy shines. Each loss type can be quantified independently, giving you a transparent audit trail from irradiance to grid energy. In the System tab, navigate to the Losses section.

Soiling Losses

Soiling (dust, dirt, bird droppings, pollen) reduces transmittance through the module glass. PVsyst models soiling as a fixed percentage reduction in irradiance reaching the cells.

Typical soiling loss values by environment:

Environment	Soiling Loss (monthly average)
Arid desert (no cleaning program)	4 – 8%
Arid desert (bi-weekly cleaning)	1.5 – 3%
Semi-arid / Mediterranean	1 – 3%
Temperate (rain-cleaned)	0.5 – 1.5%
Coastal / humid	1 – 2%
Urban / industrial	2 – 4%

For large utility projects, it is worth modeling seasonal soiling variation using the monthly soiling profile in PVsyst rather than a single annual average. Dust accumulation is typically highest in dry seasons and partially self-cleaning after rain events.

Thermal Losses

PVsyst’s thermal model calculates cell temperature at every time step based on:

• Ambient temperature from the meteorological data
• Irradiance on the module surface
• Wind speed (if available in the meteo data)
• Module mounting configuration (thermal coefficients Uc and Uv)

Recommended thermal coefficients by mounting type:

Mounting Configuration	Uc (W/m²K)	Uv (W/m²K/ms⁻¹)
Free-standing (ground-mount, good airflow)	25	1.2
Close to roof (rooftop, limited airflow)	15	1.0
Integrated (BIPV, no rear ventilation)	10	0

Higher cell temperatures reduce module efficiency. For every 1°C increase above STC (25°C cell temperature), power output decreases by approximately 0.35–0.45% depending on the module technology. This thermal penalty is significant for desert locations where cell temperatures can reach 70–80°C during peak hours.

Module Quality and LID Losses

• Module quality loss — accounts for the statistical spread in module power around the nameplate value. Default: 0.5–1%. If you have flash-test certificates guaranteeing +0/-3% tolerance, use 0.5%.
• LID (Light-Induced Degradation) — mono-crystalline PERC modules typically experience 1–2% LID in the first weeks of operation. TOPCon and HJT modules have near-zero LID. Default in PVsyst: 0%.

Mismatch Losses

Even modules from the same production batch have slight variations in electrical characteristics. When mismatched modules are connected in series (a string), the weakest module limits the entire string’s current.

• Power mismatch — default 0.1%, acceptable for well-sorted strings
• Voltage mismatch — default 0.1%

For string-level monitoring systems that actively detect mismatch, these values can be reduced.

Module Degradation

PVsyst’s aging module allows you to define an annual power degradation rate, typically 0.3–0.5% per year for modern modules. This is used in the economic assessment tool rather than the core simulation, but it feeds into P50/P90 multi-year analyses.

System Unavailability

The fraction of time the system is offline due to planned maintenance, unplanned failures, or grid curtailment. For well-operated utility systems, 0.5–1% is typical. Contractual grid curtailment (if applicable to your site) should be included here as well.

---

Step 8 — Shading Definition

The Shading tab in PVsyst handles two separate shading phenomena that must be defined independently.

Far Horizon

The far horizon defines the elevation angle of distant terrain features — mountains, hills, ridgelines, or urban skylines — that block direct beam irradiance at certain solar positions. Even a 2–3° horizon obstruction in the south can cause meaningful losses for high-latitude sites where the winter sun stays low.

To import far horizon data automatically:

1. Click Horizon in the Shading tab
2. Select Import from Meteonorm or Import from PVGIS — both retrieve terrain elevation data from digital elevation models
3. Review the resulting horizon profile overlaid on the sun path diagram — blocked solar positions are shown clearly
4. For flat terrain (plains, deserts, coastal lowlands), the horizon will be near 0° and losses negligible
5. For mountain or valley sites, quantify the loss — it can reach 5–15% of annual irradiance

For sites where you need higher accuracy than the terrain model provides (e.g., a site in a narrow valley, or near a large building not in the terrain database), you can edit the horizon manually by entering elevation angles for each azimuth.

Near Shadings — 3D Scene Tool

Near shading from adjacent objects (other panel rows, buildings, trees, chimneys) is modeled in PVsyst’s 3D Scene tool.

To enter the 3D tool:

1. Click Near Shadings in the Shading tab
2. Click 3D Scene to open the scene editor

Building the 3D scene:

For a standard ground-mount array, you need to define:

• PV field objects — representing the actual panel rows (height, tilt, length, pitch/row spacing)
• Surrounding objects — buildings, trees, fences if they shade the array

PVsyst provides a library of parametric objects:

• Rectangular tables (for fixed-tilt arrays)
• Tracker tables (for single-axis tracker systems)
• Shed objects (for building-integrated or carport systems)
• Generic boxes, cylinders, and prisms for surrounding obstacles

You can also import 3D geometry from external CAD tools in DAE, PVC, or 3DS format — useful when a detailed site model already exists.

Shading calculation method:

PVsyst offers two approaches for calculating the electrical impact of near shading:

Linear (proportional) shading: Assumes that shading reduces the array output proportionally to the shaded fraction of the module area. Fast to compute, appropriate for preliminary design or when electrical shading detail is not required.

Electrical shading (I/V curve method): Calculates the actual electrical behavior of the shaded array by computing I/V curves for every string configuration, properly modeling bypass diode activation. This method correctly captures the non-linear mismatch losses that occur when partial shading activates bypass diodes.

Always use Electrical shading for bankable reports. The linear method can underestimate shading losses by 30–50% in situations where bypass diode activation causes significant mismatch losses (e.g., thin horizontal shading shadows crossing all strings simultaneously — the worst case scenario for row-to-row shading).

In PVsyst 8.1, the electrical shading calculation runs up to 6x faster than in version 7, making it practical to use for all simulation types.

Row spacing and inter-row shading:

For ground-mount systems, PVsyst calculates the optimal row spacing based on your tilt angle, latitude, and acceptable shading loss. A common target is to limit inter-row shading losses to 1–3% of annual yield. The Shading factor table in PVsyst shows how this loss varies by month and hour.

---

Step 9 — Running the Simulation

With all parameters configured, navigate to the Simulation tab.

Pre-Simulation Checks

PVsyst automatically validates the simulation setup and flags issues with color-coded warnings:

Red warnings (blocking issues — must be resolved before simulating):

• String Voc exceeds inverter Vmax at minimum temperature → reduce modules per string
• No meteorological data assigned
• Missing module or inverter definition

Yellow warnings (non-blocking — review and acknowledge):

• DC/AC ratio above 1.5 → high clipping losses expected, confirm this is intentional
• Mismatch losses set unusually high or low
• Thermal coefficients outside typical range

Review all warnings before proceeding. For a first simulation it is normal to have a few yellow warnings; address them one by one.

Executing the Simulation

Click Run Simulation. PVsyst processes all 8,760 hourly time steps (or sub-hourly steps if sub-hourly meteo data is loaded):

For each time step, PVsyst:

1. Retrieves the global horizontal irradiance (GHI) and diffuse irradiance from the meteo data
2. Applies the horizon shading factor for the current sun position
3. Calculates plane-of-array irradiance (transposition from horizontal to tilted surface)
4. Applies near shading factor from the 3D scene
5. Applies IAM (Incidence Angle Modifier) — accounts for increased reflection at non-perpendicular angles
6. Applies soiling loss
7. Calculates cell temperature using the thermal model
8. Calculates DC power from the I/V curve model at the actual cell temperature and irradiance
9. Applies wiring losses and mismatch
10. Calculates inverter AC output including efficiency curve and clipping
11. Applies AC losses (transformer, cable, unavailability)
12. Records E_Grid for this time step

The simulation completes in seconds to a few minutes depending on project complexity and whether sub-hourly or electrical shading calculations are enabled. Progress is shown in the status bar.

---

Step 10 — Analyzing Results

After simulation, PVsyst presents results in the Simulation tab. Here is how to read and interpret the key outputs.

Key Performance Indicators

E_Grid — Energy Injected to Grid (kWh/year) The most important number in the simulation. This is the net AC energy delivered to the grid after all losses. It is the basis for revenue calculations, carbon offset estimates, and financial modeling.

Specific Production (kWh/kWp/year) Energy yield normalized by installed DC capacity. This is the right metric for comparing different sites or system configurations on an equal basis, independent of system size.

Reference specific production by irradiance zone:

Location Type	GHI (kWh/m²/year)	Typical Specific Production
High-desert (Atacama, UAE, Sahara)	2,200 – 2,600	1,700 – 2,100 kWh/kWp
Mediterranean / Middle East	1,800 – 2,200	1,500 – 1,800 kWh/kWp
Southern Europe / US Southwest	1,600 – 2,000	1,400 – 1,700 kWh/kWp
Central Europe / US Midwest	1,100 – 1,400	950 – 1,250 kWh/kWp
Northern Europe (UK, Nordics)	900 – 1,100	750 – 1,000 kWh/kWp

Performance Ratio (PR) The ratio of actual energy yield to the energy that would be produced if the system operated at STC efficiency throughout the year, normalized for irradiance. PR is weather-independent and allows comparison between systems in different climates.

PR benchmarks for modern (2025–2026) systems:

PR Range	Assessment
> 83%	Excellent — high-quality design, good components
78 – 83%	Good — typical for well-designed systems
73 – 78%	Acceptable — some losses worth investigating
< 73%	Poor — significant issue in design or input data

The Loss Diagram — Your Diagnostic Tool

The Loss Diagram (also called the Sankey diagram in some contexts) is the most valuable analytical output in PVsyst. It shows every loss at every stage as a percentage of the input irradiation energy, tracing the path from sunlight to grid energy:

Irradiation on Collector Plane (100%)
  ↓ Far horizon shading loss          (e.g., –0.3%)
  ↓ Near shading: irradiance loss     (e.g., –1.5%)
  ↓ IAM factor loss                   (e.g., –2.8%)
  ↓ Soiling loss                      (e.g., –2.0%)
Effective Irradiance on Modules
  ↓ PV conversion (module efficiency)
  ↓ Thermal loss (temperature effect) (e.g., –4.2%)
  ↓ Module quality / LID              (e.g., –0.5%)
  ↓ Mismatch loss                     (e.g., –0.3%)
  ↓ DC wiring / ohmic loss            (e.g., –1.5%)
DC Energy at Inverter Input
  ↓ Inverter loss (efficiency)        (e.g., –1.8%)
  ↓ Inverter clipping loss            (e.g., –2.3%)
AC Energy at Inverter Output
  ↓ AC cable / transformer loss       (e.g., –1.2%)
  ↓ System unavailability             (e.g., –0.5%)
E_Grid — Energy to Grid              (≈ 82% PR)

If any single loss appears unexpectedly large, it points directly to a parameter that needs investigation. Common diagnostic scenarios:

• Thermal loss > 6% — site is in a very hot climate with inadequate rear ventilation, or the thermal coefficient (Uc) is set too low
• Clipping loss > 5% — DC/AC ratio is high; evaluate whether the yield gain from additional modules justifies the clipping
• Near shading loss > 4% — row spacing may be too tight, or nearby obstacles are more impactful than expected
• Wiring loss > 3% — cable cross-section may be undersized; recalculate actual resistance

Monthly Production Table

The monthly table shows energy generation for each calendar month. Verify the seasonal pattern is consistent with the expected irradiance pattern for your site. For a south-facing fixed-tilt system in the Northern Hemisphere, June and July should be the peak months; December and January the lowest. Any anomaly in the monthly pattern indicates an input data issue.

Comparing Multiple Variants

If you created multiple variants (e.g., different tilt angles, module types, or row spacings), use the Compare variants function to view side-by-side results for E_Grid, PR, and specific production. This is the most efficient way to make evidence-based design decisions.

---

Step 11 — Generating the Final Report

The PVsyst simulation report is the deliverable that goes to clients, lenders, and permitting authorities.

Configuring the Report

Navigate to Report → Settings to configure which sections appear in the report:

• Executive summary
• System description and parameters
• Meteorological data summary and source
• Monthly irradiance and production table
• Loss diagram
• Detailed component specifications (module, inverter)
• Shading analysis results
• Horizon profile

For a basic client report, include everything except the full component database entries. For a bankable Independent Engineer (IE) review report, include all sections plus documentation of which meteorological source was used, the version of PVsyst, and the simulation date.

Exporting the Report

Click Report → Print/Export → PDF. The resulting PDF report:

• Is self-contained with all simulation parameters documented
• Includes the PVsyst version number and simulation date (important for reproducibility)
• Contains all charts and tables formatted for professional presentation
• Is accepted by lenders, IE firms, and project developers worldwide as a standard deliverable

For bankable energy yield assessments, the PVsyst report is typically accompanied by:

• A P50/P90 uncertainty analysis (accounting for inter-annual meteorological variability)
• A comparison of at least two meteorological data sources
• A sensitivity analysis showing how results change with ±5% irradiance variation
• Degradation analysis projecting 20–25 year energy yield

PVsyst’s economic assessment tool supports the multi-year degradation modeling. The P90 analysis typically requires specialized tools (some consultants use Monte Carlo simulation in Python or R on top of PVsyst outputs) or is performed by Independent Engineer firms.

---

Common Mistakes and How to Avoid Them

Mistake 1 — Skipping the Altitude Field

Many users leave altitude at the default (0 m = sea level). At sites above 1,000 m, atmospheric pressure is noticeably lower, which affects Air Mass and reduces the atmospheric scattering of direct beam irradiance. Always enter the correct altitude for your site.

Mistake 2 — Using Marketing Datasheets

Some manufacturers provide “flash test” datasheet values that slightly exceed standard IEC 61215 test conditions. Using inflated Pmax values will bias your simulation results high. Prefer datasheets that show IEC 61215 or TÜV-certified measurements, and if possible, use PVsyst’s verified manufacturer entries rather than creating custom modules from marketing brochures.

Mistake 3 — Ignoring Clipping at High DC/AC Ratios

At DC/AC ratios above 1.35, clipping losses can exceed 3–5% annually. This is not necessarily a design flaw — if the additional modules cost less than the revenue lost to clipping, the oversized DC array is economically optimal. But the clipping must be explicitly calculated and shown in the Loss Diagram, not overlooked.

Mistake 4 — Using Linear Shading for Bankable Reports

Linear shading systematically underestimates row-to-row shading losses because it does not model bypass diode behavior. For any professional report, use Electrical (I/V curve) shading. In PVsyst 8.1, the performance improvement makes this the obvious choice.

Mistake 5 — Not Cross-Checking Meteorological Sources

Running a simulation with a single meteorological source and submitting it as a bankable report is insufficient. Always compare at least two independent sources. If they agree within 3%, you can proceed with confidence. If they differ by more than 5%, investigate why — it may indicate one source has poor coverage for your site, or the site has unusual microclimatic conditions.

Mistake 6 — Underestimating Soiling in Arid Regions

In desert and semi-arid environments, soiling losses without a cleaning program can reach 10–15% annually. A soiling loss study based on local measurement data (or satellite aerosol optical depth data) is worthwhile for large projects. If no data is available, use a conservatively high value (3–5%) for utility-scale desert sites and document the assumption clearly in your report.

---

Advanced Feature: Batch Simulation Mode

For sensitivity analysis or design optimization, PVsyst 8.1’s Batch mode allows you to run multiple simulations with parametrically varied inputs in a single session. You can sweep:

• Tilt angle (e.g., from 20° to 40° in 2° steps)
• Row spacing / ground coverage ratio
• DC/AC ratio
• Soiling loss values

The results are output as a table, making it easy to plot yield vs. tilt or yield vs. GCR curves and identify the optimal design point. For systems with complex financial optimization (LCOE minimization), batch mode feeding into an external economic model is a powerful workflow.

---

Frequently Asked Questions

Is PVsyst 8.1 compatible with Windows 11? Yes. PVsyst 8.1 officially supports Windows 8, 10, and 11 in both 32-bit and 64-bit configurations. No compatibility mode or special settings are required.

How many sub-arrays and orientations can I define per project? PVsyst 8.1 supports an unlimited number of orientations and sub-arrays per project — one of the most significant architectural improvements from version 7, which had a more limited structure.

My Performance Ratio is below 75% — what should I check first? Open the Loss Diagram and identify the largest loss contributor. Common culprits: high thermal losses (hot climate + poor ventilation), significant near shading, high clipping (oversized DC), or elevated soiling. Each of these has a clear remediation path.

Can I export PVsyst hourly results to Excel or Python? Yes. Use Report → Export → CSV to export hourly or monthly simulation data. The hourly CSV includes irradiance, cell temperature, DC power, AC power, and all loss values for every hour of the simulated year — valuable for feeding into financial models or custom analysis scripts.

What is the difference between Pre-sizing and Simulation? Pre-sizing is a fast preliminary sizing tool that estimates system dimensions without running a full hourly simulation. Simulation is the full hourly calculation used for all professional and bankable reports. Always use Simulation for any deliverable.

How do I model a battery storage system in PVsyst 8.1? For grid-connected systems with battery storage, use the Grid-Connected with Storage system type. PVsyst 8.1 allows you to define the battery bank, inverter/charger, and dispatch strategy. A dedicated tutorial on battery storage simulation is included in this series.

How do I validate my PVsyst simulation against real measured data? Use Report → Simulation vs. Monitoring to compare simulated vs. actual production data. PVsyst accepts monitored production data in CSV format. Typical agreement for a well-calibrated simulation against a well-measured system is ±3–5% annually.

---

Conclusion

Creating a complete, bankable grid-connected PV system simulation in PVsyst 8.1 involves eleven distinct steps — from geographic site setup and meteorological data import through system definition, loss modeling, shading analysis, simulation execution, and professional report generation.

The key takeaways from this walkthrough:

• Orientation management is now the central organizing principle of PVsyst 8.1 projects — invest time in setting it up correctly for multi-orientation systems.
• The Loss Diagram is your most important analytical output. Read it carefully every time — it tells you exactly where energy is being lost and guides design optimization.
• Always use Electrical shading (I/V curve method) for near shading in professional reports. In PVsyst 8.1, the performance improvement over version 7 makes this practical for all project types.
• Cross-check meteorological sources. At minimum two independent sources for any bankable report.
• Enter altitude. It is a small step that many people skip but affects simulation accuracy at elevated sites.

Mastery of PVsyst is one of the highest-leverage skills in the solar engineering profession. A well-executed simulation supports better design decisions, stronger investor confidence, and more accurate financial projections throughout the project lifecycle.

💡 Ready to run your first simulation? Download the full licensed version of PVsyst 8.1 from Docrack.me and follow this guide step by step.

---