PVGIS (Photovoltaic Geographical Information System) is a free tool developed by the Joint Research Centre of the European Commission. It uses satellite data to calculate how much energy a solar panel installation will produce at any location worldwide.

How accurate is PVGIS?

PVGIS uses multi-year satellite data (2005-2020) and is generally accurate within 5-10% for annual production estimates. However, it doesn't account for local shading, panel degradation, or unusual weather patterns.

What is the optimal tilt angle for solar panels?

The optimal tilt angle depends on your latitude. In the US, it's typically 25-40 degrees. PVGIS can calculate the optimal angle for maximum annual production at your specific location using the 'Optimize slope' option.

What does kWh/kWp/year mean?

This is the specific production - the amount of energy (kWh) produced per kilowatt-peak of installed capacity per year. It allows comparing location efficiency regardless of installation size. Values range from 800-1800 depending on location.

PVGIS - Free Solar Energy Production Calculator

Photovoltaic Geographical Information System (PVGIS) is a free tool from the European Commission that allows you to precisely estimate energy production from a photovoltaic installation at any location worldwide.

Free

No registration or fees

Precise

Satellite data for your location

Detailed

Monthly and yearly production

Official

Data from EU Joint Research Centre

Open PVGIS How to Use?

What is PVGIS?

PVGIS (Photovoltaic Geographical Information System) is an interactive tool developed by the Joint Research Centre (JRC) - the European Commission's science and knowledge service.

The tool uses multi-year satellite data on solar irradiance, temperature, and other atmospheric factors to precisely calculate how much energy a photovoltaic installation will produce at a specific location.

Key Capabilities:

Energy production calculation - for any PV system in Europe, Africa, parts of Asia, and the Americas
Tilt angle optimization - find the optimal angle for maximum production
Orientation analysis - compare east, west, and south-facing systems
Hourly data - download detailed production data for every hour of the year
Loss accounting - temperature, reflection, cabling losses

Joint Research Centre

The European Commission's science and knowledge service, headquartered in Ispra, Italy. Provides independent scientific advice for EU policy.

PVGIS Data: Solar irradiance comes from the satellite databases SARAH-2 (Europe) and ERA5 (global), covering years 2005-2020.

How to Use PVGIS? Step by Step

Select Your Location

When you open PVGIS, you'll see a world map. You can:

Click on the map at the location where you plan to install panels
Enter an address in the search field (e.g., "Phoenix, Arizona")
Enter GPS coordinates if you know them

Tip: The more precisely you indicate the location, the more accurate the results. Even a few miles difference can affect irradiance (e.g., proximity to mountains, coast).

PVGIS interface - location selection and parameters

PVGIS interface with world map and PV installation parameters panel

Choose Calculation Type

PVGIS offers several types of analysis:

Grid-connected PV

The most popular option - for installations connected to the grid. Calculates annual and monthly energy production.

Off-grid PV

For autonomous installations with energy storage, not connected to the electrical grid.

Set Installation Parameters

Enter data for your planned or existing installation:

System Size (kWp)

Total peak power of panels. E.g., 10 panels at 500Wp = 5 kWp.

Tilt Angle (slope)

Panel angle relative to horizontal. In the US, optimal is typically 25-40 degrees depending on latitude. You can select "Optimize slope" for automatic optimization.

Azimuth (orientation)

Panel direction: 0 degrees = south, -90 degrees = east, 90 degrees = west.

Advanced Loss Settings:

System loss - losses in inverter, cables (default 14%)
Mounting position - free-standing vs roof-integrated (affects cooling)

Analyze Results

After clicking "Visualize results" you'll receive:

Monthly Chart

Bar chart of energy production for each month of the year. You'll clearly see the difference between summer (May-August) and winter.

Results Table

Detailed data: annual production (kWh/year), irradiance (kWh/m2), losses, optimal tilt angle.

PVGIS results - monthly energy production chart

Example PVGIS results: monthly production chart and data table (showing kWh/year for a 1 kWp installation)

Interpreting Results - What Do the Numbers Mean?

Yearly PV Energy Production (kWh/year)

The most important value! How much energy your installation will produce in a year.

Example for Phoenix, AZ:
A 5 kWp installation: ~8,000-9,000 kWh/year
That's enough to power most homes in the Southwest!

Specific Production (kWh/kWp/year)

Production per 1 kWp of installed capacity. Allows comparing location efficiency regardless of installation size.

Typical US Values:
Southwest (Phoenix): ~1,700-1,800 kWh/kWp
South (Houston): ~1,400-1,500 kWh/kWp
Northeast (Boston): ~1,200-1,300 kWh/kWp

Global Irradiation (kWh/m2)

Total solar energy hitting the panel surface. In the US: ranges from 1,400-2,200 kWh/m2/year depending on location.

Total Loss (%)

Combined losses: temperature, reflection, inverter, cables. Typically 20-25% of total solar energy.

Optimal Angle

Optimal tilt angle for maximum annual production. In the US: typically 20-40 degrees (depends on latitude).

Solar Irradiance Across the United States

The United States has excellent solar resources, especially in the Southwest. Annual specific production ranges from about 1,000 to 1,800 kWh/kWp depending on location.

Region	Example States	kWh/kWp/year	Characteristics
Southwest	Arizona, Nevada, New Mexico	1,600-1,800	Best solar resources in the country, desert climate
South	Texas, Florida, California	1,400-1,600	Excellent conditions, some humidity in Florida/Gulf Coast
Midwest	Illinois, Ohio, Missouri	1,200-1,400	Good conditions, continental climate
Northeast	New York, Massachusetts, Pennsylvania	1,100-1,300	Moderate conditions, more cloud cover
Pacific Northwest	Oregon, Washington	1,000-1,200	More overcast, but still viable for solar

Solar Irradiance Across Europe

Europe has diverse solar resources, with Southern Europe offering the best conditions. Annual specific production ranges from about 800 to 1,700 kWh/kWp depending on location.

Region	Example Countries	kWh/kWp/year	Characteristics
Southern Europe	Spain, Portugal, Italy, Greece	1,400-1,700	Best solar resources in Europe, Mediterranean climate
Central-South	Southern France, Croatia, Slovenia	1,200-1,400	Very good conditions, transitional climate
Central Europe	Germany, Austria, Czech Republic, Poland	1,000-1,100	Good conditions, continental climate
Western Europe	France, Belgium, Netherlands, UK	900-1,100	Moderate conditions, maritime influence
Northern Europe	Denmark, Sweden, Norway, Finland	800-1,000	Lower irradiance but long summer days compensate

Practical Tips

Best Practices

Check multiple locations - even a few miles difference can change results
Use "Optimize slope" - PVGIS will find the optimal angle
Download hourly data - useful for more detailed analysis
Compare different orientations - east/west split can be better for self-consumption
Use realistic losses - 14% is minimum, often more in practice

Things to Watch Out For

PVGIS doesn't account for shading - trees, chimneys, neighboring buildings
Historical data - results are based on past weather, future may differ
Panel degradation - PVGIS doesn't account for efficiency loss over time
Local conditions - fog, air pollution can reduce production
Mounting type - roof-mounted panels get hotter than ground-mounted

Ready to Explore Solar Panel Options?

Open PVGIS Browse Solar Panels

Sources and Documentation

PVGIS 5.2 (current version) uses SARAH-2 satellite data for Europe and ERA5 for the rest of the world, covering the period 2005-2020.