EU-Wide Gridded Solar Power Forecasting
Provide a list of your power plant properties and receive precise power forecasts. Easily generate forecasts for a large number of assets without requiring historical generation data for every specific site.
Up to 5 Days Ahead: Real-time hourly forecasts updated 4x per day.
Archive Forecasts: Historical evaluations of our 5-day forecasts are available from September 2025 (updated once per day at midnight).
Complete EU Coverage: 23.5°W to 62.5°E in longitude, 29.5°N to 70.5°N in latitude with a spatial resolution of 0.0625°.
Under the Hood: The Sunsei Model
We developed a general, end-to-end trained model backed by 5 years of training data and 4,000+ solar panel installations.
Deep Learning Irradiance Model
The model uses weather forecasts from the ICON-EU model (clouds, humidity, temperature, wind, albedo), estimated clear sky irradiances, and solar angles to forecast the DNI and DHI for each location.
Physical Transformation
Our physics model takes the forecasted irradiance alongside your specific power plant parameters (tilt, azimuth, capacity) to transform the irradiance forecast into a power production forecast. We incorporate trainable parameters to accurately estimate panel temperature and how it affects overall system efficiency.
End-to-End Training
The physics model acts as a differentiable layer. Because the model does not use power measurements as input, we can deliver power forecasts for entirely new locations without requiring any historical generation data.
Expanded NWP Model Support
Sunsei currently uses ICON-EU, with support for additional NWP models on the way. Get in touch to stay up to date on expanded model coverage, product updates, and what’s next.
Energy Forecasting Backed by Medius
Sunsei is developed by Medius, a custom software development company founded in 2002 with proven expertise in artificial intelligence, data analytics, and complex enterprise systems integration.
Relevant Energy Projects
LEONARDO Forecasting Platform
Medius participated in the four-company LEONARDO consortium, a €1.8 million project focused on AI and data analytics for forecasting renewable-energy production.
Forecasting in Operation
Medius provides intraday, day-ahead, and extended production forecasts for the 3 MWp Prapretno solar power plant in Slovenia.
Data Access
Real-time forecasting plans scale with the number of power plant locations in your portfolio.
No credit card required until November.
Developer
Evaluate our capabilities using extensive historical data.
- Access to complete historical data archive
- Unlimited power plant locations
- No real-time forecasts
Operational
Real-time forecasting scaled to your portfolio size.
- Real-time forecasts, updated 4x per day
- Priority email support
- Includes Developer functionality
Enterprise
For utility-scale operations requiring custom solutions.
- More than 5,000 locations
- Model tuning on your historical production data
- Priority email support
- Includes Developer functionality
Get API Access
Integrate precise solar forecasting directly into your operations.
During our Early Adopter phase, all API endpoints are fully accessible. Register before the end of October 2026 to start your 3 months of completely free access.
Generate Your Access Key
Provide your details, and we will send you a personal API key.
No credit card required until November.