Solar Radiation Forecasting and Historical Data

Solar Radiation Forecasting and Historical Data

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How does solar data support the energy industry?

Accurate solar irradiance and weather data with global coverage: Historical, real-time and forecast

Solar Radiation Forecasting and Historical Data Enables Our Industry

Our purpose at Solcast is to enable you to build, operate and manage the solar powered future.  And no source of information is more important for the solar energy industry than solar radiation data.  Our team believes we have the most accurate and most widely available historical, real-time and forecast solar radiation data available, and we are committed to improving it every week.  But don’t take our word for it! We welcome you to test it out and tell us what you think.

Our data is global, live and rapid update

Using a fleet of five weather satellites, we operate a global, rapid update solar radiation database covering all continents and most major island groups (outside of the polar regions).  This database of our “Estimated Actuals” reaches back more than 10 years, through to recent, real-time and forecast data available for retrieval via the Solcast API service.

This API allows for easy manual download or automated fetching of historical, real-time and forecast solar radiation data, and includes commonly required fields such as Global Horizontal Irradiance (GHI), Direct Normal Irradiance (DNI), Diffuse Horizontal Irradiance (DHI) and a selection of other related weather variables, including temperature and cloud (check out our API documentation for more details).


Image Description: An example of Solcast solar radiation estimated actuals data validated against a ground based pyranometer

Our customers use our solar radiation and weather data to:

  • Quickly and cheaply prospect and develop new solar projects
  • Create or improve in-house solar power forecast modelling systems
  • Conduct DIY experiments or build new products/apps
  • Estimated PV system yield with modelling tools such as PVSyst
  • Test and commission utility scale solar farms
  • Conduct research (did you know, we offer free recent solar radiation data to University students and researchers?)

Check it out for yourself.

Access the solar radiation forecasting and estimated via our API!

We suggest you get started by checking our accuracy at a nearby measurement site of relevance to you.  You can accomplish this by signing up for the Solcast API and using the latitude and longitude of that nearby site to grab recent solar radiation data via our Estimated Actuals.

The danger of over optimising for site data

One thing you’ll find is that some data vendors will over optimise their data to reference sites. This means using a known site (such as an NREL site in North America), to nudge/train or "bend" your data to create artificially low bias statistics.  We have found that the benefits of such approaches disappear after travelling only a short distances away from the measurement site. Since high-quality irradiance measurement sites are sparse (and most solar assets are over 500km from the nearest measurement site!) you want a data set that is optimised for everywhere, rather than over-optimised to one site.

However, in cases where local solar radiation sites are available, such as for a utility scale solar farm, we can use your measured solar irradiance data to help improve the solar power forecasting through our ‘tuning’ technologies.

Try out our solar radiation forecasting and estimated actuals product now!

Sign-up for the Solcast API