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FreeGreenius is the freely available version of the software greenius which has been developed at the Institute of Solar Research of the German Aerospace Center (DLR) since several years.

It is made for fast and simple performance calculations of Concentrating Solar Power (CSP) and other renewable energy systems based on hourly plant performance simulations. The initial focus was on renewable electricity generation with emphasis on concentrating solar power generated by parabolic trough plants. Greenius is continuously extended e.g. to simulate also solar towers, solar process heat generation and solar cooling. It offers a combination of fast technical performance calculations, economical calculations and user interfaces for parameter manipulation and analysis of the results. Third party meteorological data and performance maps generated with other software tools may be integrated easily.

In the past the publicly available version was restricted in modeling capabilities and only those users who have bought a full version had access to all options. We had many requests from potential users but due to limited resources we could not distribute it. Now we can offer a full version of Greenius for everybody free of charge.


The development and extension of greenius has been funded by several public bodies. Their funding is gratefully acknowledged and they are mentioned in the following paragraphs.

Publishing, further development and user support for FREE greenius is currently enabled trough funding by the German Federal Ministry for Economic Affairs and Energy based on a decision by the German Bundestag (Funding reference number: 0325427)

The addition of models for solar cooling with concentrating and non-concentrating collectors was funded by the European Commission under the 7th Framework Programme (Contract no. TREN/FP7EN/218952)

The addition of models for process heat generation with concentrating and non-concentrating collectors was funded by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety based on a resolution of the German Parliament (Funding reference number: 0329609A)

The extension of greenius for concentrating PV systems was funded by the European Commission under the 6 Framework Programme (Contract no. SES6-CT-2003-502626)

The development and implementation of greenius started in 1999 and funding was provided by the European Commission under the ALTENER II Programme (Contract no. XVII/4.1030/Z/98-268)

The responsibility for the content is on the authors.