EU Science Hub

European Solar Test Installation

The European Solar Test Installation (ESTI) is a European reference laboratory for calibration of photovoltaic (PV) devices and for the verification of their energy generation. Since its launch in the late 1970’s, it also has been the forefront of the development of international standards for the assessment of electrical performance of PV products and for their reliability. ESTI is located at the JRC Ispra site in Italy.

Take a virtual tour


ESTI has a unique range of class AAA solar simulators as well as outdoor facilities for accurate calibration, testing and long-term assessment of PV cells and modules.

/jrc/en/video/estiEuropean Solar Test Installation (ESTI)

Ensurance of Measurements Traceability to Primary Measurement Standards

To have legal validity, all measurements (including PV) are required to have an unbroken traceability chain to international primary measurement standards as well as a calculation of their uncertainty. For PV devices the most important and difficult aspect is the irradiance determination, for which ESTI is accredited for three methods.


ESTI maintains a laboratory management system that is compliant to the ISO/IEC 17025 and is accredited for the calibration of photovoltaic devices (LAT 225) by the Italian accreditation body ACCREDIA. The accreditation scheme includes a flexible scope that allows ESTI to develop and implement internally new measurement procedures and methods. The validation procedures applied by ESTI before introducing any variation in the methods under “flexible scope” are described in our instruction Validation of Methods. We maintain a list of methods that indicates which tests and methods have been modified by ESTI under our “Flexible Scope of Accreditation”; the list can be consulted for reference.

ESTI services for the PV community

  • Free-of-charge calibration service of reference devices for national laboratories and verification on request of technologies developed in EU programmes
  • Collaborative research with industrial partners on new materials and/or concepts to promote European competitiveness and improved international standards
  • Funded R&D in shared-cost European programmes
  • Calibration service for external customers, focusing on new technologies and respecting subsidiarity principles
For the calibrations price list or for requesting information on our services, please contact:

ESTI Meteo Tower Data online

Comprehensive metrological solar resource data are essential for evaluating the results of the European Solar Test Installation (ESTI)'s outdoor exposure testing on PV modules. A permanent monitoring of the significant environmental parameters (see details) is carried out thanks to the ESTI meteo tower, whose data are publicly available on the ESTI meteo tower website.

Large-Scale Façade

In 1994, an amorphous silicon array was installed under ESTI supervision on the façade of the ELSA building housing the European Laboratory for Structural Assessment. At the time, it was the largest façade installation in the world using amorphous silicon technology.