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European Solar Test Installation (ESTI): "a leading position in the international landscape"

Solar cell test evaluation
Feb 05 2016

In its role as photovoltaic reference laboratory, JRC’s ESTI facility based in Italy recently underwent an external assessment by the Italian National Accreditation body (ACCREDIA) composed of a team of international assessors to verify its implementation of the International guide for reference laboratories ( ISO 17025). The assessment panel described ESTI as having "a leading position in the international landscape".

With the annual world PV production exceeding 55 GW in 2015 and a market value reaching over €25bn solely for the module components, this resulted in overall system investment of €80bn in 2015. The methods and standards for the calibration of the power of photovoltaic systems are vital. At present, the market is defined by the price per watt (EUR per watt peak of rated power of the PV modules). As such it relies on the highest level of precision and guarantee of the power measurement for the PV industry (profit), the consumer (guarantees of value for money) and the national utilities (sizing and guarantee of supply and interoperability). To support the European Union's objective of attaining an increasing share of renewable energies in the market (20% in 2020 and at least 27% in 2030), the JRC team works together with policy makers, industry and the research community to monitor the progress of this technology and help develop the solutions for the future.

During the assessment the ACCREDIA team verified the recent ESTI proposal on a new approach to reduce the uncertainty of the rating of photovoltaic solar modules and confirmed it can be introduced under the accreditation scheme. Such a measure would halve the uncertainty on the power labelling of products for the market. This could result in improved profit margin for the industry in the region of €400mil and simultaneously provide a better guarantee for consumers.

In addition to the confirmation of the excellence of ESTI, ACCREDIA also assessed its ability to hold "Flexible scope". This means the facility is deemed competent beyond applying existing international standards, as it has demonstrated the ability to develop and implement new tests and standards in response to a dynamic and rapidly changing technologies and markets. The assessment also included recommendations for further improvement.


Photovoltaic solar panels are bought and sold on the basis of their maximum power output. Manufacturers include a margin on this value to allow for small variations in manufacturing and measurement. The possibility to tighten this margin (typically few percent) brings an economic benefit to both producers and investors.

On the R&D side, reducing uncertainty increases the possibility to clearly identify the impact of new materials and processes. For these measurements both industry and the photovoltaic research community rely on a calibration chain ultimately traceable to the SI (Système International d'Unités) irradiance scale. The results open the way to cheaper and faster calibration of secondary reference devices for industry and research to the same level or even lower uncertainty.

The analysis has been published in "Metrologia" "Reduction of uncertainties for photovoltaic reference cells" the world's leading journal on metrology, published by IOP Publishing on behalf of Bureau International des Poids et Mesures (BIPM).